Defining the blanking period, using continuous ECG monitoring, after cryoballoon pulmonary vein isolation.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. A blanking period (BP) of 3 months is used in clinical trials and practice. However, the optimal BP duration after PVI remains undefined. OBJECTIVE: The aim of this study was to objectively define, using continuous monitoring by an implantable loop recorder, the optimal BP duration after cryoballoon PVI. METHODS: We enrolled consecutive patients who had cryoballoon PVI and an implantable loop recorder. We determined the time of the last confirmed episode of AF within the blanking period. This was then correlated with AF recurrence in the first year after ablation. RESULTS: There were 210 patients (66 ± 9 years; 138 [66%] male; 116 [55%] paroxysmal AF; CHA2DS2-VASc score, 2.5 ± 1.6). We defined 4 distinct groups based on the last AF episode within the BP: no AF days 0-90 (n = 96 [46%]) and last AF 0-30 days (n = 46 [22%]), 31-60 days (n = 18 [9%]), and 61-90 days (n = 50 [24%]). After the 3-month BP, 101 (48%) patients had AF recurrence at 160 ± 86 days. Compared with patients with no AF in the BP, those with recurrent AF and AF burden >0% 30 days after ablation had a significantly greater AF recurrence during long-term follow-up (P = .001). CONCLUSION: Our data show that the approximately one-third of patients in whom AF occurs and who have a burden of >0% after the first month that follows PVI are at significantly higher risk of long-term recurrent AF. We therefore suggest that the blanking period be limited to a month after cryoballoon PVI.

Incidence and Predictors of Very Late Recurrence of Atrial Fibrillation Following Cryoballoon Pulmonary Vein Isolation.

BACKGROUND: A very late recurrence (VLR) of atrial fibrillation (AF) is considered present when the first recurrence of AF occurs ≥12 months following ablation. Prior studies characterizing VLR have not used an implantable loop recorder for ECG monitoring. Thus, it is unknown whether VLR truly occurs or whether these patients have simply had unrecognized AF. Our objective was to assess the incidence and predictors of VLR in patients who underwent cryoballoon pulmonary vein isolation alone, had an implantable loop recorder, and were confirmed AF free for at least 1 year. METHODS: We enrolled consecutive patients with paroxysmal or persistent AF who underwent cryoballoon pulmonary vein isolation and had an implantable loop recorder implanted <3 months post-ablation. Patients free of AF 1 year post-ablation were followed prospectively for recurrent AF. All AF episodes were adjudicated. RESULTS: We included 188 patients (66±10 years; 116 [62%] men; 102 [54%] paroxysmal AF; CHA2DS2-VASc, 2.6±1.7). After 1 year post-pulmonary vein isolation, 93 (49%) patients remained AF free. During subsequent follow-up, 30 (32%) patients had VLR of AF. The only independent risk factor for VLR was an elevated CHA2DS2-VASc score (hazard ratio, 1.317 [95% CI, 1.033-1.6979]; P=0.026). Patients with CHA2DS2-VASc score ≥4 represented a quarter of the population and were at the highest risk. CONCLUSIONS: Our data using implantable loop recorders for continuous ECG monitoring post-AF ablation show that VLR occurs in a third of patients after an apparently successful cryoballoon pulmonary vein isolation procedure. Additional strategies are needed to ensure long-term freedom from AF recurrences in these high-risk patients.

Incidence, duration, pattern, and burden of de novo atrial arrhythmias detected by continuous ECG monitoring using an implantable loop recorder following ablation of the cavotricuspid isthmus.

