| 1. |
- Bollmann, Andreas, et al.
(författare)
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Analysis of surface electrocardiograms in atrial fibrillation: techniques, research, and clinical applications
- 2006
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092. ; 8:11, s. 911-926
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Forskningsöversikt (refereegranskat)abstract
- Atrial. fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Neither the natural history of AF nor its response to therapy is sufficiently predictable by clinical and echocardiographic parameters. The purpose of this article is to describe technical aspects of novel electrocardiogram (ECG) analysis techniques and to present research and clinical applications of these methods for characterization of both the fibrillatory process and the ventricular response during AF Atrial fibrillatory frequency (or rate) can reliably be assessed from the surface ECG using digital signal processing (extraction of atrial, signals and spectral analysis). This measurement shows large inter-individual variability and correlates well with intra-atriat cycle length, a parameter which appears to have primary importance in AF maintenance and response to therapy. AF with a tow fibrillatory rate is more likely to terminate spontaneously and responds better to antiarrhythmic drugs or cardioversion, whereas high-rate AF is more often persistent and refractory to therapy. Ventricular responses during AF can be characterized by a variety of methods, which include analysis of heart rate variability, RR-interval histograms, Lorenz plots, and non-linear dynamics. These methods have all shown a certain degree of usefulness, either in scientific explorations of atrioventricular (AV) nodal function or in selected clinical questions such as predicting response to drugs, cardioversion, or AV nodal modification. The role of the autonomic nervous system for AF sustenance and termination, as well as for ventricular rate responses, can be explored by different ECG analysis methods. In conclusion, non-invasive characterization of atrial fibrillatory activity and ventricular response can be performed from the surface ECG in AF patients. Different signal processing techniques have been suggested for identification of underlying AF pathomechanisms and prediction of therapy efficacy.
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| 2. |
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| 3. |
- Bollmann, Andreas, et al.
(författare)
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Atrial fibrillatory rate and risk of left atrial thrombus in atrial fibrillation.
- 2007
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092. ; 9:8, s. 6-621
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Tidskriftsartikel (refereegranskat)abstract
- ims In atrial fibrillation (AF), a relation between electrocardiogram (ECG) fibrillatory wave amplitude and thrombus formation has been sought for long with conflicting results. In contrast, the possible relation between atrial fibrillatory rate obtained from the surface ECG and left atrial thrombus formation in patients with AF is unknown and was consequently evaluated in this study. Methods and results One-hundred and twenty-five patients (mean age 64 ± 12 years, 72% male) with persistent non-valvular AF (mean duration 28 ± 80 days) undergoing transesophageal echocardiography were studied. In all patients, standard 12-lead ECG recordings were acquired before the examination. Atrial fibrillatory rate was determined using spatiotemporal QRST cancellation and time–frequency analysis of lead V1. Atrial fibrillatory rate measured 401 ± 63 fibrillations per minute (fpm, range 235–566 fpm) and was related with age (R = −0.326, P < 0.001), ventricular rate (R = −0.202, P = 0.024), gender (407 ± 62 in males vs. 387 ± 64 fpm in females, P = 0.038) but not AF duration (R = 0.088, P = 0.374), presence of lone AF (408 ± 66 vs. 394 ± 58 fpm, P = 0.228), or beta-blocker or calcium channel blocker treatment (398 ± 63 vs. 405 ± 62 fpm, P = 0.556). Age was the only independent predictor of fibrillatory rate (B = −1.714, P < 0.001). In patients with left atrial thrombus (n = 10), spontaneous echo contrast (SEC) was more frequently present (70 vs. 29 %, p = 0.007) and left atrial appendage (LAA) outflow velocity was lower (26 ± 20 vs. 37 ± 15 cm/s, P = 0.012) than in patients without thrombus (n = 115). In contrast, mean fibrillatory rate, which showed a weak inverse correlation with LAA velocity (R = −0.118, P = 0.048) was not different between both groups (380 ± 56 vs. 403 ± 63 fpm, P = 0.226). Similarly, presence of thrombus and SEC combined was not related with fibrillatory rate. Conclusion Atrial fibrillatory rate obtained from surface ECG lead V1 is not a risk marker for left atrial thrombus formation in AF.
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| 4. |
- Bollmann, Andreas, et al.
(författare)
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Atrial fibrillatory rate and risk of stroke in atrial fibrillation.
