| 1. |
- 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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| 2. |
- Bollmann, A, et al.
(författare)
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Frequency measures obtained from the surface electrocardiogram in atrial fibrillation research and clinical decision-making
- 2003
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 14:s10, s. 154-161
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Tidskriftsartikel (refereegranskat)abstract
- Frequency Measures in AF. Introduction: Frequency analysis of fibrillation (FAF) and time-frequency analysis (TFA) were developed recently in order to quantify atrial electrical remodeling in atrial fibrillation (AF) from the surface ECG. This article describes the experience with these two different frequency analysis techniques in consecutive AF patients and discusses possible applications in AF research and clinical decision-making. Methods and Results: Baseline 2-minute, high-gain, high-resolution ECG recordings using three bipolar leads were obtained from 80 consecutive patients with AF lasting >24 hours. A power spectrum was obtained using Fourier analysis following spatiotemporal QRST cancellation. The dominant fibrillatory rate (in fibrillations per minute [fpm]) was derived (FAF). Stability of the instantaneous fibrillatory rate measured in overlapping 1-second segments was expressed as the segment proportion with consecutive rate differences <6 fpm (TFA). An adequate power spectrum that could be submitted for determination of fibrillatory rate was obtained in all patients. Dominant atrial rates ranged between 288 and 534 fpm and showed a high correlation (R = 0.878-0.911, P < 0.001) when assessed from the three different leads. The average instantaneous fibrillatory rate was inversely related with its stability (R = -0.417, P < 0.001). It was closely related with the dominant fibrillatory rate obtained from FAF (R = 0.948, P < 0.001). A literature review revealed that pharmacologic or electrical cardioversion and AF pace termination success rates were highly dependent on fibrillatory rate. Conclusion: Atrial fibrillatory rate and its variability can be reliable obtained from the surface ECG in AF patients. These parameters exhibit a significant interindividual variability allowing individual quantification of the atrial electrical remodeling process and might prove useful for predicting therapy efficacy.
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| 3. |
- Carlson, Jonas, et al.
(författare)
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Left Atrial Conduction along the Coronary Sinus during Ectopic Atrial Tachycardia and Atrial Fibrillation: A Study Using Correlation Function Analysis
- 2003
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 14:10 Suppl, s. 148-153
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Tidskriftsartikel (refereegranskat)abstract
- ntroduction: Correlation function analysis was applied to endocardial electrograms to investigate conduction patterns along the coronary sinus (CS) during sinus rhythm (SR) and atrial tachycardias. Methods and Results: Eighteen recordings were obtained from 14 patients suffering from supraventricular tachycardias. Five atrial fibrillation(AF) recordings were compared to 10 SR recordings and 3 ectopic atrial tachycardia (EAT) recordings. The maximum correlation coefficient was used to assess similarity between signals, i.e., if they originate from the samewavefront. The cumulative time delay, calculated as pairwise summation of interelectrode time delays was used as an indicator of activation sequence along CS. Method validation using SR showed right to left conduction with high correlations in 8 of 10 recordings indicating one single wavefront. EAT recordings showed consistent left to right conduction with left atrial foci and right to left with right atrial focus and lower correlations than SR. All 5 AFrecordings showed predominantly left to right conduction direction, also with correlations lower than SR.Conclusion: 1) Correlation function analysis can be used to assess agreement between signals and direction of activation spread. 2) Due to the position of CS, the results can be used to derive mechanisms of interatrial conduction. 3) Consistency in electrical activity propagation along CS iscommon in AF.
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| 4. |
- 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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| 5. |
- Liu, SW, et al.
