Outcome in patients undergoing upgrade to cardiac resynchronization therapy: predictors of outcome after upgrade to CRT.

The advantages of upgrade to cardiac resynchronisation therapy (CRT) have not been explored as carefully as the outcomes of de novo CRT implantations. Furthermore selection criteria for patients with the potential to benefit the most from this therapy are unknown. Therefore, we analyzed the long term outcome and its predictors in a real-world cohort receiving a CRT upgrade from previous pacemaker (PM) and defibrillator devices (ICD). We analyzed 86 patients (mean age 68 ± 9 years; 89% male) undergoing CRT upgrade procedures. Response to CRT as well as long term patient outcome was analyzed. NYHA class improved in majority of the patients during short term period (61%), and this trend remained constant during long term follow-up (54%). The observed all-cause mortality was 54% with mean survival of 49 ± 4 months. 11 patients underwent left ventricular assist device implantation or heart transplantation. In the multivariate analysis, only kidney function assessed by GFR (HR 0.97; 95% CI 0.95-0.99; p = 0.009) and LVEF (HR 0.92; 95% CI 0.87-0.97; p = 0.002) remain predictors for mortality. Patients who undergo an upgrade procedure to CRT demonstrate a significant response rate assessed by improvement in NYHA class, with initial baseline parameters such as LVEF and kidney function remaining significant predictors for mortality.

Ventriculoatrial conduction and related pacemaker-mediated arrhythmias in patients implanted for atrioventricular block: an old problem revisited.

INTRODUCTION: Ventriculoatrial (VA) conduction and related pacemaker-mediated tachyarrhythmias (PMT) have not been systematically investigated in a large cohort of patients implanted for symptomatic atrioventricular (AV) block. METHODS AND RESULTS: Two hundred fifty consecutive patients (71±14 years, 63% male) implanted for symptomatic second- or third-degree AV block were screened for retrograde VA conduction and related PMTs including endless loop tachycardia (ELT) and repetitive nonreentrant VA synchrony (RNRVAS). After a mean post-implantation period of 38±12 months, AV block was persistent in 137 (55%) and variable in 113 (45%) patients. Retrograde 1:1 conduction was present in 76 patients (30%) with a mean VA conduction time of 258±65 ms. The incidence of VA conduction varied considerably according to the presence and type of anterograde conduction block. Retrograde conduction was present in 24 of 137 patients (18%) with persistent AV block. Fifteen of the 76 patients (20%) with VA conduction had ≥1 documented PMT. The recorded arrhythmias were ELT in 11 and RNRVAS in 4 patients. VA conduction time was significantly longer in patients with than without PMT (297±64 vs. 249±62 ms, resp., P<0.01). None of the patients without VA conduction had documented PMTs. CONCLUSIONS: Retrograde VA conduction and related PMTs are not uncommon in patients implanted for symptomatic AV block. Testing for retrograde conduction should therefore be performed in all patients with AV block in order to optimize device programming and prevent PMTs.