- 2009
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092 .- 1099-5129. ; 11, s. 582-586
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Tidskriftsartikel (refereegranskat)abstract
- Aims In atrial fibrillation (AF), a relation between electrocardiogram (ECG) parameters such as fibrillatory wave amplitude and stroke has been sought with conflicting results. In this study, we tested the hypothesis that the atrial fibrillatory rate of surface ECG lead V1 is related to stroke risk and may consequently be helpful for identifying high-risk patients. Methods and results Atrial fibrillatory rate of 79 consecutive patients with AF and embolic stroke (age 83 +/- 7 years, 41% male) was compared with those of a matched AF population without stroke (n = 79). Atrial fibrillatory rate was determined from the surface ECG using spatiotemporal QRST cancellation and time-frequency analysis of lead V1. There was no significant difference in any clinical or echocardiographic variable in patients with stroke compared with AF controls without stroke. Atrial fibrillatory rate measured 373 +/- 55 fibrillations per minute (fpm; range 235-505 fpm) in the entire population. There was no fibrillatory rate difference between stroke patients (369 +/- 54 fpm, range 256-505 fpm) and AF controls without stroke (378 +/- 56 fpm, range 235-488 fpm). There was an inverse correlation between fibrillatory rate and age (R = -0.219, P = 0.006). Individuals aged >/=85 years had a significantly lower fibrillatory rate (356 +/- 44 fpm) than individuals aged 65-74 years (384 +/- 56 fpm, P = 0.033) and individuals aged 75-84 years (384 +/- 60 fpm, P = 0.016). In those subgroups, fibrillatory rates were, however, also similar in stroke patients and AF controls. Conclusion Atrial fibrillatory rate obtained from surface ECG lead V1 is not a risk marker for stroke in AF.
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| 5. |
- Bollmann, Andreas, et al.
(författare)
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Echocardiographic and electrocardiographic predictors for atrial fibrillation recurrence following cardioversion
- 2003
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 14:s10, s. 162-165
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Identification of suitable candidates for cardioversion currently is not based on individual electrical and mechanical atrial remodeling. Therefore, this study analyzed the meaning of atrial fibrillatory rate obtained from the surface ECG (as a measure of electrical remodeling) and left atrial size (as measure of mechanical remodeling) for prediction of early atrial fibrillation (AF) recurrence following cardioversion. Methods and Results: Forty-four consecutive patients (26 men and 18 women, mean age 62 ± 11 years, no antiarrhythmic medication at baseline) with persistent AF were studied. Fibrillatory rate was obtained from high-gain, high-resolution surface ECG using digital signal processing (filtering, QRST subtraction, Fourier analysis) before electrical cardioversion. Univariate and multivariate regression analysis revealed larger systolic left atrial area (Beta = 0.176, P = 0.031) obtained by precardioversion echocardiogram from the apical four-chamber view and higher atrial fibrillatory rate (Beta = 0.029, P = 0.021) to be independent predictors for AF recurrence (n = 13). Stratification based on the regression equation (electromechanical index [EMI]= 0.176 systolic left atrial area + 0.029 fibrillatory rate − 17.674) allowed identification of groups at low, intermediate, or high risk. No patient with an EMI < −1.85 had early AF recurrence, as opposed to 78% with an EMI > −0.25. Intermediate results (40% recurrence rate) were obtained when the calculated EMI ranged between −1.85 and −0.25 (P < 0.001). Conclusion: Fibrillatory rate obtained from the surface ECG and systolic left atrial area obtained by echocardiography may predict early AF recurrence in patients with persistent AF. These parameters might be useful in identifying candidates with a high likelihood of remaining in sinus rhythm after cardioversion.
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| 6. |
- Bollmann, Andreas
(författare)
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Electrical remodeling in arial fibrillation - assessment using surface electrocardiograms, prognostic implications and potential reversal
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The fibrillatory rate of the surface ECG during atrial fibrillation (AF) has been suggested for quantification of the individual atrial remodeling, to monitor interventions and to predict the response to different therapies. In this dissertation, the relation between fibrillatory rate of the surface ECG and (1) clinical and echocardiographic variables, (2) the outcome of cardioversion, (3) circulating markers of inflammation and hemostasis, (4) the risk of left atrial thrombus formation, (5) the risk of stroke, and (6) the effects of candesartan on the fibrillatory rate were investigated in human persistent atrial fibrillation (AF). Fibrillatory rate (in fibrillations per minute, fpm) was determined from the surface ECG using spatiotemporal QRST cancellation and time-frequency analysis. In 124 patients, multivariate linear regression analysis revealed age, gender, left atrial diameter and use of verapamil to be independently related with fibrillatory rate. Fibrillatory rate was reduced by candesartan, but not by placebo with dominant effects in patients with a high fibrillatory rate at baseline. In 123 patients treated with candesartan or placebo but not with class I or III antiarrhythmic drugs, cardioversion success was 100% in patients with a fibrillatory rate < 360 fpm as opposed to 83% in patients with higher rates. In successfully cardioverted patients, risk for AF recurrence was similar in patients with low (64%), intermediate (75%) or fibrillatory rates (63%). In contrast, in 44 patients treated with class I or III antiarrhythmic drugs, uni- and multivariate regression analysis revealed larger systolic left atrial area obtained by precardioversion echocardiogram from the apical 4-chamber view and higher fibrillatory rate to be independent predictors for AF recurrence after two weeks. Negative correlations were found between fibrillatory rate and C-reactive protein, von Willebrand factor, soluble tissue factor and plasminogen activator inhibitor-1 activity. However, these relations were lost after adjustment for age, gender, body mass index and left atrial diameter, except for a weak inverse relation between fibrillatory rate and soluble tissue factor. Fibrillatory rates were similar in patients with or without left atrial thrombus, and also in patients with or without stroke. In conclusion, (1) aging is associated with a fibrillatory rate decrease that may be a sign for advanced atrial remodeling. (2) Candesartan decreases fibrillatory rate, but this effect is restricted to patients with high baseline fibrillatory rates and offers no obvious clinical benefit. (3) Fibrillatory rates lower than 360 fpm are associated with successful cardioversion using monophasic shocks but not with AF recurrence in patients without specific antiarrhythmic treatment. (4) In contrast, in patients treated with class I or III antiarrhythmic drugs, fibrillatory rate and systolic left atrial area obtained by echocardiography may predict early AF recurrence in patients with persistent AF. (5) Fibrillatory rate does not correlate with inflammatory and hemostatic markers after adjustment for age, gender, body mass index and left atrial diameter, and (6) is not a risk marker for left atrial thrombus formation or (7) stroke.
