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| 2. |
- Gottfridsson, Christer, 1958, et al.
(författare)
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Acute evaluation of transthoracic impedance vectors using ICD leads.
- 2009
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Ingår i: Pacing and clinical electrophysiology : PACE. - : Wiley. - 1540-8159 .- 0147-8389. ; 32:6, s. 762-71
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Minute ventilation (MV) has been proven to be very useful in rate responsive pacing. The aim of this study was to evaluate the feasibility of using implantable cardioverter-defibrillator (ICD) leads as part of the MV detection system. METHODS: At implant in 10 patients, the transthoracic impedance was measured from tripolar ICD, tetrapolar ICD, and atrial lead vectors during normal, deep, and shallow voluntary respiration. MV and respiration rate (RespR) were simultaneously measured through a facemask with a pneumotachometer (Korr), and the correlations with impedance-based measurements were calculated. Air sensitivity was the change in impedance per change in respiratory tidal volume, ohms (Omega)/liter (L), and the signal-to-noise ratio (SNR) was the ratio of the respiratory and cardiac contraction components. RESULTS: The air sensitivity and SNR in tripolar ICD vector were 2.70 +/- 2.73 ohm/L and 2.19 +/- 1.31, respectively, and were not different from tetrapolar. The difference in RespR between tripolar ICD and Korr was 0.2 +/- 1.91 breaths/minute. The regressed correlation coefficient between impedance MV and Korr MV was 0.86 +/- 0.07 in tripolar ICD. CONCLUSIONS: The air sensitivity and SNR in tripolar and tetrapolar ICD lead vectors did not differ significantly and were in the range of the values in pacemaker leads currently used as MV sensors. The good correlations between impedance-based and Korr-based RespR and MV measurements imply that ICD leads may be used in MV sensor systems.
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| 3. |
- Holmqvist, Fredrik, et al.
(författare)
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Indices of electrical and contractile remodeling during atrial fibrillation in man
- 2006
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 29:5, s. 512-519
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Tidskriftsartikel (refereegranskat)abstract
- Atrial electrical and contractile remodeling have been demonstrated to coincide during atrial fibrillation (AF) in experimental studies. We explored whether electrical and contractile remodeling correlate in man and explored its clinical implications. METHODS: Forty-nine patients with persistent AF were studied. Electrical remodeling was assessed noninvasively using spectral analysis to estimate the average fibrillatory rate (AFR). Atrial contractility was assessed by transesophageal echocardiography (TEE) measurement of left atrial appendage outflow velocity (LAAOV). RESULTS: The AFR was 403+/-43 fibrillations per minute (fpm) and the LAAOV was 0.27+/-0.14 m/s. A significant correlation was found between AFR and LAAOV (r=-0.47, P=0.001). In patients with a LAAOV>or=0.25 m/s, the AFR was 387+/-48 fpm compared to 419+/-31 fpm among patients with LAAOV<0.25 m/s (P<0.01). CONCLUSIONS: This study demonstrates that indices of electrical and contractile remodeling are strongly correlated in persistent AF in man. The interindividual overlap, however, is too large to allow predictions of LAAOV based on fibrillatory frequency alone.
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| 4. |
- Holmqvist, Fredrik, et al.
(författare)
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Noninvasive evidence of shortened atrial refractoriness during sinus rhythm in patients with paroxysmal atrial fibrillation.
- 2009
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 32:3, s. 302-307
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Shortening of the atrial refractory period is the key feature of atrial electrical remodeling during atrial fibrillation (AF). During sinus rhythm (SR), assessment of the atrial refractoriness is hampered by the fact that the atrial repolarization wave (Ta wave) is largely obscured by the following QRST complex. The purpose of this study was to study the Ta wave in subjects with paroxysmal AF during SR with third-degree atrioventricular (AV) block, and in matched controls. METHODS: Fifteen patients (mean age 70 +/- 10 years, five males) with paroxysmal AF undergoing AV-nodal ablation were studied. Fifteen age- and gender-matched subjects (mean age 71 +/- 9 years, five males) with third-degree AV block, without a history of heart disease, were used as controls. Standard 12-lead electrocardiograms (ECGs) were recorded and transformed to orthogonal leads and studied using P-wave signal averaging technique. RESULTS: The P to Ta interval was shorter (408 +/- 47 ms vs 451 +/- 53 ms, P = 0.017) and in Lead Y the Ta peak location was earlier (156 +/- 31 ms vs 187 +/- 34 ms, P = 0.002) in subjects with paroxysmal AF than in the controls. The P-wave duration (126 +/- 15 ms vs 129 +/- 17 ms, P = 0.59) and morphology was similar in AF patients and controls. CONCLUSIONS: In this study, the ECG signs of shorter atrial refractoriness associated with a history of AF are visualized for the first time during SR. The finding of the earlier location of the PTa peak in AF subjects implies that a possible indicator of increased arrhythmia susceptibility may be visible already in the unprocessed ECG.
