Complications in pulmonary vein isolation in the Netherlands Heart Registration differ with sex and ablation technique.

AIMS: Pulmonary vein isolation (PVI) has become a cornerstone of the invasive treatment of atrial fibrillation. Severe complications are reported in 1-3% of patients. This study aims to compare complications and follow-up outcome of PVI in patients with atrial fibrillation. METHODS AND RESULTS: The data were extracted from the Netherlands Heart Registration. Procedural and follow-up outcomes in patients treated with conventional radiofrequency (C-RF), multielectrode phased RF (Ph-RF), or cryoballoon (CB) ablation from 2012 to 2017 were compared. Subgroup analysis was performed to identify variables associated with complications and repeat ablations. In total, 13 823 patients (69% male) were included. The reported complication incidence was 3.6%. Patients treated with C-RF developed more cardiac tamponades (C-RF 0.8% vs. Ph-RF 0.3% vs. CB 0.3%, P ≤ 0.001) and vascular complications (C-RF 1.7% vs. Ph-RF 1.2% vs. CB 1.3%, P ≤ 0.001). Ph-RF was associated with fewer bleeding complications (C-RF: 1.0% vs. Ph-RF: 0.4% vs. CB: 0.7%, P = 0.020). Phrenic nerve palsy mainly occurred in patients treated with CB (C-RF: 0.1% vs. Ph-RF: 0.2% vs. CB: 1.5%, P ≤ 0.001). In total, 18.4% of patients were referred for repeat ablation within 1 year. Female sex, age, and CHA2DS2-VASc were independent risk factors for cardiac tamponade and bleeding complications, with an adjusted OR for female patients of 2.97 (95% CI 1.98-4.45) and 2.02 (95% CI 1.03-4.00) respectively. CONCLUSION: The reported complication rate during PVI was low. Patients treated with C-RF ablation were more likely to develop cardiac tamponades and vascular complications. Female sex was associated with more cardiac tamponade and bleeding complications.

Dispersion of repolarization in cardiac resynchronization therapy.

BACKGROUND: Proarrhythmic effects of cardiac resynchronization therapy (CRT) as a result of increased transmural dispersion of repolarization (TDR) induced by left ventricular (LV) epicardial pacing in a subset of vulnerable patients have been reported. The possibility of identifying these patients by ECG repolarization indices has been suggested. OBJECTIVES: The purpose of this study was to test whether repolarization indices on the ECG can be used to measure dispersion of repolarization during pacing. METHODS: CRT devices of 28 heart failure patients were switched among biventricular, LV, and right ventricular (RV) pacing. ECG indices proposed to measure dispersion of repolarization were calculated. The effects of CRT on repolarization were simulated in ECGSIM, a mathematical model of electrocardiogram genesis. TDR was calculated as the difference in repolarization time between the epicardial and endocardial nodes of the heart model. PATIENTS: The interval from the apex to the end of the T wave was shorter during biventricular pacing (102 +/- 18 ms) and LV pacing (106 +/- 21 ms) than during RV pacing (117 +/- 22 ms, P < or =.005). T-wave amplitude and area were low during biventricular pacing (287 +/- 125 microV and 56 +/- 22 microV.s, respectively, P = .0006 vs RV pacing). T-wave complexity was high during biventricular pacing (0.42 +/- 0.26, P = .004 vs RV pacing). Simulations: Repolarization patterns were highly similar to the preceding depolarization patterns. The repolarization patterns of different pacing modes explained the observed magnitudes of the ECG repolarization indices. Average and local TDR were not different between pacing modes. CONCLUSION: In patients treated with CRT, ECG repolarization indices are related to pacing-induced activation sequences rather than transmural dispersion. TDR during biventricular and LV pacing is not larger than TDR during conventional RV endocardial pacing.

Validation of ECG indices of ventricular repolarization heterogeneity: a computer simulation study.