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| 7. |
- Bollmann, Andreas, et al.
(författare)
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Fibrillatory rate response to candesartan in persistent atrial fibrillation.
- 2008
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092 .- 1099-5129. ; 10, s. 1138-1144
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Angiotensin-receptor blockers may exert favourable anti-arrhythmic effects in atrial fibrillation (AF), but their mechanisms are not fully understood. In this study, we tested the hypotheses that (i) candesartan reduces atrial fibrillatory rate and (ii) fibrillatory rate and its response to candesartan are related with the outcome of cardioversion. For this purpose, a post hoc subanalysis of the randomized, placebo-controlled CAPRAF (Candesartan in the Prevention of Relapsing Atrial Fibrillation) trial was performed. Methods and results Patients with AF undergoing electrical cardioversion were randomized to receive candesartan 8 mg once daily (n = 58) or matching placebo (n = 66) and no additional class I or III anti-arrhythmic drugs. Fibrillatory rate was determined from ECG lead V1 at baseline and at the day of cardioversion using spatiotemporal QRST cancellation and time-frequency analysis. The median time on treatment was 29 days. Candesartan reduced fibrillatory rate [399 +/- 48 vs. 388 +/- 49 fibrillations/min (fpm), P = 0.04], but not placebo (402 +/- 58 vs. 402 +/- 61 fpm, P = 0.986). Candesartan effects were only observed if the baseline fibrillatory rate was high [>420 fpm: 445 +/- 21 vs. 415 +/- 49 fpm, P = 0.006 vs. intermediate (360-420 fpm): 397 +/- 19 vs. 391 +/- 37 fpm, P = 0.351 vs. low (<360 fpm): 326 +/- 26 vs. 338 +/- 29 fpm, P = 0.179]. Cardioversion success was 100% in patients with an on-treatment rate <360 fpm vs. 83% in patients with higher rates (P = 0.02). Risk for AF recurrence was similar in patients with low (64%), intermediate (75%), or high on-treatment rates (63%, P = 0.446) and was also independent of candesartan effects on the fibrillatory rate. Conclusion In patients with persistent AF, candesartan decreases the fibrillatory rate, but this effect is restricted to patients with high baseline fibrillatory rates and is not associated with improved cardioversion outcome. Fibrillatory rates <360 fpm are associated with successful cardioversion, but not with AF recurrence.
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| 8. |
- Castells, Francisco, et al.
(författare)
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Principal component analysis in ECG signal processing
- 2007
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Ingår i: Eurasip Journal on Applied Signal Processing. - : Springer Science and Business Media LLC. - 1110-8657. ; , s. 74580-74580
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews the current status of principal component analysis in the area of ECG signal processing. The fundamentals of PCA are briefly described and the relationship between PCA and Karhunen-Loeve transform is explained. Aspects on PCA related to data with temporal and spatial correlations are considered as adaptive estimation of principal components is. Several ECG applications are reviewed where PCA techniques have been successfully employed, including data compression, ST-T segment analysis for the detection of myocardial ischemia and abnormalities in ventricular repolarization, extraction of atrial fibrillatory waves for detailed characterization of atrial fibrillation, and analysis of body surface potential maps.
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| 9. |
- Corino, V. D. A., et al.
(författare)
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A Gaussian mixture model for time-frequency analysis during atrial fibrillation electrocardiograms
- 2007
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Ingår i: 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 2007.. - 1557-170X. - 9781424407880 ; , s. 271-274
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Konferensbidrag (refereegranskat)abstract
- During atrial fibrillation (AF), time-frequency analysis of atrial signal has been applied to describe fibrillatory frequency trends. Recently, temporal changes in spectral shape have been investigated using the spectral profile technique. This profile is computed recursively by fitting each short-time log-spectrum to a spectral template, using amplitude scaling and frequency shifting. The purpose of the present study was to develop a Gaussian mixture model of the spectral profile in order to characterize the shape of AF waveforms. A novel index is introduced, the so-called harmonic index (HI), which reflects properties of the fundamental frequency peak and related harmonics peaks as estimated from the model. The index was tested on recordings from 9 patients with persistent AF, obtained before and after exercise testing. The HI succeeded in monitoring the response to exercise, i.e. change in the spectral profile to a less harmonic pattern, which is consistent with a reduction in AF organization (HI: 0.61±0.11 vs. 0.50±0.19, rest vs. exercise; p≪0.05).
