Repolarization abnormalities in the inferior-lateral leads in Brugada syndrome (BS) have not been systematically investigated. 280 patients (age, 41+/-18 years; 168 males) with BS were screened for inferior-lateral repolarization abnormalities. The repolarization abnormalities were classified either as early repolarization pattern or coved > or = 2-mm Brugada pattern and as spontaneous or class I antiarrhythmic drug (AAD) induced. Thirty-two patients (11%) had inferior-lateral spontaneous early repolarization pattern. These patients were less likely to be asymptomatic at first presentation (13 of 32 versus 156 of 248 patients, P=0.02), and spontaneous type I ECG was more frequent among them (38% versus 21%, P=0.05). The spontaneous early repolarization pattern occurred more frequently among patients with BS than in 283 family members not having BS (11% versus 6%, P=0.03). Class I AAD administration provoked inferior-lateral coved Brugada pattern in 13 patients with BS. These patients had longer baseline PR intervals (206+/-48 versus 172+/-31 ms, P<0.001) and class I AAD-induced QRS interval prolongation (108 to 178 versus 102 ms to 131 ms, P<0.001). In 3 patients, the class I AAD-provoked coved Brugada pattern was only present in the inferior leads. Inferior-lateral early repolarization pattern occurs spontaneously relatively frequently in BS. These patients have a more severe phenotype. Class I AAD administration provokes inferior-lateral coved Brugada pattern in 4.6% of patients. We report for the first time 3 patients in whom the class I AAD-provoked coved Brugada pattern was only observed in the inferior leads.

Limited data exist on procedural and biophysical indicators of pulmonary vein (PV) isolation durability after the cryoballoon ablation of atrial fibrillation (AF). The aim of this study was to investigate the procedural and biophysical characteristics associated with late PV reconnection (PVR) and durable PV isolation (PVI) after cryoablation using the currently available second-generation cryoballoon. Data from 435 PVs targeted in 112 consecutive patients who underwent a repeat procedure 14 ± 3 months after an index cryoablation of AF were examined. Altogether, 111 PVs (25.5%) in 71 patients (63.4%) demonstrated PVR, whereas 324 PVs (74.5%) exhibited PVI. The number and duration of cryoballoon applications did not differ between PVR and PVI. However, the time to PV isolation (time to effect) was considerably shorter (39.1 ± 11.7 seconds vs 67.6 ± 19.7 seconds; P < .001), the balloon temperature at time to effect was significantly warmer (-32.1°C ± 7.8°C vs -39.4°C ± 5.8°C; P < .001), the balloon nadir temperature was slightly cooler (-48.7°C ± 4.6°C vs -47.8°C ± 2.9°C; P = .034), and the total thaw time (56.5 ± 25.4 seconds vs 34.8 ± 9.1 seconds; P < .001) and interval thaw times at 0°C (iTT0; 14.8 ± 10.9 seconds vs 7.1 ± 2.0 seconds; P < .001) and 15°C (54.2 ± 25.4 seconds vs 33.3 ± 9.1 seconds; P < .001) were notably longer with PVI than with PVR. However, only a time to effect of ≤60 seconds and an iTT0 of ≥10 seconds emerged as significant predictors of PV isolation durability. Consequently, in a multivariate model, presence of both criteria predicted <1% and their mere absence ~75% likelihood of PVR. A time to effect of ≤60 seconds and an iTT0 of ≥10 seconds significantly predict PV isolation durability after the cryoballoon ablation of AF. If both criteria are met, the likelihood of PV reconnection may be exceedingly low.

BACKGROUND: Pulsed field ablation (PFA) is increasingly used in clinical practice for the treatment of atrial fibrillation. While the susceptibility of erythrocytes to electroporation is well established, the effect of cardiac PFA technologies on hemolysis has remained underreported. The aim of this study was to investigate the incidence, severity, and clinical impact of PFA-induced hemolysis. METHODS: We included n=145 patients undergoing atrial fibrillation catheter ablation with a pentaspline PFA catheter (biphasic, bipolar pulses of 2 kV) and n=70 patients receiving radiofrequency ablation (40–90 W) at 4 high-volume European centers. The lesion set comprised pulmonary vein isolation for paroxysmal atrial fibrillation and pulmonary vein isolation±additional lesions for persistent atrial fibrillation. Hemolysis and renal function biomarkers were analyzed in blood samples at baseline, at the end of ablation, and 24 hours after the procedure. RESULTS: Baseline characteristics were well balanced between groups (overall mean 65.7±9.4 years; 69.3% men). The ablation procedures comprised a mean of 61.6±27.4 PFA deliveries and 26.3±15.0 minutes RF duration. Hemolysis was detected in 94.3% versus 6.8% of patients after PFA versus radiofrequency ablation ( P <0.001): PFA was associated with significantly lower haptoglobin levels (0.5±0.4 versus 1.0±0.4 g/L), while free plasma hemoglobin (592.8±330.6 versus 147.8±183.0 mg/L), bilirubin (21.3±11.3 versus 14.8±8.8 µmol/L), and LDH (lactate dehydrogenase, 352.7±115.7 versus 253.2±56.5 U/L) were significantly higher after PFA compared with radiofrequency ablation (all P <0.001). Hemolysis correlated with the number of PFA deliveries (r=0.62 [95% CI, 0.33–0.80]; P <0.001), with the highest severity occurring ≥54 PFA deliveries. After PFA, hemoglobinuria occurred in 36.4%, while creatinine increase was higher in patients with baseline glomerular filtration rate 50 mL/min (Δcrea, 27.0±103.1 versus −0.2±12.1 µmol/L; P =0.010). CONCLUSIONS: Intravascular hemolysis is a frequent finding after PFA and increases with the number of PFA deliveries. Until the clinical impact of PFA-associated hemolysis is fully elucidated, a careful titration of PFA deliveries during the ablation procedure is warranted.