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Abstract Background Cardiac Implantable Electronic Devices (CIED) include pulse generators and leads. In some implanting centers, it is a common practice to combine devices with leads from different companies. Case series have reported episodic high‐impedance changes in Boston Scientific CIEDs with competitor leads. We investigated the incidence of high‐impedance abnormalities in matched versus mismatched Boston Scientific Accolade pacemakers. Methods A retrospective chart review identified all consecutive Boston Scientific Accolade pacemakers implanted between January 2017 and June 2019 at a Canadian tertiary care center. The primary outcome was the occurrence of transient, high‐impedance changes which resulted in a switch to unipolar pacing/sensing in the absence of any other identifiable lead issue. Fisher exact tests (two‐tailed, α = .05) were used to compare the incidence of outcomes in matched versus mismatched systems. Results 514 Boston Scientific Accolade pacemakers were associated with 882 individual leads. The primary outcome occurred with 21 leads (20 Medtronic and 1 Abbott), associated with occasional pacing inhibition, presyncope, and/or early surgical revision. Mismatched lead‐device pairs were significantly associated with CIED malfunction compared to matched lead‐device pairs (3.3% vs. 0%, p = .0019). The median time from implant to unipolar safety switch was 12.4 months. The median follow‐up time was 21.6 months. Conclusion Use of mismatched leads with a Boston Scientific Accolade device was associated with an increased risk of undesirable changes in sensing polarity with occasional inappropriate pacing inhibition. Awareness of this interaction can allow for the institution of appropriate programming remedies and may increase scrutiny of the use of mismatched CIED systems.

Abstract Background Evidence regarding the incremental benefit of cardiac resynchronization therapy (CRT) with a defibrillator (CRT‐D) versus without (CRT‐P) in elderly patients with heart failure is limited. We compared mortality and cardiac hospitalisation between CRT‐D and CRT‐P in the elderly. Methods A retrospective chart review identified all consecutive patients with age ≥75 with CRT implantation over the last 10 years at a Canadian tertiary care cardiac centre. Kaplan‐Meier survival analyses and cumulative incidence curves were used to compare mortality and time to first cardiac hospitalisation, respectively, with CRT‐D versus CRT‐P over a 3 year period. Analyses were also repeated with propensity score matching based on age, sex, primary versus secondary prevention, date of implant, and Charlson Comorbidity Index. Results One hundred and seventy CRT patients were identified. A total of 128 received CRT‐D while 42 received CRT‐P. Median age was 79 (IQR 77‐81), and the majority were male (83%). CRT‐P patients had a higher burden of comorbidities (Charlson score 7, IQR 6‐8) than CRT‐D patients (Charlson score 5, IQR 5‐7; P