Background: Following cavotricuspid isthmus (CTI) ablation, many patients with atrial flutter (AFL) are diagnosed with atrial fibrillation (AF). The incidence, duration, pattern, and burden of AF remain undefined. These may have implications for the management of these patients. Objective: To classify the incidence, duration, pattern, and burden of AF/AFL using an implantable loop recorder (ILR) after CTI ablation. Methods: We enrolled consecutive patients with CTI-dependent AFL, no known history of AF, and CHA2DS2-VASc ≥ 2. An ILR was implanted before or within 90 days of ablation. The time to first AF/AFL, pattern, duration, and burden of longest AF/AFL were determined. Five distinct AF/AFL cohorts were identified: no AF/AFL and those with recurrences of isolated, clustered, frequent, or persistent AF/AFL. Results: Fifty-two patients (81% male; 73 ± 9 years; CHA2DS2-VASc 3.7 ± 1.2) were followed for 784 (interquartile range [IQR] 263, 1150) days. AF/AFL occurred in 44 (85%) patients at 64 (IQR 8, 189) days post-CTI ablation and was paroxysmal in 31 (70%) patients (burden 0.6% [IQR 0.1, 4.8]). AF/AFL was isolated (n = 5, 11%), clustered (n =7, 16%), frequent (n =19, 43%), and persistent (n =13, 30%). The longest AF episode was <24 hours in 27 (61%) patients. Conclusion: Following CTI ablation in AFL patients, although AF/AFL occurs in most patients, the burden is low and episodes were <24 hours in the majority of patients. Additional studies are needed to determine whether long-term electrocardiographic monitoring can help guide management of patients undergoing CTI ablation.

Brugada Syndrome Unmasked by Use of Testosterone in a Transgender Male: Gender Trumps Sex as a Risk Factor.

We describe a genetic female living as a transgender male through the use of exogenous testosterone supplementation. He developed Brugada pattern (that was unrecognized) and subsequently had an out-of-hospital cardiac arrest. Sustained ventricular arrhythmias were suppressed through treatment with quinidine; however, this medication could only be administered at very low doses due to the development of angioedema at higher doses. Subsequently, the patient required endocardial ablation for elimination of highly symptomatic, repetitive monomorphic ventricular ectopy. This case highlights the presentation of a unique patient in whom a channelopathy was unmasked by the patient's lifestyle, suggesting that gender trumps sex when it comes to arrhythmia risk in patients at risk for Brugada syndrome.

Dexmedetomidine sedation leading to refractory cardiogenic shock.

Dexmedetomidine is frequently used for deep sedation during electrophysiology procedures. We report a case where, presumably, the use of dexmedetomidine resulted in a patient's death. The patient developed unexplained and refractory cardiogenic shock and could not be resuscitated. Autopsy failed to demonstrate any abnormality or cause of death. We postulate that, in certain susceptible individuals, dexmedetomidine may lead to terminal complications. We therefore urge caution about using dexmedetomidine in the electrophysiology laboratory.

Long-term outcome following successful pulmonary vein isolation: pattern and prediction of very late recurrence.

BACKGROUND: Despite encouraging results of pulmonary vein isolation (PVI) ablation for atrial fibrillation (AF), it is unclear whether there is genuine cure or there is an important attrition rate. We sought to determine the long-term outcome of the initial responders who experienced a prolonged AF-free complete response. METHODS: From a series of 350 consecutive patients who underwent PVI for AF, 264 patients (75%) (males 71%, age 57 +/- 12 years, paroxysmal AF 87%) who demonstrated >or=1 year AF-free follow-up on no antiarrhythmic drugs were followed for 1-5 years. RESULTS: During 28 +/- 12 months follow-up, 23 of 264 (8.7%) patients had recurrence of AF. The actuarial recurrence at 2 years postablation was 5.8% and increased to 25.5% at 5 years. Compared with long-term responders, more patients with late recurrence had hypertension (HR = 2.18, P = 0.009) and hyperlipidemia (HR = 4.01, P = 0.0005). Among 18 patients with recurrent AF necessitating repeat PVI, 15 (83%) required re-isolation of > 1 PV and 28 of 45 (58%) PVs showed reconnection. All PVs were re-isolated and five (28%) patients had additional linear ablation. All 15 patients became AF-free again. CONCLUSIONS: Although most patients following PVI remain AF-free, some patients develop "late" recurrence of AF. The "late" recurrence patients are more likely to have hypertension and hyperlipidemia. Most late recurrences are associated with PV reconnections. Our observations emphasize the importance of continued long-term vigilance for AF recurrence, and also raise concerns regarding the need for long-term anticoagulation therapy.