(författare)
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Concealed conduction and dual pathway physiology of the atrioventricular node
- 2004
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 15:2, s. 144-149
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Tidskriftsartikel (refereegranskat)abstract
- AV Nodal Duality and Concealment. Introduction: Both concealed conduction and dual pathway physiology are important electrophysiologic characteristics of the AV node. The interaction of AV nodal concealment and duality, however, is not clearly understood. Methods and Results: The properties of AV conduction curves in the presence and absence of a conditioning blocked impulse were prospectively studied during premature atrial stimulation in 20 patients with AV nodal reentrant tachycardia before and after slow pathway ablation and in 14 control patients. AV nodal duality in the control conduction curve in the absence of a conditioning impulse was observed in 19 (95%) of 20 patients with AV nodal reentrant tachycardia. However, AV nodal duality in the modulated conduction curve in the presence of a blocked impulse was only identified in 2 (10%) of 20 patients (2/20 vs 19/20, P < 0.0001). The modulated curve was characterized by a significantly longer AV nodal effective and functional refractory periods compared to the control curve (P < 0.0001) in both patients with and without AV nodal reentry and in AV nodal reentry patients after successful slow pathway ablation. The maximum AH interval (AH(max)) of the modulated curve was significantly shorter than the control curve in both patients with (217 +/- 74 ms vs 347 +/- 55 ms, P < 0.0001) and without AV nodal reentry (178 +/- 50 ms vs 214 +/- 54 ms, P = 0.02). AH(max) of the control curve was significantly longer in AV nodal reentry patients than in controls (P < 0.0001). AH(max) of the modulated curve, however, was not significantly different between the two groups. After slow pathway ablation, AHmax of the control curve was significantly reduced (347 +/- 55 ms vs 191 +/- 40 ms, P < 0.0001). Significant reduction in AH(max) of the modulated curve was not observed. Conclusion: An interaction of AV nodal concealed conduction and dual pathway physiology was demonstrated by our data. Slow pathway conduction of the AV node was prevented by the concealed beat in both patients with and without AV nodal reentry.
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| 6. |
- Platonov, Pyotr, et al.
(författare)
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Left atrial appendage activity translation in the standard 12-lead ECG
- 2011
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 22:6, s. 706-710
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedLAA Activity in Surface ECG. Introduction: Interatrial frequency gradient is used to guide catheter ablation of atrial fibrillation (AF). Lead V1 adequately reflects right atrial activity, but reliable tools for noninvasive estimation of right versus left fibrillatory frequency are lacking. In this study, patients with dissociated left and right atrial rhythms were studied in order to identify which surface electrocardiographic (ECG) leads that most closely reflect the left atrial activity.Methods: Two consecutive patients with atrial tachycardia confined to the left atrial appendage (LAA) detected during catheter ablation of AF were included (2 men, 54 and 72 years old). A 12-lead ECG was recorded simultaneously with electrograms from the right and left atrial appendages (RAA/LAA). AF frequency spectra were calculated from all 12 leads using spatiotemporal QRST cancellation and Welch periodogram. The dominating atrial cycle length (DACL) in the surface ECG leads was subsequently compared with the invasively measured LAA cycle length.Results: LAA activation frequency was seen as a prominent peak in the frequency–power spectrum derived from frontal plane leads as well as lead V1. The absolute difference in noninvasively and invasively measured LAA cycle length was lowest for leads aVR, II, aVF, III, and V1 in which it was in the range of 2–4 ms.Conclusion: Prominent left atrial component is present in the majority of standard ECG leads, including those traditionally associated with right atrial activity such as V1. Spectral analysis is able to extract the LAA component on surface ECG.
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| 7. |
- Platonov, Pyotr, et al.
(författare)
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Left Atrial Posterior Wall Thickness in Patients with and without Atrial Fibrillation: Data from 298 Consecutive Autopsies.
- 2008
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 19:7, s. 689-692
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Radiofrequency ablation of atrial fibrillation (AF) is associated with energy delivery on the posterior left atrial (LA) wall with small but significant risk of life-threatening complications. Anatomy of LA walls has been described, but wall thickness in patients with AF has not been studied systematically. The aim of the present study was to describe LA posterior wall thickness in patients with and without history of AF. Methods and Results: Heart mass and LA wall thickness was measured during 298 consecutive autopsies (142 male, age 61 +/- 17 years). LA posterior wall was measured at three levels: between the superior pulmonary veins (SPV), in the center of the posterior LA wall (CPV), and between the inferior pulmonary veins (IPV). Information about AF history was obtained from medical records. Fifty-nine subjects (20%) had documented AF. They were older than subjects without AF (74 +/- 10 years vs 58 +/- 17 years, P < 0.0001) and had greater heart mass (522 +/- 114 g vs 389 +/- 99 g, P < 0.0001). LA posterior wall thickness increased from the most superior to the most inferior measured level (2.3 +/- 0.9 mm vs 2.5 +/- 1.0 mm vs 2.9 +/- 1.3 mm for SPV, CPV, and IPV, respectively; P < 0.001). Subjects with AF history had thinner LA posterior wall at CPV and IPV compared with those without AF. Conclusions: LA posterior wall thickness is described on a large series of consecutive autopsies. LA posterior wall is found to be generally thinner in patients with history of AF. Study results have clinical implications for understanding complication risk and improvement of safety of AF ablation procedures.
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| 8. |
- Yuan, S, et al.
