Echocardiographic Dyssynchrony and Health Status Outcomes From Cardiac Resynchronization Therapy: Insights From the PROSPECT Trial

Abstract

This study sought to assess the prognostic utility of echocardiographic dyssynchrony for health status improvement after cardiac resynchronization therapy (CRT). Echocardiographic measures of dyssynchrony have been proposed for patient selection for CRT, but prospective validation studies are lacking. A prospective cohort of 324 patients from 53 centers with moderate to severe heart failure, left ventricular dysfunction, QRS > or =130 ms, and available echocardiographic and health status information were identified from the PROSPECT (Predictors of Response to Cardiac Re-Synchronization Therapy) trial, which evaluated the prognostic utility of dyssynchrony measures in CRT recipients. The association of 12 echocardiographic dyssynchrony parameters with 6-month improvement in health status, as measured by the Kansas City Cardiomyopathy Questionnaire (KCCQ), was assessed both as a continuous variable and by responder status (DeltaKCCQ > or =+10 points reflecting moderate to large improvement). Of 12 pre-defined dyssynchrony parameters, only 3 were consistently reported: interventricular mechanical delay (IVMD), left ventricular filling time relative to the cardiac cycle (LVFT), and left ventricular pre-ejection interval. After multivariable adjustment, IVMD (+5.18, 95% confidence interval [CI]: +0.76 to +9.60; p = 0.02) and LVFT (+5.19, 95% CI: +0.45 to +0.94; p = 0.03) were independently associated with 6-month improvements in KCCQ. Patients with 6-month improvements in KCCQ had lower subsequent mortality (adjusted hazard ratio [HR] for each 5-point improvement: 0.83; 95% CI: 0.72 to 0.93; p = 0.03). Additionally, IVMD was associated with CRT responder status (for DeltaKCCQ > or =+10 points: odds ratio [OR]: 1.85; 95% CI: 1.12 to 3.05; p = 0.03), whereas LVFT was not (OR: 1.63; 95% CI: 0.85 to 3.11; p = 0.14). Patients classified as health status responders had a 76% lower subsequent risk of all-cause mortality (adjusted HR: 0.24; 95% CI: 0.07 to 0.84; p = 0.03). The presence of pre-implantation IVMD and LVFT was associated with 6-month health status improvement, and IVMD was associated with a significant CRT response. These echocardiographic factors may help clinicians counsel patients regarding their likelihood of symptomatic improvement with CRT. ( Predictors of Response to Cardiac Re-Synchronization Therapy; NCT00253357).