There are no parameters predicting the individual probability of "full response" to cardiac resynchronization therapy (CRT). The aim of this work was to find prognostic factors of full clinical and echocardiographic responses (i.e., ≥50\% left ventricular ejection fraction [LVEF] and New York Heart Association class I) after 1 year of CRT. This was a prospective follow-up study that involved 2 hospitals. Patients (n = 75) with advanced heart failure (64 ± 9 years of age, 87\% men, LVEF 24 ± 7\%) who received CRT were followed for 17 ± 9 months. Univariate and multivariate regression analyses were used to identify predictors of full CRT response. A nomogram predicting the individual probability of full CRT response during follow-up was calculated. There were 13 patients with restoration of normal LVEF versus 62 without (mean LVEF 56\% ± 5\% vs 31\% ± 8\%, respectively, p <0.001). Predictors of full response included cause of heart disease, baseline QRS width, and degree of QRS shortening in response to CRT. Patients with nonischemic heart disease, baseline QRS width ≤150 ms, and QRS shortening ≥40 ms in response to CRT had a >75\% probability of restoration of normal LVEF. In conclusion, our nomogram using a combination of cause, baseline QRS width, and degree of QRS shortening in response to CRT allows assessment of individual probability of full response. This observation awaits further confirmation from larger series.