(författare)
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Monophasic action potentials : concepts to practical applications
- 1994
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Ingår i: Cardiovascular Electrophysiology. - : Wiley. - 1045-3873 .- 1540-8167. ; 5:3, s. 287-308
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Tidskriftsartikel (refereegranskat)abstract
- Monophasic Action Potentials. Monophaisc action potential (MAP) recordings reproduce the repolarization time course of intrucellular action potentials with high accuracy and provide precise information on the local activation time. With the advantage of in vivo application and the development of the safer and simpler contact catheter technique, MAP recording has become the method of choice for evaluating myocardial repolarization changes. This review aims to provide information on practical application of MAP recording in the clinical setting. MAPs can easily be recorded from the endocardium with the contact catheter technique in the electrophysiology laboratory and from the epicardium with electrode probes during open heart surgery. The technical aspects are described in detail. The rate dependence of myocardial excitability and repolarization and the effect of antiarrhythmic drugs on MAP duration and effective refractory period are thoroughly reviewed. The use of MAPs in detecting myocardial ischemia, in studying early afterdepolarization and triggered arrhythmias, in measuring dispersion of repolarization, in identifying intracardiac conduction and the development of the T wave, and in verifying the arrhythmogenic effect of mechanoelectric feedback are presented. Computerized automatic analysis of MAPs and the limitations of the MAP technique are also discussed.
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| 9. |
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| 10. |
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| 11. |
- Boriani, Giuseppe, et al.
(författare)
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Plateau waveform shape allows a much higher patient shock energy tolerance in AF patients.
- 2007
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Ingår i: Journal of cardiovascular electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 18:7, s. 728-34
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- OBJECTIVES: To evaluate the possible pain reduction of the plateau waveform in atrial fibrillation (AF) patients. BACKGROUND: Previous studies have indicated that reduced amplitude waveforms would be less painful than a conventional (65/65% tilt) biphasic waveform. Computer modeling suggested that a moderately long (10-12 msec) plateau (flat topped) shock waveform would deliver equivalent effectiveness with the lowest possible peak amplitude. METHODS: We enrolled 27 patients at two sites with persistent AF with a total of 220 shocks delivered during internal atrial cardioversion using an interleaved crossover design. Patient response was scored in three ways: (1) a verbally reported discomfort score, (2) visual analog scale (VAS), and (3) a blinded observer reporting a contraction score. RESULTS: All scores were significantly reduced (P < 0.0001) by the plateau waveform with impressive statistics: Verbal discomfort (3.51 +/- 0.13 to 2.89 +/- 0.12), VAS (7.00 +/- 0.56 to 5.91 +/- 0.36), and contraction scores (1.94 +/- 0.12 to 1.62 +/- 0.12). The average pain threshold shift (TS) for the Verbal score was 2.34, while that for the VAS score was 2.30. (This means that the patient typically could tolerate 2.34 times as much energy with the plateau waveform for the same level of verbally reported discomfort.) The contraction TS was less at 1.57. Response scores were also corrected for the shock sequence number to control for the sensitization effect from multiple shocks. This increased the TS for the Verbal score to 3.58, but the shock number was not significant for the VAS. A pulmonary artery electrode return was associated with lower pain compared with a coronary sinus position. CONCLUSION: A plateau shaped biphasic waveform resulted in significantly increased shock energy pain tolerances. Controlling for session sensitization, patients tolerated over three times as much energy for the same verbally reported discomfort score.
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| 15. |
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| 18. |
- Jais, Pierre, et al.
(författare)
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Stepwise catheter ablation of chronic atrial fibrillation : Importance of descrete anatomic sites for termination
- 2006
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 17:Suppl 3, s. 28-36
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chronic atrial fibrillation (CAF) can be acutely terminated using a combination of approaches targeting thoracic veins, left atrial areas showing rapid/heterogeneous electrical activity, and by linear ablation. This observational study emphasizes the crucial role for conventional endocardial mapping to identify discrete anatomical sites, ablation of which is indispensable for the achievement of atrial fibrillation (AF) termination. Methods: Eighty consecutive patients with CAF underwent catheter ablation using the stepwise approach. Pulmonary vein isolation and roof-line ablation were performed as the initial two steps in all patients. In the presence of locally rapid or heterogeneous activity, ablation was then performed at all sites within the left atrium and coronary sinus (CS) region with the endpoint of local organization or slowing. If AF persisted, the mitral isthmus was targeted. Patients in whom AF terminated during one of these five ablation steps were differentiated from those in whom AF was terminated by radiofrequency ablation at a single discrete anatomic site within 1 minute. Electrograms at discrete anatomic sites of termination were classified according to morphology. Results: Termination of AF was achieved in 69 (86%) patients by ablation alone. In 50 patients (72%), this occurred while following the predetermined ablation schema. In the remaining 19 patients (28%), ablation targeting a discrete site (preferentially located at the CS, the base of left atrial appendage, and the interatrial septum) terminated AF. Such sites were identified by (1) continuous electrical activity and fractionation and (2) bursts of short cycle activity (130–160 msec), centrifugal activation or local activation gradients, indicating sources perpetuating AF. Conclusion: In 28% of patients with termination of CAF, the final successful ablation site is anatomically discrete and displays electrophysiological characteristics that can be effectively identified by point and activation mapping. Failure to identify these sites may significantly reduce the likelihood of termination of CAF by catheter ablation.
