Cardiac resynchronization therapy: factors determining the positive response to therapy according to the ESC/PTK guidelines 2013

Abstract

Heart failure (HF) is one of the main causes of mortality and morbidity in the world population. Cardiac resynchronization therapy (CRT) is a HF therapy with proved influence on mortality reduction and HF hospitalization. Based on update guidelines, CRT is recommended to patients with the sinus rhythm, QRS complex prolongation ≥ 150 ms, left bundle branch block (LBBB), seriously impaired left ventricular ejection fraction (LVEF) ≤ 35%, in New York Heart Association (NYHA) class II–III or ambulatory class IV. In update guidelines, there are also CRT therapy recommendations for patients with narrower QRS complex (120–150 ms), with QRS morphology different from LBBB and with chronic atrial fibrillation. The degree of response for CRT therapy and benefits of this method (responders) are still the aim of many clinical trials. It is proved that the best responders of CRT therapy — including morbidity and mortality reduction are women, patients with non-ischaemic cardiomiopathy, with LBBB and QRS prolongation more than 150 ms (the longer QRS complex, the better response). New echocardiographic parameters which might be the predictors of positive response for CRT are still in request. Current echocardiographic estimation is obligatory in patients’ short and long term monitoring after CRT implantation and during programming the optimal parameters of stimulation. One of a very promising parameter which may be useful in predicting the effect of CRT therapy is left ventricle torsion. But it still needs verification among broader range of patients.