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| 5. |
- Husser, D, et al.
(författare)
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Determinants and prognostic significance of immediate atrial fibrillation recurrence following cardioversion in patients undergoing pulmonary vein isolation
- 2005
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 28:2, s. 119-125
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Tidskriftsartikel (refereegranskat)abstract
- Background: Immediate recurrence of atrial fibrillation (IRAF) occurs frequently after electrical cardioversion, its electrophysiological determinants and prognostic significance hove, however, not been studied in detail. This Study aimed to explore (1) the association of IRAF with clinical characteristics, pulmonary vein (PV) arrhythmogenicity as well as atrial electrophysiologic properties and (2) the prognostic significance of IRAF for outcome of PV isolation for atrial fibrillation (AF). Methods and Results: The subjects of this study were 41 consecutive patients (30 males, 11 females) who underwent PV isolation for drug-refroctory AF. Following successful initial cordioversion, 19 patients (46%) had IRAF within 2 minutes. Coupling intervals of AF reinitiating beats arising from PVs were shorter (386 +/- 39 vs 490 +/- 136 ms, P=0.008) and prematurity indices (0.38 +/- 0.06 vs 0.51 +/- 0.12, P=0.01) smaller than those of premature beats not initiating AF Patients with IRAF had more frequently AF duration <1 month, a longer P-wave duration, and a longer mid coronary sinus AF cycle length. Multivariate regression analysis revealed coronary sinus AF cycle length ( beta = 0.186, P=0.049), which was closely correlated with conduction time along the coronary sinus (R = 0.716, P = 0.003) to be independently associated with IRAF While early AF recurrence rate (within the first 5 days) following the procedure was higher in the IRAF group (53 vs 18%, P = 0.02), outcome was not different between the two groups thereafter. Conclusions: (1) IRAF is common in patients undergoing PV isolotion for AF, (2) is initiated by premature atrial beats with short coupling intervals, and (3) seems to be associated with conduction disturbances along the coronary sinus. It reflects susceptibility of arrhythmia recurrence within the first 5 days after the procedure, but not thereafter.
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| 6. |
- Höijer, Carl Johan, et al.
(författare)
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Single chamber atrial pacing: A realistic option in sinus node disease: A long-term follow-up study of 213 patients
- 2007
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 30:6, s. 740-747
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Tidskriftsartikel (refereegranskat)abstract
- Background: Despite several decades of experience with atrial pacing, many centers do not apply this mode to any greater extent, mainly because of concerns for the development of future atrioventricular (AV) block or atrial fibrillation. Recent studies have emphasized possible negative effects of right ventricular stimulation, even when AV-synchrony is preserved, and have thus given rise to renewed interest in single chamber atrial pacing for sinus node disease. Methods: This study presents the results of up to 19 years' follow-up of 213 patients with sinus node disease treated with atrial pacing with respect to survival and causes of death, development of atrial fibrillation and AV block, and total mode survival. Patients were divided into two groups: with or without associated atrial tachyarrhythmias at the time of implant. Results are given for all patients and for the two groups separately. Results: The mean follow-up time was 10.1 years. The survival of the entire group was lower after 10 years than that of an age and gender-matched general Swedish population. This was caused by patients with the brady-tachy syndrome (BT) having a significantly higher mortality rate than controls, whereas those with bradycardia only (B) had survival comparable to the general population. Permanent atrial fibrillation (AF) developed in 20% of patients and was significantly more common in patients with BT. The majority of patients with AF (78%) no longer needed any pacing, i.e., did not require ventricular stimulation due to slow ventricular rate. The annual incidence of high grade AV block was 1.8%. If patients with preexisting bundle branch block were excluded, the incidence was 1.6%. No fatal episode of AV block was seen. The overall mode survival at the end of follow-up was 75%, with 155 patients still with atrial pacemakers. Conclusion: Atrial pacing is a safe and reliable mode of pacing in patients with sinus node disease, even in the very long-term.