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| 10. |
- Hindricks, Gerhard, et al.
(författare)
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Ability to remotely monitor atrial high-rate episodes using a single-chamber implantable cardioverter-defibrillator with a floating atrial sensing dipole
- 2023
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Ingår i: Europace. - : Oxford University Press. - 1099-5129 .- 1532-2092. ; 25:5
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To allow timely initiation of anticoagulation therapy for the prevention of stroke, the European guidelines on atrial fibrillation (AF) recommend remote monitoring (RM) of device-detected atrial high-rate episodes (AHREs) and progression of arrhythmia duration along pre-specified strata (6 min...<1h, 1 h...<24 h, >= 24h). We used the MATRIX registry data to assess the capability of a single-lead implantable cardioverter-defibrillator (ICD) with atrial sensing dipole (DX ICD system) to follow this recommendation in patients with standard indication for single-chamber ICD.Methods and results: In 1841 DX ICD patients with daily automatic RM transmissions, electrograms of first device-detected AHREs per patient in each duration stratum were adjudicated, and the corresponding positive predictive values (PPVs) for the detections to be true atrial arrhythmia were calculated. Moreover, the incidence and progression of new-onset AF was assessed in 1451 patients with no AF history. A total of 610 AHREs >= 6min were adjudicated. The PPV was 95.1% (271 of 285) for episodes 6min...<1h, 99.6% (253/254) for episodes 1 h...<24h, 100% (71/71) for episodes >= 24h, or 97.5% for all episodes (595/610). The incidence of new-onset AF was 8.2% (119/1451), and in 31.1% of them (37/119), new-onset AF progressed to a higher duration stratum. Nearly 80% of new-onset AF patients had high CHA(2)DS(2)-VASc stroke risk, and 70% were not on anticoagulation therapy. Age was the only significant predictor of new-onset AF.Conclusion: A 99.7% detection accuracy for AHRE >= 1h in patients with DX ICD systems in combination with daily RM allows a reliable guideline-recommended screening for subclinical AF and monitoring of AF-duration progression.
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| 11. |
- Huo, Yan, et al.
(författare)
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Effects of baseline P-wave duration and choice of atrial septal pacing site on shortening atrial activation time during pacing.
- 2012
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092 .- 1099-5129. ; 14:9, s. 1294-1301
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Atrial septal pacing (ASP) has been shown to shorten P-wave duration (PWD) and reduce recurrence of atrial fibrillation (AF) in patients with bradyarrhythmias. However, variability of interatrial connections and atrial conduction properties may explain ASP's modest clinical benefit. The aim of this study was to assess the effect of ASP site on the duration of the paced P wave. METHODS AND RESULTS: Atrial septal pacing at high atrial septum (HAS), posterior septum behind the fossa ovalis (PSFO), and coronary sinus ostium (CSo) was performed in 69 patients admitted for electrophysiological study (52 ± 16 years, 41 men). Twelve-lead electrocardiogram was recorded at baseline and during pacing, signal-averaged for analysis of PWD and P-wave shortening achieved by ASP (ΔPWD = paced PWD-baseline PWD). Baseline PWD was 128 ± 15 ms. The shortest PWD during pacing was achieved at CSo (112 ± 15 ms) followed by HAS (122 ± 14 ms, P< 0.001 vs. CSo) and PSFO (124 ± 21 ms, P< 0.001 vs. CSo). P wave was shortened during pacing in patients with baseline PWD of > 120 ms (n= 50), whereas those with PWD of ≤ 120 ms showed PWD lengthening (n= 19) when paced at HAS (8 ± 17 vs. -12 ± 15 ms, P< 0.001), PSFO (15 ± 17 vs. -12 ± 26 ms, P< 0.001) and CSo (6 ± 16 vs. -25 ± 18 ms, P< 0.001). CONCLUSION: Pacing at CSo is associated with the shortest PWD. P-wave shortening is greatest in patients with baseline PWD of > 120 ms regardless of the pacing site. The results may have implications on the selection of candidates for ASP and the placement of the atrial septal lead, and warrant further evaluation in cases of permanent pacing in patients with paroxysmal AF.
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| 12. |
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| 13. |
- Husser, Daniela, et al.
