Cor Vasa 2011, 53(10):535-541 | DOI: 10.33678/cor.2011.133

Are our criteria for selection of candidates for cardiac resynchronization therapy correct?

Jolana Lipoldová^*, Jaroslav Meluzín, Miroslav Novák, Eva Ozábalová

I. interní kardioangiologická klinika, Lékařská fakulta Masarykovy univerzity a Fakultní nemocnice u sv. Anny, Brno, Česká republika

Introduction: A number of studies have documented the effect of cardiac resynchronization therapy (CRT) on improving functional status and inducing reverse left ventricular remodeling. Using current indication criteria, the proportion of non-responders, i.e., those not responding to CRT, has been reported to be 30-40%.

Aim: To assess, in patients with CRT devices, the effect of CRT on changes in NYHA class and echocardiographic parameters, to assess the effect of heart failure etiology and baseline rhythm, and to determine the ability of QRS width and ventricular dyssynchrony parameters to predict the effect of CRT.

Patients and methods: A total of 194 patients with successful CRT device implantation were evaluated. Their NYHA class, QRS width and echocardiographic parameters including those of ventricular dyssynchrony (septal-to-posterior wall motion delay [SPWMD], time difference in peak systolic septal-to-lateral wall velocity in tissue Doppler imaging [Ts-bas-lat], and interventricular mechanical delay [IVMD]) were determined prior to implantation and at 3 and/or 12 months after the procedure.

Results: The improvement in NYHA class at 3 months was significant compared with baseline, and significant compared with 12 months post-implant. There were 61% and 49% of responders (patients with improved NYHA class) at 3 and 12 months post-implant, respectively. Compared with non-responders, responders showed improved left ventricular ejection fraction (LVEF) and decreased end-diastolic and end-systolic dimensions (LVEDD, LVESD). The effect of CRT was comparable in patients with ischemic and non-ischemic cardiomyopathy, and CRT was less effective in patients with atrial fibrillation versus those with sinus rhythm. The improvement in ventricular dyssynchrony parameters was apparent in all patient subpopulations. QRS width and SPWMD showed relatively good sensitivity but poor specificity whereas this was just the opposite with IVMD. The predictive power of QRS width and IVMD was higher in patients with non-ischemic cardiomyopathy.

Conclusion: Cardiac resynchronization therapy improves NYHA class, LVEF, LVEDD, and LVESD; however, the improvement is apparent only in responders. The effect of CRT is not dependent on the etiology of heart failure. The benefit of CRT is less in patients with atrial fibrillation. None of the tested parameters of ventricular dyssynchrony showed a good predictive power. Our conclusions are similar to those reported by the multicenter controlled PROSPECT and SCART trials.

Keywords: Cardiac resynchronization therapy; Ventricular dyssynchrony; Selection of candidates for CRT

Published: October 1, 2011  Show citation