Abstract: The follow-up of 1440 consecutive post-MI patients (68.9+/-10.9 years) with an LVEF</=40% was analyzed in 19 Italian hospitals to evaluate how many patients with clinical nonsustained VT and inducible sustained VT or VF underwent post-discharge risk assessment (RA). During 38 (range, 4-76) months follow-up, 611 patients (42.4%) qualified for and 294 (20.4%) effectively underwent RA combining LVEF assessment and Holter monitoring, 29 (2.0%) subsequently underwent programmed electrical stimulation and 19 (1.3%) received an ICD.

Abstract: BACKGROUND: The optimal programming of a pacemaker (PM) voltage output considers both efficiency (prolonging battery cell longevity) and patient safety (adequate safety margin). Currently, automatic capture (AC) algorithms are designed to ensure safe automatic stimulation threshold determination and pacing with a safety margin. METHODS: The aims of this prospective observational study were (1) to evaluate, over a short-term follow-up, the extent of backup pacing in patients implanted with an AC-featured PM produced by Boston Scientific (Insignia) and a wide range of ventricular leads; (2) to identify patient- or lead-specific predictors of ventricular threshold increase or missed detection of the ventricular pacing threshold; and (3) to analyze day-to-day fluctuations in the ventricular pacing threshold and the relationship between their magnitude, the characteristics of patients, and the system implanted. RESULTS: Five hundred and seventy-nine patients implanted with 89 different leads were followed up for a median of 2.1 months. Five hundred and thirty-six patients (92.5%) never experienced failure of automatic threshold testing; 571 (98.6%) did not experience permanent failure requiring continuous backup pacing at high energy. On multivariate analysis, none of the patient or lead characteristics predicted the occurrence of high-energy backup pacing during the study period. Day-to-day threshold fluctuations were associated only with higher thresholds (>1 V). CONCLUSION: AC algorithm reliably measures ventricular pacing thresholds in most patients: in only 1.4% of patients the system is permanently unable to detect the ventricular threshold. Backup pacing is not dependent on lead or patient characteristics, including lead polarization, polarity, and maturation.

Abstract: BACKGROUND: In patients with atrial fibrillation (AF) undergoing radiofrequency (RF) electrical disconnection of multiple pulmonary veins (PVs), the incidence of late conduction recurrences has not been systematically determined. METHODS AND RESULTS: Using a prospectively designed, multistep approach, we aimed at assessing the correlation between acute achievement and chronic maintenance of electrical conduction block across RF lesions disconnecting the distal tract of the PV in 43 patients (52.3+/-8.2 years) with AF. Forty-one left superior (LS), 42 right superior (RS), 25 left inferior (LI), and 9 right inferior (RI) PVs were targeted during 108 EP procedures (2.6+/-0.5 per patient). Seventeen patients underwent 2 procedures, 23 patients underwent 3 procedures, and 3 patients underwent 4 procedures. During the first attempt, electrical disconnection was achieved in 112 PVs (95.7%). During a next procedure (time interval, 4.6+/-1.9 months), conduction recurrence was observed in 32 of 39 LSPVs (82.1%), 29 of 40 RSPVs (72.5%), 20 of 24 LIPVs (83.3%), and 7 of 9 RIPV (77.8%). After reablation at gap sites, a later procedure (time interval, 5.1+/-2.4 months) revealed a second recurrence in 13 of 22 LSPVs (59.1%) and 14 of 19 RSPVs (73.7%). CONCLUSIONS: Conduction recurrence across disconnecting RF lesions can be observed in approximately 80% of cases 4 months after ablation. After reablation, similar recurrence rates are observed 5 months later. This high rate of late conduction recurrence may contribute significantly to AF recurrence in patients undergoing catheter ablation aiming at disconnection of multiple PVs.

Abstract: Idiopathic dilated cardiomyopathy (DCM) accounts for about 10,000 deaths per year in western countries. Of these deaths, 8% to 51% occur suddenly, with more than half of the events due to a ventricular arrhythmia. Improvement in diagnostic techniques and therapeutic strategies, together with changes in secular trends, have likely contributed to the reported trend toward improved survival in recent years. Identification of DCM patients at higher risk of sudden death is difficult. Poor left ventricular function is the strongest predictor of all-cause death, whereas a history of sustained unstable ventricular arrhythmia or cardiac arrest identifies patients at high risk of sudden death. Recent data suggest that a history of syncope, regardless of inducibility at programmed electrical stimulation, may be a risk factor of sudden death. Despite the absence of controlled studies, use of implantable cardioverter defibrillator therapy for primary prevention can be considered in patients with unexplained syncope as well as subgroups of DCM patients awaiting transplantation. In patients who survive a cardiac arrest or an unstable ventricular tachycardia, use of implantable cardioverter defibrillator therapy is associated with improved survival during follow-up and should be considered as a first-line therapy.