(författare)
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A Genotype-Dependent Intermediate ECG Phenotype in Patients With Persistent Lone Atrial Fibrillation Genotype ECG-Phenotype Correlation in Atrial Fibrillation
- 2009
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Ingår i: Circulation: Arrhythmia and Electrophysiology. - 1941-3149 .- 1941-3084. ; 2:1, s. 24-28
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Konferensbidrag (refereegranskat)abstract
- Background-Atrial fibrillation (AF) is heterogeneous at the clinical and molecular levels. Association studies have reported that common single-nucleotide polymorphisms in KCNE1 and SCN5A may predispose to AF In this study, we tested the hypothesis that specific AF-associated genotypes confer variation on the appearance of AF assessed by analysis of fibrillatory rate of the atria. Methods and Results-Twenty-six nonrelated patients (21 males, mean age 55 +/- 12 years) with persistent lone AF (median AF duration 5 weeks) not taking class I or III antiarrhythmic drugs were studied. Fibrillatory rate was obtained by spatiotemporal QRST cancellation and time-frequency analysis of the index surface ECG. Genotypes at the AF-associated loci in KCNE1 (S38G) and SCN5A (H558R) were determined by direct DNA sequencing. The atrial fibrillatory rate was 418 +/- 50 fibrillations per minute (range, 336 to 521) in the study cohort. Carriers of the 38 GG KCNE1 genotype (n=13) had significantly lower fibrillatory rates (392 +/- 36 versus 443 +/- 49 fibrillations per minute, P=0.006) compared to those with GS or SS genotype (n=13). Six patients (23%) with fibrillatory rates >450 fibrillations per minute, all had either the GS or SS genotype (chi(2) P=0.008). In contrast, both the heterozygeous and homozygeous SCN5A H558R polymorphism had no effect on fibrillatory rate. There were no significant associations between fibrillatory rate and clinical (age, gender, AF duration, drug treatment) or echocardiographic (left atrial diameter, left ventricular ejection fraction) variables. In multivariable regression analysis, the KCNE1 S38G genotype (SS/GS coded 0, GG coded 1) was the only independent predictor of fibrillatory rate (beta = -0.437, P=0.006) with a SE of the estimate of 44 fibrillations per minute. Conclusions-This study suggests that atrial fibrillatory rate obtained from the surface ECG is at least in part determined by KCNE1 (S38G) genotype, implying that this variant exerts functional effects on atrial electrophysiology. This intermediate ECG phenotype may be useful for elaborating genetic influences on AF mechanisms and identifying subsets of patients for variability in AF susceptibility or response to therapies. (Circ Arrhythmia Electrophysiol. 2009;2:24-28.)
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| 14. |
- Husser, D, et al.
(författare)
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Analysis of the surface electrocardiogram for monitoring and predicting antiarrhythmic drug effects in atrial fibrillation
- 2004
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Ingår i: Cardiovascular Drugs and Therapy. - : Springer Science and Business Media LLC. - 0920-3206 .- 1573-7241. ; 18:5, s. 377-386
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Forskningsöversikt (refereegranskat)abstract
- Specific antiarrhythmic therapy with class I and III drugs for atrial fibrillation (AF) conversion and prevention of its recurrence is frequently utilized in clinical practice. Besides being only moderate effective, the utilization of antiarrhythmic drugs may be associated with serious side effects. In the clinical setting it is difficult to directly evaluate the effects of antiarrhythmic drugs on the individual patient's atrial electrophysiology, thereby predicting their efficacy in restoring and maintaining sinus rhythm. Analysis of the surface electrocardiogram in terms of P-wave signal averaged ECG during sinus rhythm and spectral characterization of fibrillatory waves during AF for evaluation of atrial antiarrhythmic drug effects is a new field of investigation. Both techniques provide reproducible parameters for characterizing atrial electrical abnormalities and seem to contain prognostic information regarding antiarrhythmic drug efficacy. Further research is needed which elucidates the most challenging clinical questions in AF management whom to place on antiarrhythmic drug treatment and what antiarrhythmic drug to prescribe. Analysis of the surface ECG might have the potential to answer these questions.
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| 15. |
- Husser, Daniela, et al.
(författare)
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Electroatriography - Time-frequency analysis of atrial, fibrillation from modified 12-lead ECG configurations for improved diagnosis and therapy
- 2007
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Ingår i: Medical Hypotheses. - : Elsevier BV. - 1532-2777 .- 0306-9877. ; 68:3, s. 568-573
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Tidskriftsartikel (refereegranskat)abstract
- Current atrial fibrillation (AF) management guidelines suggest that initially a decision must be made to apply either a rate control or rhythm control strategy in the individual patient. However, patients' selection remains substantially empirical and the strategy initially chosen often proves unsuccessful and alternative therapies must be adopted. Thus, it seems desirable to develop and apply tests that quantify AF disease state and guide AF management. The overall hypothesis of this paper is that time-frequency analysis of AF from modified 12-lead ECG configurations will improve AF management beyond current diagnostic and therapeutic standards. In particular, we present a novel concept in which 12-lead ECG configurations are modified for time-frequency analysis of AF (electroatriography). While five electrodes (VR, VL, VF, V1, V2) are placed in the conventional position, the other four electrodes (V3, V4, V5, V6) are empirically repositioned anterior or posterior over the atria. By applying spatiotemporal QRST cancellation and time-frequency analysis to these recordings in 19 patients with persistent AF, fibrillatory rate dispersion among individual anterior (25 14 fibrillations per minute, fpm) and posterior leads (16 +/- 11 fpm) as well as individual anterior/posterior rate gradients ranging between -24 and +116 fpm could be identified. Consequently, the portrayed techniques may form the conceptual basis for individualized noninvasive characterization of AF. Initiation of further studies using the described techniques in different AF subsets, for comparisons with intracardiac recordings and outcome of different therapies, e.g. cardioversion, antiarrhythmic drug and ablation therapy may be stimulated. (c) 2006 Published by Elsevier Ltd.