INTRODUCTION: Repolarization heterogeneity (RH) is functionally linked to dispersion in refractoriness and to arrhythmogenicity. In the current study, we validate several proposed electrocardiogram (ECG) indices for RH: T-wave amplitude, -area, -complexity, and -symmetry ratio, QT dispersion, and the Tapex-end interval (the latter being an index of transmural dispersion of the repolarization (TDR)). METHODS AND RESULTS: We used ECGSIM, a mathematical simulation model of ECG genesis in a human thorax, and varied global RH by increasing the standard deviation (SD) of the repolarization instants from 20 (default) to 70 msec in steps of 10 msec. T-wave amplitude, -area, -symmetry, and Tapex-end depended linearly on SD. T-wave amplitude increased from 275 +/- 173 to 881 +/- 456 muV, T-wave area from 34 x 10(3)+/- 21 x 10(3) to 141 x 10(3)+/- 58 x 10(3)muV msec, T-wave symmetry decreased from 1.55 +/- 0.11 to 1.06 +/- 0.23, and Tapex-end increased from 84 +/- 17 to 171 +/- 52 msec. T-wave complexity increased initially but saturated at SD = 50 msec. QT dispersion increased modestly until SD = 40 msec and more rapidly for higher values of SD. TDR increased linearly with SD. Tapex-end increased linearly with TDR, but overestimated it. CONCLUSION: T-wave complexity did not discriminate between differences in larger RH values. QT dispersion had low sensitivity in the transitional zone between normal and abnormal RH. In conclusion, T-wave amplitude, -area, -symmetry, and, with some limitations, Tapex-end and T-wave complexity reliably reflect changes in RH.

Reduction of QRS duration after pulmonary valve replacement in adult Fallot patients is related to reduction of right ventricular volume.

AIMS: Late after total correction, Fallot patients with a long QRS duration are prone to serious arrhythmias and sudden cardiac death. Pulmonary regurgitation is a common cause of right ventricular (RV) failure and QRS lengthening. We studied the effects of pulmonary valve replacement (PVR) on QRS duration and RV volume. METHODS AND RESULTS: Twenty-six consecutive Fallot patients were evaluated both pre-operatively and 6-12 months post-operatively by cardiac magnetic resonance (CMR). In this study, we present the computer-assisted analysis of the standard 12-lead electrocardiograms closest in time to the CMR studies. For the whole group, QRS duration shortened by 6+/-8 ms, from 151+/-30 to 144+/-29 ms (P=0.002). QRS duration decreased in 18 of 26 patients by 10+/-6 ms, from 152+/-32 to 142+/-31 ms. QRS duration remained constant or increased slightly in eight of 26 patients by 3+/-3 ms, from 148+/-27 to 151+/-25 ms. CMR showed a decrease in RV end-diastolic volume from 305+/-87 to 210+/-62 mL (P=0.000004). QRS duration changes correlated with RV end-diastolic volume changes (r=0.54, P=0.01). CONCLUSION: Our study shows that PVR reduces QRS duration. The amount of QRS reduction is related to the success of the operation, as expressed by the reduction in RV end-diastolic volume.

Hypertensive stress increases dispersion of repolarization.

Several electrocardiographic indices for repolarization heterogeneity have been proposed previously. The behavior of these indices under two different stressors at the same heart rate (i.e., normotensive gravitational stress, and hypertensive isometric stress) was studied. ECG and blood pressure were recorded in 56 healthy men during rest (sitting with horizontal legs), hypertensive stress (performing handgrip), and normotensive stress (sitting with lowered legs). During both stressors, heart rates differed <10% in 41 subjects, who constituted the final study group. Heart rate increased from 63 +/- 9 beats/min at rest to 71 +/- 11 beats/min during normotensive, and to 71 +/- 10 beats/min during hypertensive stress (P < 0.001). Systolic blood pressure was 122 +/- 15 mmHg at rest and 121 +/- 15 mmHg during normotensive stress, and increased to 151 +/- 17 mmHg during hypertensive stress (P < 0.001). The QT interval was larger during hypertensive (405 +/- 27) than during normotensive stress (389 +/- 26, P < 0.001). QT dispersion did not differ significantly between the two stressors. The mean interval between the apex and the end of the T wave (Tapex-Tend) of the mid-precordial leads was larger during hypertensive (121 +/- 17 ms) than during normotensive stress (116 +/- 15 ms, P < 0.001). The singular value decomposition T wave index was larger during hypertensive (0.144 +/- 0.071) than during normotensive stress (0.089 +/- 0.053, P < 0.001). Most indices of repolarization heterogeneity were larger during hypertensive stress than during normotensive stress. Hypertensive stressors are associated with arrhythmogeneity in vulnerable hearts. This may in part be explained by the induction of repolarization heterogeneity by hypertensive stress.