Factors associated with premature ventricular contraction-induced cardiomyopathy (PVCi-CMP) remain debated.
The purpose of this study was to test the correlation of various factors to the presence ...PVCi-CMP in a large multicenter population.
One hundred sixty-eight consecutive patients referred for ablation of frequent premature ventricular contractions (PVCs) were included. Patients were divided into 2 groups: group 1 with suspected PVCi-CMP (96 patients, ejection fraction 38% ± 10%, left ventricular end-diastolic diameter 62 ± 8 mm, with or without additional structural heart disease); and group 2 (control group, 72 patients with normal ejection fraction and left ventricular dimensions). Various clinical and electrophysiologic parameters were compared between groups.
In univariate analysis, left ventricular origin of PVC, lack of palpitations, long PVC coupling interval, epicardial origin of the focus, long sinus beat QRS duration, male gender, high PVC burden, presence of polymorphic PVCs, high PVC QRS duration, and older age were significantly related to the presence of PVCi-CMP. In multivariate analysis, only lack of palpitations, PVC burden, and epicardial origin remained significantly and independently correlated with the presence of cardiomyopathy. Even if sinus QRS duration or PVC left ventricular origin were also found independently linked to PVCi-CMP in the whole population, they were no longer correlated when patients with additional heart disease were excluded.
Lack of palpitations, PVC burden, and epicardial origin are independent factors that identify patients prone to developing PVCi-CMP.
Abstract Background The underlying mechanisms sustaining human persistent atrial fibrillation (PsAF) is poorly understood. Objectives This study sought to investigate the complexity and distribution ...of AF drivers in PsAF of varying durations. Methods Of 135 consecutive patients with PsAF, 105 patients referred for de novo ablation of PsAF were prospectively recruited. Patients were divided into 3 groups according to AF duration: PsAF presenting in sinus rhythm (AF induced), PsAF <12 months, and PsAF >12 months. Patients wore a 252-electrode vest for body surface mapping. Localized drivers (re-entrant or focal) were identified using phase-mapping algorithms. Results In this patient cohort, the most prominent re-entrant driver regions included the pulmonary vein (PV) regions and inferoposterior left atrial wall. Focal drivers were observed in 1 or both PV regions in 75% of patients. Comparing between the 3 groups, with longer AF duration AF complexity increased, reflected by increased number of re-entrant rotations (p < 0.05), number of re-entrant rotations and focal events (p < 0.05), and number of regions harboring re-entrant (p < 0.01) and focal (p < 0.05) drivers. With increased AF duration, a higher proportion of patients had multiple extra-PV driver regions, specifically in the inferoposterior left atrium (p < 0.01), superior right atrium (p < 0.05), and inferior right atrium (p < 0.05). Procedural AF termination was achieved in 70% of patients, but decreased with longer AF duration. Conclusions The complexity of AF drivers increases with prolonged AF duration. Re-entrant and focal drivers are predominantly located in the PV antral and adjacent regions. However, with longer AF duration, multiple drivers are distributed at extra-PV sites. AF termination rate declines as patients progress to longstanding PsAF, underscoring the importance of early intervention.
Electrocardiographic imaging is a mapping technique aiming to noninvasively characterize cardiac electrical activity using signals collected from the torso to reconstruct epicardial potentials. Its ...efficacy has been demonstrated clinically, from mapping premature ventricular complexes and accessory pathways to of complex arrhythmias. Electrocardiographic imaging uses a standardized workflow. Signals should be checked manually to avoid automatic processing errors. Reentry is confirmed in the presence of local activation covering the arrhythmia cycle length. Focal breakthroughs demonstrate a QS pattern associated with centrifugal activation. Electrocardiographic imaging offers a unique opportunity to better understand the mechanism of cardiac arrhythmias and guide ablation.
Biventricular pacing (BVP) may not achieve complete electrical resynchronization.