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| 16. |
- Husser, Daniela, et al.
(författare)
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Electrocardiographic characteristics of fibrillatory waves in new-onset atrial fibrillation
- 2007
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092. ; 9:8, s. 638-642
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Tidskriftsartikel (refereegranskat)abstract
- Aims In atrial. fibrillation (AF), fibrillatory waves of surface electrocardiograms (ECG) vary among patients with respect to waveform and repetition rate. The purpose of this study was to (i) explore clinical determinants of new-onset AF and (ii) determine prognostic significance to predict initial treatment outcome of electrocardiographic fibrillatory wave characteristics in new-onset AF Methods and results Twenty-five patients (15 mate, mean age 69 +/- 16 years) with new-onset AF (median AF duration 8 days) were studied. Fibrillatory rate and exponential decay defined as decay of the curve that connects power maxima of dominant and harmonic frequency components were obtained by spatiotemporal. QRST cancellation and time-frequency analysis of the index ECG (before treatment initiation). Baseline AF rate was 380 +/- 50 fibrillations per minute (fpm) (range 222-494); patients' age (beta = - 1.747, P = 0.003) and AF duration (beta = 0.726, P = 0.036) were independently related with fibrillatory rate. AF terminated within 24 h in seven patients, while it was persistent in the other 18 patients. Terminating AF had lower atrial. rate (333 +/- 66 vs. 398 +/- 40 fpm, P = 0.005) and exponential decay (1.03 +/- 0.36 vs. 1.40 +/- 0.37, P = 0.041) than persisting AF Multivariate analysis revealed fibrillatory rate to be the only independent predictor of AF termination or persistence (p = 0.031, P = 0.031). Sensitivity and specificity for predicting AF termination were strongly related to fibrillatory rate (area under the curve = 0.817). Sensitivity and specificity were 89% and 71% for a fibrillatory rate of 355 fpm. Conclusions Fibrillatory rates vary substantially among patients to new-onset AF and are related to patients' age and AF duration. Lower fibrillatory rates indicate higher chances of spontaneous AF termination within 24 h.
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| 17. |
- Husser, Daniela, et al.
(författare)
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Frequency analysis of atrial fibrillation from surface electrocardiograms
- 2004
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Ingår i: Indian Pacing and Electrophysiology Journal. - 0972-6292. ; 4:3, s. 122-136
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Tidskriftsartikel (refereegranskat)abstract
- Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Neither the natural history of AF nor its response to therapy are sufficiently predictable by clinical and echocardiographic parameters. Atrial fibrillatory frequency (or rate) can reliably be assessed from the surface electrocardiogram (ECG) using digital signal processing (filtering, subtraction of averaged QRST complexes, and power spectral analysis) and shows large inter-individual variability. This measurement correlates well with intraatrial cycle length, a parameter which appears to have primary importance in AF domestication and response to therapy. AF with a low fibrillatory rate is more likely to terminate spontaneously, and responds better to antiarrhythmic drugs or cardioversion while high rate AF is more often persistent and refractory to therapy. In conclusion, frequency analysis of AF seems to be useful for non-invasive assessment of electrical remodeling in AF and may subsequently
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| 18. |
- Husser, Daniela, et al.
(författare)
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PR interval associated genes, atrial remodeling and rhythm outcome of catheter ablation of atrial fibrillation-A gene-based analysis of GWAS data
- 2017
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Ingår i: Frontiers in Genetics. - : Frontiers Media SA. - 1664-8021. ; 8:DEC
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Tidskriftsartikel (refereegranskat)abstract
- Background: PR interval prolongation has recently been shown to associate with advanced left atrial remodeling and atrial fibrillation (AF) recurrence after catheter ablation. While different genome-wide association studies (GWAS) have implicated 13 loci to associate with the PR interval as an AF endophenotype their subsequent associations with AF remodeling and response to catheter ablation are unknown. Here, we perform a gene-based analysis of GWAS data to test the hypothesis that PR interval candidate genes also associate with left atrial remodeling and arrhythmia recurrence following AF catheter ablation. Methods and Results: Samples from 660 patients with paroxysmal (n = 370) or persistent AF (n = 290) undergoing AF catheter ablation were genotyped for ~1,000,000 SNPs. Gene-based association was investigated using VEGAS (versatile gene-based association study). Among the 13 candidate genes, SLC8A1, MEIS1, ITGA9, SCN5A, and SOX5 associated with the PR interval. Of those, ITGA9 and SOX5 were significantly associated with left atrial low voltage areas and left atrial diameter and subsequently with AF recurrence after radiofrequency catheter ablation. Conclusion: This study suggests contributions of ITGA9 and SOX5 to AF remodeling expressed as PR interval prolongation, low voltage areas and left atrial dilatation and subsequently to response to catheter ablation. Future and larger studies are necessary to replicate and apply these findings with the aim of designing AF pathophysiology-based multi-locus risk scores.
