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Background Highly localized impedance (LI) measurements during atrial fibrillation (AF) ablation have recently emerged as a viable real‐time indicator of tissue characteristics and durability of the lesions created. We report the outcomes of acute and long‐term clinical evaluation of the new DirectSense algorithm in AF ablation. Methods Consecutive patients undergoing AF ablation were included in the CHARISMA registry. RF delivery was guided by the DirectSense algorithm, which records the magnitude and time‐course of the impedance drop. The ablation endpoint was pulmonary vein isolation (PVI), as assessed by the entrance and exit block. Results 3556 point‐by‐point first‐pass RF applications of >10 s duration were analyzed in 153 patients (mean age=59 ± 10 years, 70% men, 61% paroxysmal AF, 39% persistent AF). The mean baseline LI was 105 ± 15 Ω before ablation and 92 ± 12 Ω after ablation (p < .0001). Both absolute drops in LI and the time to LI drop (LI drop/τ) were greater at successful ablation sites (n = 3122, 88%) than at ineffective ablation sites (n = 434, 12%) (14 ± 8 Ω vs 6 ± 4 Ω, p < .0001 for LI; 0.73 [0.41–1.25] Ω/s vs. 0.35[0.22–0.59 Ω/s, p < .0001 for LI drop/τ). No major complications occurred during or after the procedures. All PVs had been successfully isolated. During a mean follow‐up of 366 ± 130 days, 18 patients (11.8%) suffered an AF/atrial tachycardia recurrence after the 90‐day blanking period. Conclusion The magnitude and time‐course of the LI drop during RF delivery were associated with effective lesion formation. This ablation strategy for PVI guided by LI technology proved safe and effective and resulted in a very low rate of AF recurrence over 1‐year follow‐up.

AimsTo evaluate clinical and arrhythmic outcomes in post-infarction cardiomyopathy patients implanted with a defibrillator (ICD) for primary prevention of sudden death.Methods and resultsThe SEARCH-MI registry is a European multi-centre, prospective, observational study enrolling patients after myocardial infarction, chronic left ventricular dysfunction and an ICD implanted for primary prevention of sudden death. Data on 556 patients with at least one recorded follow-up are presented. Survey to Evaluate Arrhythmia Rate in High-risk MI (SEARCH-MI) patients were sicker than those enrolled in MADIT-II with higher New York Heart Association class and left bundle branch block. Total mortality was 10.4%. Close to one-third (30%) of patients experienced episodes of sustained ventricular arrhythmia. One-quarter (23%) received at least one appropriate therapy and 10% inappropriate therapy. Gender (25% males vs. 5% females, P = 0.0009) and history of non-sustained ventricular tachycardia (24% with vs. 18% without P = 0.037) were predictive of appropriate ventricular therapy.ConclusionSEARCH-MI represents the current clinical management of post-MI patients with left ventricular dysfunction indicated to defibrillator implant for primary prevention. European routine clinical practice was influenced by landmark trials and guidelines which impacted on the implantation of cardiac resynchronization therapy in over 25% of such patients. Non-sustained ventricular tachycardia identifies subjects with a higher incidence of appropriate ICD therapy.

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The mechanisms of atrial fibrillation (AF) induction and maintenance, including those involved in paroxysmal atrial fibrillation, are not completely known; this limits our ablation strategies and prevents us from understanding what we are actually doing when performing pulmonary vein isolation. In this report, we focus on the commonly used ablation strategies for AF and question the importance of complete pulmonary vein isolation in achieving lasting success in the ablation of AF. We also discuss in detail the absence of durable pulmonary vein isolation in patients without arrhythmic recurrences after AF ablation and the possibility to cure paroxysmal AF without concomitant pulmonary vein isolation, provocatively questioning the dogma of pulmonary vein isolation as the cornerstone of AF ablation. Finally, a prospective personalized approach in the individual patient is advocated. K E Y W O R D Sablation, atrial fibrillation, high-density mapping system, pulmonary vein isolation, substrate 1 1056