The purpose of this study was to assess whether the resynchronizing effect of BVP varies among patients depending on ...the underlying electrical substrate.
High-resolution electrocardiographic mapping with invasive measurement of the maximal rate of systolic left ventricular (LV) pressure rise (LVdP/dtmax) was performed during baseline activation and during BVP in 61 patients with heart failure with various conduction delays: 13 with narrow QRS duration (<120 ms), 22 with nonspecific intraventricular conduction disturbance, and 26 with left bundle branch block. Electrical dyssynchrony, both during baseline activation and BVP, was quantified by total and LV activation times (TAT and LVTAT) and by ventricular electrical uncoupling (VEU = mean LVTAT - mean right ventricular activation time). Response to BVP was defined as a ≥10% increase in LVdP/dtmax.
The electrical activation pattern during BVP was similar for all patient groups and, hence, not dependent on baseline conduction disturbance. During BVP, TAT, LVTAT, and VEU were similar for all groups and were either not correlated or weakly correlated with the change in LVdP/dtmax. In contrast, changes in electrical dyssynchrony correlated significantly with the change in LVdP/dtmax: r=0.71, 0.69, and 0.69 for ∆TAT, ∆LVTAT, and ∆VEU, respectively (all P < .001). Responders showed higher baseline dyssynchrony levels and BVP-induced dyssynchrony reduction than did nonresponders (all P < .001); in nonresponders, BVP worsened activation times than did baseline activation.
BVP does not eliminate electrical dyssynchrony, but rather brings it to a common level independent of the patient's underlying electrical substrate. Therefore, BVP is of benefit to patients with dyssynchrony but not to patients with insufficient electrical dyssynchrony in whom it induces an iatrogenic electropathy.
Risk stratification in Brugada syndrome (BS) remains controversial. The time interval between the peak and the end of the T wave (Tpe interval), a marker of transmural dispersion of repolarization, ...has been linked to malignant ventricular arrhythmias in various settings but leads to discordant results in BS.
We study the correlation of the Tpe interval with arrhythmic events in a large cohort of patients with BS.
A total of 325 consecutive patients with BS (mean age 47±13 years, 259 men-80%) with spontaneous (n=143, 44%) or drug-induced (n=182, 56%) type 1 electrocardiogram were retrospectively included. 235 were asymptomatic (70%), 80 presented with unexplained syncope (22%), and 10 presented with sudden death (SD) or appropriate implantable cardioverter-defibrillator therapy (AT) (8%) at diagnosis or over a mean follow-up of 48 ± 34 months. The Tpe interval was calculated as the difference between the QT interval and the QT peak interval as measured in each of the precordial leads.
The Tpe interval from lead V1 to lead V4, maximum value of the Tpe interval (max Tpe), and Tpe dispersion in all precordial leads were significantly higher in patients with SD/AT or in patients with syncope than in asymptomatic patients (P < .001). A max Tpe of ≥100 ms was present in 47 of 226 asymptomatic patients (21%), in 48 of 73 patients with syncope (66%), and in 22 of 26 patients with SD/AT (85%) (P < .0001). In multivariate analysis, a max Tpe of ≥100 ms was independently related to arrhythmic events (odds ratio 9.61; 95% confidence interval 3.13-29.41; P < .0001).
The Tpe interval in the precordial leads is highly related to malignant ventricular arrhythmias in this large cohort of patients with BS. This simple electrocardiographic parameter could be used to refine risk stratification.
Complex fractionated electrograms (CFAEs) detected during substrate mapping for atrial fibrillation (AF) reflect etiologies that are difficult to separate. Without knowledge of local refractoriness ...and activation sequence, CFAEs may represent rapid localized activity, disorganized wave collisions, or far-field electrograms.
The purpose of this study was to separate CFAE types in human AF, using monophasic action potentials (MAPs) to map local refractoriness in AF and multipolar catheters to map activation sequence.
