Impact of cardiac resynchronization therapy optimization inside a heart failure programme: a real-world experience

Abstract

Aims: This study sought to describe and evaluate the impact of a routine in-hospital cardiac resynchronization therapy (CRT) programme, including comprehensive heart failure (HF) evaluation and systematic echo-guided CRT optimization.

Methods and results: CRT implanted patients were referred for optimization programme at 3 to 12 months from implantation. The program included clinical and biological status, standardized screening for potential cause of CRT non-response and systematic echo-guided atrioventricular and interventricular delays (AVd and VVd) optimization. Initial CRT-response and improvement at 6 months post-optimization were assessed with a clinical composite score (CCS). Major HF events were tracked during 1 year after optimization. A total of 227 patients were referred for CRT optimization and enrolled (71 ± 11 years old, 77% male, LVEF 30.6 ± 7.9%), of whom 111 (48.9%) were classified as initial non-responders. Left ventricular lead dislodgement was noted in 4 patients (1.8%), and loss or ≤90% biventricular capture in 22 (9.7%), mostly due to arrhythmias. Of the 196 patients (86%) who could undergo echo-guided CRT optimization, 71 (36.2%) required VVd modification and 50/144 (34.7%) AVd modification. At 6 months post-optimization, 34.3% of the initial non-responders were improved according to the CCS, but neither AVd nor VVd echo-guided modification was significantly associated with CCS-improvement. After one-year follow-up, initial non-responders maintained a higher rate of major HF events than initial responders, with no significant difference between AVd/VVd modified or not.

Conclusions: Our study supports the necessity of a close, comprehensive and multidisciplinary follow-up of CRT patients, without arguing for routine use of echo-guided CRT optimization.

Keywords: Atrioventricular delay; Cardiac resynchronization therapy; Echocardiography; Heart failure; Interventricular delay; Optimization.

Figure 1

Flow chart of the CRT optimization programme. CRT, cardiac resynchronization therapy; ECG, electrocardiogram; LVEF, left ventricle ejection fraction; AVd, atrioventricular delay; VVd, interventricular delay; LVOT VTI, left ventricular outflow tract velocity time integral.

Figure 2

Screening for potential causes of CRT non‐response. AVd, atrioventricular delay; VVd, interventricular delay; LV, left ventricular; HF, heart failure; BiV, biventricular; SVT, supraventricular tachycardia; PVC, premature ventricular contraction.

Figure 3

Distribution of AVd and VVd before and after optimization. (A) AS AVd before optimization. (B) AS AVd after optimization. (C) VVd before optimization. (D) VVd after optimization. AVd, atrioventricular delay; AS, atrial‐sensed; LV, left ventricular; RV, right ventricular; VVd, interventricular delay.

Figure 4

Examples of echo‐guided AVd and VVd optimization. (A, B) 78‐year‐old patient with non‐ishemic cardiomyopathy and complete AV block, implanted with CRT pacemaker. (A) Too long initial AS AVd (150 ms) with merged E and A waves. (B) Shortening the delay to 80 ms resulted in separation of (E) and (A). (C, D) 71‐year‐old patient with valvular cardiopathy and sinus node dysfunction, implanted with CRT defibrillator. (C) Too short initial AP AVd (120 ms) with truncated A wave. (D) After extension of AP AVd to 160 ms, mitral closure click was aligned with end of A wave. (E, F) 59‐year‐old patient with ischemic cardiomyopathy, complete LBBB and LVEF reduced to 25%, implanted with CRT defibrillator. Changing the VVd from 10 to 30 ms (LV first) resulted in an acute increase of LVOT VTI (12.3 cm to 16.8 cm, heart rate 65 b.p.m.). AVd, atrioventricular delay; AS, atrial‐sensed; AP, atrial‐paced; CRT, cardiac resynchronization therapy; LBBB, left bundle branch block; LV, left ventricular; LVEF, left ventricular ejection fraction; LVOT, left ventricular outflow tract; VTI, velocity time integral; VVd, interventricular delay.

Figure 5

Evolution of functional status according to the clinical composite score (CCS). CRT, cardiac resynchronization therapy.

Figure 6

Cumulative rate of major HF events (HF hospitalization, all‐cause death, heart transplantation, mechanical circulatory support) after optimization programme (1 year follow‐up). Kaplan–Maier curves for (A) initial CRT responders versus non‐responders; (B) initial CRT non‐responders AVd modified versus AVd non‐modified; (C) initial CRT non‐responders VVd modified versus VVd non‐modified. AVd, atrioventricular delay; CRT, cardiac resynchronization therapy; HF, heart failure; VVd, interventricular delay.