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| 7. |
- Jensen, Steen, et al.
(författare)
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Syncope and wide QRS tachycardia.
- 2005
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Ingår i: Pacing Clin Electrophysiol. - : Wiley. - 0147-8389. ; 28:7, s. 708-9
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Tidskriftsartikel (refereegranskat)
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| 8. |
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| 9. |
- Kesek, Milos, et al.
(författare)
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U22, a protocol to quantify symptoms associated with supraventricular tachycardia.
- 2009
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Ingår i: Pacing and Clinical Electrophysiology. - : Wiley. - 0147-8389 .- 1540-8159. ; 32:S1, s. S105-S108
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The main indication for ablation of supraventricular tachyarrhythmias (SVTA) is symptomatic relief. Specific paroxysmal symptoms cannot be quantified with general measures of quality of life, such as with the SF-36 questionnaire. U22 is a new protocol which measures the effects of arrhythmia on well-being, the intensity of discomfort during an episode, the type and temporal characteristics of dominant symptoms, and the duration and frequency of episodes. Discrete 0-10 scales are used. Unlike SF-36, U22 can be used in individual patients. METHODS: U22 and SF-36 protocols were used in the symptomatic evaluation of 88 patients (mean age = 49.6 +/- 16.4 years; 43 men), who underwent catheter ablation of SVTA. Results: The U22 scores (SD) for (a) well-being (10 being best), (b) effects of arrhythmia on well-being (10 being worst), and (c) discomfort during arrhythmia (10 being worst) were 5.6 (2.7), 7.5 (2.8), and 8.0 (2.4), respectively. For comparison, the physical and mental component summaries of SF-36 were 45.3 (11.0) and 45.2 (12.1), respectively, slightly lower than the expected normal of 50. The intensity of dominant symptom scored by U22 was 9.7 (1.2), 10 being worst. In 29% of patients > or =4 symptoms were equally dominant. Multiple dominant symptoms in U22 were associated with a low general well-being in SF-36. CONCLUSION: We found U22 useful to quantify symptoms associated with SVTA.
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| 10. |
- Milasinovic, G, et al.
(författare)
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Reduction of RV pacing by continuous optimization of the AV interval
- 2006
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Ingår i: PACE. - : Wiley. - 1540-8159. ; 29:4, s. 406-412
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Tidskriftsartikel (refereegranskat)abstract
- Background: In patients requiring permanent pacing, preservation of intrinsic ventricular activation is preferred whenever possible. The Search AV+ (SAV+) algorithm in Medtronic EnPulse(TM) dual-chamber pacemakers can increase atrioventricular (AV) intervals to 320 ms in patients with intact or intermittent AV conduction. This prospective, multicenter study compared the percentage of ventricular pacing with and without AV interval extension. Methods: Among 197 patients enrolled in the study, the percentage of ventricular-paced beats was evaluated via device diagnostics at the 1-month follow-up. Patient cohorts were defined by clinician assessment of conduction via a 1:1 AV conduction test at the 2-week follow-up. The observed percentage of ventricular pacing with SAV + ON and the predicted percentage of ventricular pacing with SAV + OFF were determined from the SAV + histogram data for the period between the 2-week and 1-month follow-up visits. Results: Of 197 patients, 110 (55.8%) had intact 1:1 AV conduction, of which 109 had 1-month data. SAV + remained ON in 991109 patients; 10 patients had intrinsic A-V conduction intervals beyond SAV + nominal and therefore SAV + disabled. The mean percentage of ventricular pacing in the 109 patients was SAV+ ON = 23.1% (median 3.7%) versus SAV + OFF = 97.2% (median 99.7%). In 87 patients without 1:1 AV conduction, SAV + was programmed OFF in 6, automatically disabled in 52, and remained ON in 29. In 8 of these patients, 80-100% reduction in ventricular pacing was observed with SAV + ON. Conclusion: The Search AV+ algorithm in the EnPulse pacemaker effectively promotes intrinsic ventricular activation and substantially reduces unnecessary ventricular pacing.
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