MAP and adjacent activation sequences at 124 biatrial sites were studied in 18 patients prior to AF ablation (age 57 ± 13 years, left atrial diameter 45 ± 8 mm). AF cycle length, bipolar voltage, and spectral dominant frequency were measured to characterize types of CFAE.
CFAE were observed at 91 sites, most of which showed discrete MAPs and (1) pansystolic local activity (8%); (2) CFAE after AF acceleration, often with MAP alternans (8%); or (3) nonlocal (far-field) signals (67%). A fourth CFAE pattern lacked discrete MAPs (17%), consistent with spatial disorganization. CFAE with discrete MAPs and pansystolic activation (consistent with rapid localized AF sites) had shorter cycle length (P <.05) and lower voltage (P <.05) and trended to have higher dominant frequency than other CFAE sites. Many CFAEs, particularly at the septa and coronary sinus, represented far-field signals.
CFAEs in human AF represent distinct functional types that may be separated using MAPs and activation sequence. In a minority of cases, CFAEs indicate localized rapid AF sites. The majority of CFAEs reflect far-field signals, AF acceleration, or disorganization. These results may help to interpret CFAE during AF substrate mapping.
Objectives Our purpose was to evaluate the efficacy of antiarrhythmic drugs (AADs) in recurrent ventricular fibrillation (VF) associated with inferolateral early repolarization pattern on the ...electrocardiogram. Background Although an implantable cardioverter-defibrillator is the treatment of choice, additional AADs may be necessary to prevent frequent episodes of VF and reduce implantable cardioverter-defibrillator shock burden or as a lifesaving therapy in electrical storms. Methods From a multicenter cohort of 122 patients (90 male subjects, age 37 ± 12 years) with idiopathic VF and early repolarization abnormality in the inferolateral leads, we selected all patients with more than 3 episodes of VF (multiple) including those with electrical storms (≥3 VF in 24 h). The choice of AAD was decided by individual physicians. Follow-up data were obtained for all patients using monitoring with implantable defibrillator. Successful oral AAD was defined as elimination of all recurrences of VF with a minimal follow-up period of 12 months. Results Multiple episodes of VF were observed in 33 (27%) patients. Electrical storms (34 ± 47 episodes) occurred in 16 and were unresponsive to beta-blockers (11 of 11), lidocaine/mexiletine (9 of 9), and verapamil (3 of 3), while amiodarone was partially effective (3 of 10). In contrast, isoproterenol infusion immediately suppressed electrical storms in 7 of 7 patients. Over a follow-up of 69 ± 58 months, oral AADs were poorly effective in preventing recurrent VF: beta-blockers (2 of 16), verapamil (0 of 4), mexiletine (0 of 4), amiodarone (1 of 7), and class 1C AADs (2 of 9). Quinidine was successful in 9 of 9 patients, decreasing recurrent VF from 33 ± 35 episodes to nil for 25 ± 18 months. In addition, quinidine restored a normal electrocardiogram. Conclusions Multiple recurrences of VF occurred in 27% of patients with early repolarization abnormality and may be life threatening. Isoproterenol in acute cases and quinidine in chronic cases are effective AADs.
