Predictors of positive response to cardiac resynchronization therapy.

BACKGROUND: Approximately 30% of patients treated with cardiac resynchronization therapy (CRT) do not achieve favourable response. The purpose of the present study was to identify echocardiographic and clinical predictors of a positive response to CRT.

METHODS: The study included 82 consecutive heart failure (HF) patients in New York Heart Association (NYHA) functional class III or IV with left bundle branch block (LBBB), QRS duration ≥ 120 ms and left ventricular ejection fraction (LVEF) ≤ 35%. Statistical analysis was performed using IBM SPSS statistical software (SPSS v.21.0 for Mac OS X). A p value < 0.05 was considered statistically significant.

RESULTS: Echocardiographic response was established in 81.6% and clinical response was achieved in 82.9% of patients. Significant univariate predictors of favourable echocardiographic response after 12 months were smaller left ventricular end-diastolic diameter (LVEDD) (odds ratio [OR] 0.89; 95% confidence interval [CI] 0.82 - 0.97, p = 0.01), and smaller left ventricular end-systolic diameter (LVESD) (OR 0.91; 95% CI 0.85 - 0.98, p = 0.01). Lower uric acid concentration was associated with better echocardiographic response (OR 0.99; 95% CI 0.99 - 1.0, p = 0.01). Non-ischemic HF etiology (OR 4.89; 95% CI 1.39 - 17.15, p = 0.01) independently predicted positive clinical response. Multiple stepwise regression analysis demonstrated that LVEDD lower than 75 mm (OR 5.60; 95% confidence interval [CI] 1.36 - 18.61, p = 0.01) was the strongest independent predictor of favourable echocardiographic response.

CONCLUSIONS: Smaller left ventricular end-diastolic and end-systolic diameters and lower serum uric acid concentration were associated with better response to CRT. Left ventricular end-diastolic diameter and non-ischemic heart failure etiology were the strongest independent predictors of positive response to CRT.