Nkomo, Vuyisille T.

Introduction: Clinical predictive value of transient prolonged ventricular conduction and repolarization during right ventricular (RV) pacing have not been studied. Hypothesis: Ventricular conduction and repolarization prolongation during RV pacing predict risk of arrhythmic and mortality events. Methods: Electrophysiology studies in 501 patients with cardiomyopathy (CM) were reviewed. Duration changes of QRS and QT interval during pacing from the RV apex were measured. Subjects were followed up for a mean of 3.2 years for arrhythmic events and total mortality. Results: Participants had a mean age 65 yrs, 80% male, 74% funcional class II or III, and a mean EF of 33.1%. A paced QRS duration > 190 ms was associated with more severe CM and in multi-variable analysis it was associated with a 3.5 times higher risk of ventricular arrhythmias or appropriate defibrillator therapy (HR 3.5, 95% CI 2.3-5.4, p<0.01) and 2.6 times higher risk of total mortality or arrhythmic events (HR 2.6, 95% CI 2.3-3.4, p<0.01) compared to a paced QRS duration <190 ms, independent of baseline EF or baseline QRS duration, and after adjustment for electrophysiology study results, baseline functional class, type of cardiomyopathy and other relevant clinical factors. Similarly a QTc interval during RV pacing > 620 ms was associated with a 2.7 times higher risk of arrhythmic events compared to a QTc interval during RV pacing < 620 ms. Conclusions: Prolongation of ventricular conduction (QRS > 190 ms) and repolarization (QTc > 620 ms) observed during RV pacing in subjects with CM are associated with higher risk of arrhythmic events, defibrillator therapies and all-cause mortality.

ObjectivesThis study sought to assess the learning curve for TMVR for treatment of primary mitral regurgitation (MR).BackgroundData are lacking regarding the technical experience required to achieve optimal clinical outcomes with transcatheter mitral valve repair (TMVR) using the edge‐to‐edge MitraClip technique.MethodsWe examined the sequential experience of the first 75 patients (age 80 ± 9 years; 77% male) who underwent TMVR at our institution. A sequence number of each patient was assigned as a continuous variable and in tertiles for analysis.ResultsTMVR with MitraClip was successful in 97% with an average procedural time of 106 ± 39 minutes. The 30‐day rate of major adverse cardiovascular events was 7%. With increased case experience, there were decreases in procedural time, fluoroscopy time, length of hospital stay, and major adverse cardiovascular events. Procedural success, residual mitral regurgitation and NYHA functional classification at 30‐day follow‐up remained unchanged throughout the experience.ConclusionsThe learning curve for TMVR with MitraClip for treatment of primary MR is characterized by a sequential reduction in procedure time, fluoroscopy time, procedural complications, and hospital length of stay at a tertiary academic medical center. Thirty‐day procedural results are favorable and similar during the initial learning period.