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| 19. |
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| 21. |
- Rostock, Thomas, et al.
(författare)
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Fibrillating areas isolated within the left atrium after radiofrequency linear catheter ablation
- 2006
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Ingår i: Cardiovascular Electrophysiology. - : Wiley. - 1045-3873 .- 1540-8167. ; 17, s. 807-812
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Nonpulmonary vein sources have been implicated as potential drivers of atrial fibrillation (AF). This observational study describes regions of fibrillating atrial tissue isolated inadvertently from the left atrium (LA) following linear catheter ablation for AF. METHODS AND RESULTS: We report four patients with persistent/permanent AF who underwent pulmonary vein isolation with additional linear lesions and who presented with recurrent AF (mean AF cycle length [AFCL] 175-270 ms). Further catheter ablation resulted in the inadvertent electrical isolation of significant areas of the LA in which AF persisted at the same AFCL as was measured prior to disconnection, despite the restoration of sinus rhythm (SR) in all other left and right atrial areas, strongly suggesting that these islands were driving the remaining atria into fibrillation. The disconnected areas were located in the lateral LA, including the left atrial appendage (LAA) in three patients (limited to the LAA in one) and in the posterior LA in one patient. These isolated fibrillating regions represented 15-24% of the global LA surface, as estimated by electroanatomic mapping. CONCLUSION: Fibrillation can be maintained within electrically isolated regions of the LA following catheter ablation of AF, demonstrating the importance of atrial drivers in the maintenance of AF. Further mapping of these drivers is needed to characterize their mechanism and thereby allow for a more specific ablation strategy.
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| 22. |
- Sanders, Prashanthan, et al.
(författare)
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Frequency mapping of the pulmonary veins in paroxysmal versus permanent atrial fibrillation
- 2006
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1540-8167 .- 1045-3873. ; 17, s. 965-972
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The pulmonary veins (PVs) are a dominant source of triggers initiating atrial fibrillation (AF). While recent evidence implicates these structures in the maintenance of paroxysmal AF, their role in permanent AF is not known. The current study aims to compare the contribution of PV activity to the maintenance of paroxysmal and permanent AF. METHODS AND RESULTS: Thirty-four patients with paroxysmal AF (n = 20) or permanent AF (n = 14) undergoing ablation were studied. Prior to ablation, 32 seconds of electrograms were acquired from each PV and the coronary sinus (CS). The frequency of activity of each PV and CS was defined as the highest amplitude frequency on spectral analysis. The effects of ablation on the AF cycle length (AFCL) and frequency and on AF termination were determined. Significant differences were observed between paroxysmal and permanent AF. Paroxysmal AF demonstrates higher frequency PV activity (11.0 +/- 3.1 vs 8.8 +/- 3.0 Hz; P = 0.0003) but lower CS frequency (5.8 +/- 1.2 vs 6.9 +/- 1.4 Hz; P = 0.01) and longer AFCL (182 +/- 17 vs 158 +/- 21 msec; P = 0.002), resulting in greater PV to atrial frequency gradient (7.2 +/- 2.2 vs 4.2 +/- 2.9 Hz; P = 0.006). PV isolation in paroxysmal AF resulted in a greater decrease in atrial frequency (1.0 +/- 0.7 vs -0.05 +/- 0.4 Hz; P < 0.0001), greater prolongation of the AFCL (49 +/- 35 vs 5 +/- 6 msec; P < 0.0001), and more frequent AF termination (11/20 vs 0/14; P = 0.0007) compared to permanent AF. CONCLUSION: Paroxysmal AF is associated with higher frequency PV activity and lesser CS frequency compared to permanent AF. Isolation of the PVs had a greater impact on the fibrillatory process in paroxysmal AF compared to permanent AF, suggesting that while the PVs have a role in maintaining paroxysmal AF, these structures independently contribute less to the maintenance of permanent AF
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