Background: Cardiac resynchronization therapy (CRT) is a new approach to treat of refractory heart failure (HF). Electrical dyssynchrony (ED) is used for selection of candidates to CRT. However, mechanical dyssynchrony (MD) may be more appropriate as it evaluates contraction. Aim: To evaluate the relationship between ED and MD in patients potentially candidates to CRT. Methods: One hundred five patients with HF (mean age 65± 20 years, NYHA class III-IV, sinus rhythm, LVEF <35%, optimized medical therapy and complete or incomplete BBB) were studied. The patients were classified in 3 groups based on QRS duration: A= <120 ms, B=120–150 ms, C= >150 ms. Three indexes of interventricular MD were measured: Qa-Qp by conventional Doppler and QT-QM and QT-QMonset by tissue Doppler imaging. Results: (1) MD was observed in all the 3 groups, with a 40% prevalence in A. (2) This was true for non-ischemic and ischemic HF etiologies. (3) QRS duration correlated weakly with MD indexes. (4) The type of electrical conduction disturbance (LBBB, RBBB) did not to influence the prevalence of MD. (5) MD had a similar prevalence in patients with left hemiblock and incomplete BBB (about 40% in both cases). Conclusions: MD is present in HF patients with narrow or intermediate QRS width. Selection of candidates to CRT should be based on MD, since the ECG underestimates prevalence of dyssynchrony.
Mechanical vs. electrical dyssynchrony for CRTselection in patients with HF
CECONI, Claudio
2007
Abstract
Background: Cardiac resynchronization therapy (CRT) is a new approach to treat of refractory heart failure (HF). Electrical dyssynchrony (ED) is used for selection of candidates to CRT. However, mechanical dyssynchrony (MD) may be more appropriate as it evaluates contraction. Aim: To evaluate the relationship between ED and MD in patients potentially candidates to CRT. Methods: One hundred five patients with HF (mean age 65± 20 years, NYHA class III-IV, sinus rhythm, LVEF <35%, optimized medical therapy and complete or incomplete BBB) were studied. The patients were classified in 3 groups based on QRS duration: A= <120 ms, B=120–150 ms, C= >150 ms. Three indexes of interventricular MD were measured: Qa-Qp by conventional Doppler and QT-QM and QT-QMonset by tissue Doppler imaging. Results: (1) MD was observed in all the 3 groups, with a 40% prevalence in A. (2) This was true for non-ischemic and ischemic HF etiologies. (3) QRS duration correlated weakly with MD indexes. (4) The type of electrical conduction disturbance (LBBB, RBBB) did not to influence the prevalence of MD. (5) MD had a similar prevalence in patients with left hemiblock and incomplete BBB (about 40% in both cases). Conclusions: MD is present in HF patients with narrow or intermediate QRS width. Selection of candidates to CRT should be based on MD, since the ECG underestimates prevalence of dyssynchrony.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