Objectives We evaluated the feasibility and safety of epicardial substrate elimination with endocardial radiofrequency (RF) delivery in patients with scar-related ventricular tachycardia (VT). ...Background Epicardial RF delivery is limited by fat or associated with bleeding, extra-cardiac damages, coronary vessels and phrenic nerve injury. Alternative ablation approaches might be desirable. Methods Forty-six patients (18 ischemic cardiomyopathy ICM, 13 nonischemic dilated cardiomyopathy NICM, 15 arrhythmogenic right ventricular cardiomyopathy ARVC) with sustained VT underwent combined endo- and epicardial mapping. All patients received endocardial ablation targeting local abnormal ventricular activities in the endocardium (Endo-LAVA) and epicardium (Epi-LAVA), followed by epicardial ablation if needed. Results From a total of 173 endocardial ablations targeting Epi-LAVA at the facing site, 48 (28%) applications (ICM: 20 of 71 28%, NICM: 3 of 39 8%, ARVC: 25 of 63 40%) successfully eliminated the Epi-LAVA. Presence of Endo-LAVA, the most delayed and low bipolar amplitude of Epi-LAVA, low unipolar amplitude in the facing endocardium, and Epi-LAVA within a wall thinning area at computed tomography scan were associated with successful ablation. Endocardial ablation could abolish all Epi-LAVA in 4 ICM and 2 ARVC patients, whereas all patients with NICM required epicardial ablation. Endocardial ablation was able to eliminate Epi-LAVA at least partially in 15 (83%) ICM, 2 (13%) NICM, and 11 (73%) ARVC patients, contributing to a potential reduction in epicardial RF applications. Pericardial bleeding occurred in 4 patients with epicardial ablation. Conclusions Elimination of Epi-LAVA with endocardial RF delivery is feasible and might be used first to reduce the risk of epicardial ablation.
Objectives The aim of this study was to identify families affected by early repolarization syndrome (ERS) and to determine the mode of transmission of the disease. Background Early repolarization ...(ER) has recently been linked to idiopathic ventricular fibrillation. Familial inheritance of the disease has been suggested but not demonstrated. Methods We screened relatives of 4 families affected by ERS. ER was defined as a distinct J-wave in at least 2 consecutive leads and a 1-mm amplitude above baseline. The Valsalva maneuver was performed in affected and unaffected family members to decrease heart rate and thus increase or reveal an ER pattern. Results Twenty-two sudden cardiac deaths occurred in the 4 families including 10 before 35 years of age. In the 4 families, the prevalence of ER was 56%, 34%, 61%, and 33% of, respectively, 30, 82, 29, and 30 screened relatives. In these families, transmission of an ER pattern is compatible with an autosomal dominant mode of inheritance. All probands were screened for genes identified in ERS, and no mutation was found. The Valsalva maneuver was performed in 80 relatives, resulting in increased J-wave amplitude for 17 of 20 affected patients and revealing an ER pattern in 17 relatives in whom 5 are obligate transmitters of an ER pattern. Conclusions ERS can be inherited through autosomal dominant transmission and should be considered a real inherited arrhythmia syndrome. Familial investigation can be facilitated by using the Valsalva maneuver to reveal the electrocardiographic pattern in family members. The prognosis value of this test remains to be assessed.
Prevalence and prognostic value of conduction disturbances in patients with the Brugada syndrome (BrS) remains poorly known. Electrocardiograms (ECGs) from 325 patients with BrS (47 ± 13 years, 258 ...men) with spontaneous (n = 143) or drug-induced (n = 182) type 1 ECG were retrospectively reviewed. Two hundred twenty-six patients (70%) were asymptomatic, 73 patients (22%) presented with unexplained syncope, and 26 patients (8%) presented with sudden death or implantable cardioverter-defibrillator appropriated therapies at diagnosis or during a mean follow-up of 48 ± 34 months. P-wave duration of ≥120 ms was present in 129 patients (40%), first degree atrioventricular block (AVB) in 113 (35%), right bundle branch block (BBB) in 90 (28%), and fascicular block in 52 (16%). Increased P-wave duration, first degree AVB, and right BBB were more often present in patients after drug challenge than in patients with spontaneous type 1 ST elevation. Left BBB was present in 3 patients. SCN5A mutation carriers had longer P-wave duration and longer PR and HV intervals. In multivariate analysis, first degree AVB was independently associated with sudden death or implantable cardioverter-defibrillator appropriated therapies (odds ratio 2.41, 95% confidence interval 1.01 to 5.73, p = 0.046) together with the presence of syncope and spontaneous type 1 ST elevation. In conclusion, conduction disturbances are frequent and sometimes diffuse in patients with BrS. First degree AVB is independently linked to outcome and may be proposed to be used for individual risk stratification.
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