Predictors of response to cardiac resynchronization therapy: A prospective observational study

Abstract

Introduction: Cardiac resynchronization therapy (CRT) has revolutionized the treatment of cardiac dyssynchrony in chronic heart failure (HF), yet, complications and failures are reported in some patients. We aim to determine the predictors of response to CRT through clinical, electrocardiographic ECG, and echocardiographic assessment of patients following CRT and recommend the best practices to achieve optimum results for patients. Methodology: We analyzed the history, clinical examination, brain natriuretic peptide (BNP) levels, ECG, and echocardiography findings of 35 patients before CRT and on day 7 and day 180 following CRT. Observations: 71.4% of patients responded to CRT and 28.6% were nonresponders. The responders had fewer hospitalizations for HF. They showed a significant improvement in the New York Heart Association (NYHA) class, mean 6 min walk distance (6MWD), BNP level, QRS duration, and echocardiographic parameters on day 7 and day 180. The duration of HF ≤3 years, NYHA class III–IV symptoms, baseline 6MWD ≥240 m, QRS duration ≥150 ms, LVEF ≥25%, septal to posterior wall motion delay ≥130 ms, and mean pulmonary arterial pressure <50 mmHg were identified as the strong predictors of response to CRT. Recommendations: Patients with symptomatic HF should undergo early CRT to reduce recurrent hospitalizations and those with NYHA Class III–IV symptoms should be offered CRT before the duration of HF exceeds 3 years. BNP levels and echocardiography are invaluable tools to assess outcomes following therapy. A multiparametric, echocardiographic approach is helpful in selecting patients likely to undergo reverse remodeling after CRT and predicting outcomes.

Keywords

• brain natriuretic peptide level
• cardiac dyssynchrony
• cardiac resynchronization therapy
• chronic heart failure
• echocardiography