SMART-AV and SMART-CRT: Improved cardiac outcomes with algorithm-adapted atrioventricular delay

Optimal sensed and paced atrioventricular delay can improve cardiac resynchronisation therapy response compared with recommended fixed atrioventricular delay in a subset of patients, according to a pooled analysis of clinical trial data.

SMART-AV (NCT00677014) and SMART-CRT (NCT03089281) were prospective, multicentre, double-blind, randomised trials of de novo cardiac resynchronisation therapy using an optimal sensed and paced atrioventricular delay. Both SMART-AV (not significant) and SMART-CRT (P=0.03) showed a trend in improving left ventricular end-systolic volume (LVESV) [1,2]. Prof. Christophe Leclercq (Hospital Pontchaillou of Rennes, France) presented a pooled analysis that included participants from both trials who met the inclusion criteria for SMART-CRT: indication for cardiac resynchronisation therapy and right ventricular-left ventricular duration ≥70 ms [3]. The pooled analysis included 226 participants with algorithm-adapted atrioventricular delay and 225 participants in the fixed atrioventricular delay (120 ms) group. Follow-up assessment was conducted after 6 months.

In the pooled analysis, cardiac resynchronisation therapy response (i.e. proportion with ≥15% reduction in LVESV) was significantly higher with the algorithm-adapted versus fixed atrioventricular delay strategy (74% vs 63%; P=0.014). Furthermore, the 6-month reduction in LVESV was -32% versus -23% (P=0.005), respectively, while left ventricular end-diastolic volume was -19% versus -14% (P=0.015). Left ventricular ejection fraction was improved by 53% and 40% in the 2 groups, respectively (P=0.012). Overall, 63% of participants had an algorithm-adapted atrioventricular delay outside of the fixed range of 100–120 ms recommended by most manufacturers of devices. Participants who had an algorithm-adapted atrioventricular delay outside of the fixed range had an OR 2.3 (95% CI 1.4–3.9; P=0.0001) of achieving a cardiac resynchronisation therapy response.

Algorithm-adapted atrioventricular delay “increases cardiac resynchronisation therapy response and reverse remodelling in patients with right ventricular-left ventricular duration intervals ≥70 ms,” concluded Prof. Leclercq based on this pooled analysis of the SMART-AV and SMART-CRT trials.

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   1. Ellenbogen KA, et al. Circulation. 2010;122(25):2660-8
   2. Gold MR, et al. Circ Arrhythm Electrophysiol. 2023;16(6):e011714.
   3. Leclercq C, et al. Effect of atrioventricular optimization on cardiac resynchronization response in patients with long interventricular electrical delays: A pooled analysis of the SMART-AV and SMART-CRT trials. Late-Breaking Science: devices. EHRA Congress 2024, 7–9 April, Berlin, Germany.

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Posted on 29 April, 202429 April, 2024