Clinical Impact of Preexisting Right Bundle Branch Block after Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis.

INTRODUCTION: Transcatheter aortic valve replacement (TAVR) is now the treatment of choice for patients with severe aortic stenosis regardless of their surgical risk. Right bundle branch block (RBBB) can be a predictor for development of significant atrioventricular (AV) block after TAVR, requiring permanent pacemaker implantation (PPI). However, data related to the risk of PPI requirement with preexisting RBBB is scarce. Hence, this systematic review and meta-analysis aims to assess clinical outcomes of patients undergoing TAVR with RBBB on preexisting electrocardiogram. METHODS: We performed a systematic literature review to identify randomized and nonrandomized clinical studies that reported any clinical impact of patients undergoing TAVR with preexisting RBBB. A total of eight databases including PubMed (Medline), Embase, Cochrane Library, ACP Journal Club, Scopus, DARE, and Ovid containing articles from January 2000 to May 2020 were analyzed. RESULTS: We identified and screened 224 potential eligible publications through the databases and found 14 relevant clinical trials for a total of 15,319 participants. There was an increased 30-day pacemaker implantation rate of 38.1% in the RBBB group compared to 11.4% in the no RBBB group with a risk ratio of 3.56 (RR 3.56 (95% CI 3.21-3.93, p < 0.01)). There was an increased 30-day all-cause mortality in the RBBB group of 9.5% compared with 6.3% in the no RBBB group with an odds ratio of 1.60 (OR 1.60 (95% CI 1.14-2.25, p < 0.01)). CONCLUSION: This study indicates that patients with preexisting RBBB have higher incidence of PPI and all-cause mortality after TAVR compared with patients without RBBB. Further trials are needed to compare the clinical outcomes based on TAVR valve types and assess the benefit of PPI in patients with new-onset RBBB after TAVR.

Wearable cardioverter defibrillator in stress cardiomyopathy and cardiac arrest.

A 57-year-old woman presented with nausea, vomiting and diarrhoea. She had severe hypokalaemia and hypomagnesemia with marked QTc (680 ms) prolongation after suspected viral diarrhoea. She then developed progressive dyspnoea with congestion. An echocardiogram was obtained and showed severe hypokinesis with apical ballooning and hyperdynamic cardiac base, suggestive of stress cardiomyopathy. A repeat ECG showed further prolongation of the QTc (883 ms) and she rapidly developed polymorphic ventricular tachycardia. She underwent cardiac arrest and was successfully resuscitated. A coronary angiogram confirmed the diagnosis of stress cardiomyopathy. We had therapeutic dilemma at discharge to implant a permanent automated implantable cardiac defibrillator in view of the high risk for recurrent ventricular tachycardia, or follow-up for resolution of both reversible causes of the prolonged QTc (stress cardiomyopathy and electrolytes abnormalities). We suggested an alternate treatment for sudden death prevention in high risk patients who have reversible cause for QT interval prolongation.

Pacemakers and defibrillators: recent and ongoing studies that impact the elderly.

Since the first implantation of a cardiac pacemaker in the second half of the 20th century, there have been evolutionary and revolutionary advances in the technology developed for patients with heart rhythm disturbances. These advances, however, have instead failed to demonstrate that mimicry of physiology by a pacing system would deliver a longer and better life to its recipient. Indeed, we are just now in the process of developing a new paradigm in pacing that may finally deliver physiology to the hyperbolically named "physiologic pacing." This article will discuss the reasons for the discrepancy between the earlier studies and the more recent ones, as well as a review of implantable cardioverter-defibrillator trials, keeping in focus the special needs of aged heart rhythm device recipients.