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| 19. |
- Husser, Daniela, et al.
(författare)
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Validation and clinical application of time-frequency analysis of atrial fibrillation electrocardiograms
- 2007
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 18:1, s. 41-46
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Fibrillatory rates can reliably be obtained from surface ECGs during atrial fibrillation (AF) and correspond with right atrial (RA) and coronary sinus (CS) rates, while both the relation with pulmonary venous (PV) rates and determinants of fibrillatory waveform are unknown. Class III antiarrhythmic drugs prolong atrial refractoriness and decrease its dispersion, effects that may be reflected in ECG parameters. Consequently, this study sought (1) to investigate the relation between ECG fibrillatory rate and waveform characteristics with intraatrial/PV fibrillatory activity and (2) to noninvasively monitor class III antiarrhythmic drug effects in patients with AF. Methods and Results: Thirty-six patients with drug-refractory AF who underwent catheter-based pulmonary vein isolation and had AF at the beginning of the procedure were studied. A positive correlation between V1 rates obtained by time-frequency analysis and RA (R = 0.97, P < 0.001), CS (R = .71, P < 0.001), and PV rates (R = 0.65, P = 0.001) was found. Exponential decay defined as decay of the curve that connects power maxima of dominant and harmonic frequency components correlated with RA rate dispersion (R = 0.53, P = 0.004). In amiodarone-treated patients (n = 7), V1 rate (286 +/- 64 vs. 371 +/- 40 fpm, P < 0.001) and exponential decay (1.06 +/- 0.29 vs. 1.38 +/- 0.38, P = 0.034) were lower than in patients without amiodarone (n = 29). In 19 additional patients with persistent AF, oral dofetilide treatment decreased mean fibrillatory rate from 377 +/- 57 to 294 +/- 50 fpm (P < 0.001) and exponential decay from 1.24 +/- 0.43 to 0.85 +/- 0.22 (P = 0.002). Conclusions: Fibrillatory waves of surface ECG lead V1 closely reflect right atrial, and, to a lesser degree, left atrial activity. Time-frequency analysis allows noninvasive monitoring of antiarrhythmic drug effects on fibrillatory rate and waveform.
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| 20. |
- Husser, Oliver, et al.
(författare)
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Exercise testing for non-invasive assessment of atrial electrophysiological properties in patients with persistent atrial fibrillation
- 2007
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Ingår i: Europace. - : Oxford University Press (OUP). - 1532-2092. ; 9:8, s. 627-632
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Tidskriftsartikel (refereegranskat)abstract
- Aims Experimental studies suggest that the autonomic nervous system modulates atrial refractoriness and conduction velocity in atrial. fibrillation (AF). These modulatory effects are, however, difficult to assess in the clinical setting. This study sought to non-invasively characterize in patients with persistent AF, the influence of autonomic modulation induced by exercise on atrial fibrillatory rate as marker of atrial refractoriness and to identify clinical and electrocardiographic predictors of atrial rate response. Methods and results In 24 patients (16 mates, mean age 60 +/- 13 years) with persistent AF (16 +/- 25 months), continuous ECGs were recorded during bicycle exercise testing. Fibrillatory rate (in fibrillations per minute, fpm) was assessed at baseline and immediately after termination of exercise with spatiotemporal QRST cancellation and time-frequency analysis. Ventricular response was characterized by time-domain HRV indices. Exercise had no influence on mean fibrillatory rate (409 +/- 42 vs. 414 +/- 43 fpm, P = NS). Seven patients responded to exercise with an increase in fibrillatory rate (26 10 fpm, P < 0.001 and three with a decrease (-21 +/- 8 fpm, P < 0.001), while the remaining 14 patients did not show a response. Responders' HRV indices changed in response to exercise similarly to that of non-responders. Their baseline fibrillatory rate was, however, lower than that of non-responders (387 +/- 18 vs. 425 +/- 48 fpm, P = 0.028). No other clinical or echocardiographic variable was associated with fibrillatory rate response. Twelve weeks after cardioverson, responders were more likely to remain in sinus rhythm than non-responders (88 vs. 46 %, P = 0.04). Conclusions Exercise-induced autonomic activation produces changes in atrial. etectrophysiological properties that can be detected by time-frequency analysis. Higher baseline fibrillatory rates are associated with an impaired atrial response to exercise that suggests advanced electrical remodelling and reduced sensitivity to autonomic stimuli.
