Challenges and Outcomes of Posterior Wall Isolation for Ablation of Atrial Fibrillation.

BACKGROUND: The left atrial posterior wall (PW) often contains sites required for maintenance of atrial fibrillation (AF). Electrical isolation of the PW is an important feature of all open surgeries for AF. This study assessed the ability of current ablation techniques to achieve PW isolation (PWI) and its effect on recurrent AF. METHODS AND RESULTS: Fifty-seven consecutive patients with persistent or high-burden paroxysmal AF underwent catheter ablation, which was performed using an endocardial-only (30) or a hybrid endocardial-epicardial procedure (27). The catheter ablation lesion set included pulmonary vein antral isolation and a box lesion on the PW (roof and posterior lines). Success in creating the box lesion was assessed as electrical silence of the PW (voltage <0.1 mV) and exit block in the PW with electrical capture. Cox proportional hazards models were used for analysis of AF recurrence. PWI was achieved in 21 patients (36.8%), more often in patients undergoing hybrid ablation than endocardial ablation alone (51.9% versus 23.3%, P=0.05). Twelve patients underwent redo ablation. Five of 12 had a successful procedural PWI, but all had PW reconnection at the redo procedure. Over a median follow-up of 302 days, 56.1% of the patients were free of atrial arrhythmias. No parameter including procedural PWI was a statistically significant predictor of recurrent atrial arrhythmias. CONCLUSIONS: PWI during catheter ablation for AF is difficult to achieve, especially with endocardial ablation alone. Procedural achievement of PWI in this group of patients was not associated with a reduction in recurrent atrial arrhythmias, but reconnection of the PW was common.

Ablation of atrial tachycardia and atrial flutter in heart failure.

Atrial tachycardia and atrial flutter are common tachyarrhythmias in the heart failure population. They commonly lead to, exacerbate, and increase the morbidity and mortality associated with heart failure and, thereby, warrant urgent and early definitive therapy in the form of catheter ablation. Catheter ablation requires careful patient stabilization and extensive preprocedural planning, particularly with regards to anesthesia, strategy, catheter choice, mapping system, and fluid balance, to increase efficacy and limit adverse effects. Heart failure may limit the success of catheter ablation with higher reported recurrence rates, and in selected patients, a hybrid epicardial-endocardial ablation can be considered.

High Prevalence of Hypertension and Other Cardiometabolic Risk Factors in US- and Caribbean-Born Blacks with Chest Pain Syndromes.

BACKGROUND: Caribbean-born blacks (CBB) have been reported to have lower coronary artery disease mortality rates than US-born blacks (UBB). We assessed whether CBB have a lower prevalence of cardiometabolic risk factors compared to UBB. METHODS: Non-Hispanic blacks (n = 275) hospitalized for chest pain who were prospectively enrolled in our Cardiovascular Outcomes Research Group (CORG) study provided clinical and demographic data. RESULTS: The study cohort comprised 45% (n = 125) UBB with a mean age of 61 ± 16 years and 55% (n = 150) CBB with a mean age of 63 ± 11 years. Myocardial infarction was diagnosed in 33% of UBB and 36% of CBB. CBB had a lower rate of previous myocardial infarction (14 vs. 24%; p = 0.04). They also smoked less (16 vs. 35%; p = 0.001) and were less likely to have first-degree relatives with coronary artery disease (24 vs. 41%; p = 0.018). However, they had a similarly high prevalence of hypertension (99 vs. 98%; p = 0.99), diabetes (58 vs. 48%; p = 0.11), dyslipidemia (53 vs. 42%; p = 0.08), and obesity (34 vs. 40%; p = 0.29) as UBB. CONCLUSION: A very high prevalence of hypertension exists in non-Hispanic blacks hospitalized for chest pain. CBB and UBB have a similar prevalence of cardiometabolic profile in our study population. Besides smoking, other factors contributing to lower CHD mortality reported for CBB need to be further explored.