Usefulness of a Novel "Response Score" to Predict Hemodynamic and Clinical Outcome from Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) is an important treatment for patients with congestive heart failure and ventricular dyssynchrony, but response to CRT is highly variable. We assessed whether a scoring system that encompasses a combination of patient selection and procedural variables would improve prediction of CRT response. Thirty-nine patients who underwent CRT with echocardiographic assessment of baseline contractility and left ventricular (LV) dyssynchrony, intraprocedural assessment of LV lead electrical delay, and postprocedural chest radiography were included. Baseline LV dyssynchrony was measured by Doppler tissue velocity imaging as the maximum time difference between peak systolic velocity of anterior, lateral, posterior, and septal walls. The hemodynamic effect of CRT was measured by Doppler analysis of mitral regurgitation as percent change in maximal +dP/dt (ΔdP/dt) with CRT on versus off. Acute responders to CRT were defined as Δdp/dt ≥25%. Clinical response was measured as a combined end point of hospitalization for heart failure and all-cause mortality. A 4-point response score was generated using variables associated with ΔdP/dt and assigning 1 point for a dorsoventral LV/right ventricular interlead distance >10 cm, 1 point for a LV lead electrical delay ≥50%, 1 point for a baseline maximum +dP/dt <600 mm Hg/s, and 1 point for a maximum time difference >100 ms. In conclusion, there was a significant association between response score (0 to 4 points) and acute hemodynamic response to CRT (p <0.0001). Kaplan-Meier analysis associated a higher response score with improved 12-month event-free survival after CRT implantation (p = 0.0019).