Exercise test is essential in LV-only fusion CRT pacing without right ventricle lead

• Published in: Clinical interventions in aging Vol. 14; pp. 969 - 975
• Main Authors: Vacarescu, Cristina, Cozma, Dragos, Petrescu, Lucian, Dragan, Simona, Mornos, Cristian, Crisan, Simina, Feier, Horea, Lazar, Mihai-Andrei, Cozlac, Ramona Alina, Luca, Constantin Tudor
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01-06-2019; Dove; Dove Medical Press
• Subjects: Analysis; cardiac resynchronization therapy; Cardiac Resynchronization Therapy - methods; Cardiovascular Diseases - diagnosis; Cardiovascular Diseases - physiopathology; Cardiovascular Diseases - therapy; constant fusion pacing; Echocardiography; Exercise - physiology; exercise test; Exercise Test - methods; Exercise tests; Female; Follow-Up Studies; Health aspects; Heart Atria - physiopathology; Heart rate; Heart Ventricles - physiopathology; Humans; Ivabradine; LV only pacing; Male; Middle Aged; Original Research; Physiological aspects; Prospective Studies; Public relations; Treatment Outcome; constant fusion pacing; cardiac resynchronization therapy; exercise test; LV-only pacing
• ISSN: 1178-1998; 1176-9092; 1178-1998
• DOI: 10.2147/CIA.S206251

Left ventricle (LV)-only pacing is non-inferior to biventricular pacing but permanent fusion pacing is needed to ensure cardiac resynchronization therapy (CRT) responsiveness. The role of systematic exercise testing (ET) in these patients has not been established. This study was designed to assess clinical and therapeutic implications (device programming/drugs) of systematic ET in patients requiring fusion-pacing CRT without an right ventricle (RV) lead.
Consecutive patients with a right atrium/LV-only dual-chamber (DDD) pacing system were included. Prospective data were obtained: device interrogation, ET, and echocardiography at every 6-month follow-up visit. CRT assessment during ET included maximal heart rate, beat-to-beat echocardiography analysis of LV fusion pacing, LV loss of capture, and improvement in exercise capacity. If LV loss of capture or unsatisfactory LV fusion pacing occurred, reprogramming was individualized for each patient and ET redone.
A total of 55 patients (29 male) aged 62±11 years were included. During follow-up (39±18 months), a total of 235 ETs were performed, with mean exercise load 6.4±1.3 metabolic equivalents of task (118±35 W, maximal heart rate 119±17 beats/min). Twenty patients (36%) had inadequate pacing or loss of LV capture during ET, due to exceeding the maximum tracking rate (11%), chronotropic incompetence (7%), and LV pacing outside the fusion-pacing band (18%), caused by physiological shortening of the PR interval or exagerated LV preexcitation during maximum exercise. Post-ET CRT-device optimization included reprogramming of rate-adaptive atrioventricular interval (total decrease 23±8 ms), individualized programming of maximum tracking rate, or rate-response function. Drug optimization was performed in 32% of patients, and ET redone in 36%.
In one of three ETs, an intervention in device and medication optimization was done to ensure a better outcome. Routine ET should be a standard approach to maximize fusion-pacing CRT response during follow-up.