High-degree atrioventricular block in patients with preexisting bundle branch block or bundle branch block occurring during transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has become the standard therapy for high-risk and non-operable patients with severe aortic stenosis. However, the procedure involves several adverse effects, such as rhythm and conduction disturbances. Patients with postprocedural left bundle branch block may have an increased mortality risk, whereas patients with preprocedural right bundle branch block display a higher rate of postinterventional bradyarrhythmias. OBJECTIVE: The purpose of this study was to investigate the occurrence of high-degree atrioventricular block (AVB) in patients with preexisting bundle branch block (BBB) or BBB occurring during TAVI. METHODS: In this prospective single-center study, 50 consecutive patients undergoing TAVI with the Medtronic CoreValve Revalving System were included. Of these patients, 17 with preexisting BBB or BBB occurring during TAVI received a primary prophylactic permanent DDD pacemaker, programmed to the SafeR-mode and featuring dual-channel event counters as well as stored intracardiac electrograms. Pacemaker readouts and intracardiac electrograms were analyzed for the occurrence of high-degree AVB. RESULTS: Ten of 17 patients (58.8%) with preexisting BBB or BBB occurring during TAVI developed episodes of high-degree AVB that were immediately terminated due to switch into DDD backup pacing. In 5 of the cases (29.4%), the first documented episode of high-degree AVB occurred after hospital discharge. Mean follow-up period was 578.1 ± 294.9 days. CONCLUSION: Development of high-degree AVB is a common complication in patients with preexisting BBB or BBB occurring during TAVI. Accordingly, intensified monitoring might be reasonable, especially in patients treated with the self-expandable Medtronic CoreValve Revalving System.

Transvenous, intracardial cardioversion for the treatment of postoperative atrial fibrillation.

Atrial fibrillation (AF) following cardiac surgery is an important factor contributing to postoperative morbidity. Transvenous, intracardial cardioversion (TIC) has been shown to be effective in the treatment of chronic AF, but is an invasive and cost-intensive procedure. However, TIC would definitely be a beneficial approach if recurrence of AF following TIC is low and pharmacological treatment could be avoided. Thus, we hypothesised that TIC would be superior to conventional treatment with amiodarone with respect to the conversion rate and recurrence of AF. We compared TIC and conventional amiodarone therapy in a prospective, randomised and controlled trial in patients who developed AF following cardiac surgery. Twenty-three patients developed AF out of a total of 76 patients who gave written informed consent. Eighteen of these AF patients could be randomised into two equally sized groups to receive either an ALERT pulmonary artery catheter and TIC, or a standard pulmonary artery catheter and treatment with amiodarone. Haemodynamic parameters were registered before intervention to exclude pulmonary hypertension or fluid overload. Rates of cardioversion were compared by a Likelyhood ratio test. Out of the nine ALERT patients, AF in five cases converted to sinus rhythm (SR) with a median of two shocks (6 J). After 24 hours however, only two patients remained in sinus rhythm. On the other hand, six of the nine patients treated with amiodarone were still in SR after 24 hours. Whereas no difference was detectable in the conversion rate, persistence of SR following TIC was low. Thus, TIC without antiarrhythmic treatment is not recommendable for the treatment of postoperative AF.