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| 21. |
- Husser, O., et al.
(författare)
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Exercise testing for non-invasive assessment of atrial electrophysiology in patients with persistent atrial fibrillation
- 2006
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Ingår i: 2006 Computers in Cardiology, CIC. - 1424425328 - 9781424425327 ; 33, s. 21-24
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Konferensbidrag (refereegranskat)abstract
- The abstract with its heading should not be more than 75 mm long. This is equivalent to 18 lines of text. Leave 1 line space at the bottom of the abstract before continuing with the next heading. The autonomic nervous system modulates atrial electrophysiology in atrial fibrillation (AF). The purpose of this study was (1) to non-invasively characterize the effects of exercise on atrial fibrillatory rate as marker of atrial refractoriness in patients with persistent AF and (2) to identify clinical and electrocardiographic predictors for rate response. In 15 patients with persistent AF, mean fibrillatory rate assessed by spatiotemporal QRST cancellation and time-frequency analysis remained unchanged with exercise. There were, however, 6 responders (rate change > 2.5%), with either a rate increase (N=5, 25±9 fpm) or decrease (N=1, -13 fpm). Absolute fibrillatory rate change (%) correlated inversely with baseline fibrillatory rate (r= -0.543, p=.045). In conclusion, sympathetic activation by exercise modulates atrial electrophysiology in some patients which can be monitored using time-frequency analysis. Higher baseline fibrillatory rates are associated with less autonomic modulation indicating advanced electrical remodeling.
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| 22. |
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| 23. |
- Linz, Dominik, et al.
(författare)
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Twitter for professional use in electrophysiology : practical guide for #EPeeps
- 2021
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Ingår i: Europace. - : Oxford University Press. - 1099-5129 .- 1532-2092. ; 23:8, s. 1192-1199
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Forskningsöversikt (refereegranskat)abstract
- Social media (SoMe) becomes more and more popular in the cardiological community. Among them, Twitter is an emerging and dynamic medium to connect, communicate and educate academic and clinical cardiologists. However, in contrast to traditional scientific communications, the content provided through SoMe is not peer-reviewed and may not necessarily always represent scientific evidence or may even be used to unjustifiably promote therapies for commercial purposes. For the unintended, this means of communication might be appear difficult to handle. This article aims to provide a practical guide on how to use Twitter efficiently for professional use to keep yourself up-to-date about new techniques, the Latest study results and news presented at national or international conferences. Additionally, important limitations will be discussed.
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| 24. |
- Norhammar, Anna, et al.
(författare)
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Prevalence, outcomes and costs of a contemporary, multinational population with heart failure
- 2023
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Ingår i: Heart. - : BMJ Publishing Group Ltd. - 1355-6037 .- 1468-201X. ; 109:7, s. 548-556
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Tidskriftsartikel (refereegranskat)abstract
- Objective; Digital healthcare systems could provide insights into the global prevalence of heart failure (HF). We designed the CardioRenal and Metabolic disease (CaReMe) HF study to estimate the prevalence, key clinical adverse outcomes and costs of HF across 11 countries.Methods: Individual level data from a contemporary cohort of 6 29 624 patients with diagnosed HF was obtained from digital healthcare systems in participating countries using a prespecified, common study plan, and summarised using a random effects meta-analysis. A broad definition of HF (any registered HF diagnosis) and a strict definition (history of hospitalisation for HF) were used. Event rates were reported per 100 patient years. Cumulative hospital care costs per patient were calculated for a period of up to 5 years.Results: The prevalence of HF was 2.01% (95% CI 1.65 to 2.36) and 1.05% (0.85 to 1.25) according to the broad and strict definitions, respectively. In patients with HF (broad definition), mean age was 75.2 years (95% CI 74.0 to 76.4), 48.8% (40.9-56.8%) had ischaemic heart disease and 34.5% (29.4-39.6%) had diabetes. In 51 442 patients with a recorded ejection fraction (EF), 39.1% (30.3-47.8%) had a reduced, 18.8% (13.5-24.0%) had a mildly reduced and 42.1% (31.5-52.8%) had a preserved left ventricular EF. In 1 69 518 patients with recorded estimated glomerular filtration rate, 49% had chronic kidney disease (CKD) stages III-V. Event rates were highest for cardiorenal disease (HF or CKD) and all cause mortality (19.3 (95% CI 11.3 to 27.1) and 13.1 (11.1 to 15.1), respectively), and lower for myocardial infarction, stroke and peripheral artery disease. Hospital care costs were highest for cardiorenal diseases.Conclusions: We estimate that 1-2% of the contemporary adult population has HF. These individuals are at significant risk of adverse outcomes and associated costs, predominantly driven by hospitalisations for HF or CKD. There is considerable public health potential in understanding the contemporary burden of HF and the importance of optimising its management.
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