Key result
Asymptomatic LBBB demonstrates intermediate mechanical dyssynchrony between healthy volunteers and symptomatic HF patients.
Why the study?
Does mechanical dyssynchrony and global LV function measured by RT3DE differ between healthy volunteers, asymptomatic LBBB patients, and symptomatic HF patients with LBBB?
Cross-Sectional (n=61)
Does mechanical dyssynchrony and global LV function measured by RT3DE differ between healthy volunteers, asymptomatic LBBB patients, and symptomatic HF patients with LBBB?
Absolute Event Rate: 7.3% vs 5.6%
Real-time 3D echocardiography demonstrates that mechanical dyssynchrony is most severe in symptomatic HF patients with LBBB, and an SDI >10.8% is associated with HF symptoms.
Dyssynchrony severity may track symptom onset in LBBB; hypothesis-generating for RT3DE thresholds, requiring longitudinal validation before clinical use.
BACKGROUND: A left bundle branch block (LBBB) affects both global left ventricular (LV) function and mechanical dyssynchrony. The aim was to evaluate global LV function and mechanical dyssynchrony with real-time 3D echocardiography (RT3DE), in asymptomatic LBBB patients, healthy volunteers and patients with symptomatic heart failure (HF) and a LBBB. Furthermore, the relation between presence or absence of symptoms of HF and mechanical dyssynchrony was investigated. METHODS: RT3DE was performed in 61 consecutive patients: 16 healthy volunteers, 22 patients with an asymptomatic LBBB and 23 patients with symptomatic HF and a LBBB. Global LV function and the systolic dyssynchrony index (SDI) were measured. RESULTS: In healthy volunteers, mean LV ejection fraction was 54 +/- 5%, in asymptomatic LBBB patients 50 +/- 9%, and in HF patients 29 +/- 9%. SDI was 5.6 +/- 3.6%, 7.3 +/- 3.2% and 12.8 +/- 4.8% for healthy volunteers, asymptomatic LBBB patients and HF patients respectively. SDI differed significantly between HF patients and both other groups. A cut-off value for SDI for presence of symptoms of HF was 10.8%. CONCLUSION: Asymptomatic LBBB patients have more depressed global LV function than healthy volunteers have; patients with symptoms of HF and a LBBB have severe global LV dysfunction. Asymptomatic LBBB patients have an intermediate mechanical dyssynchrony; HF patients with a LBBB have the most severe mechanical dyssynchrony. A substantial amount of mechanical dyssynchrony might be accompanied by the presence of symptoms of HF.
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VANDIJK et al. (2007) conducted a cross-sectional in Left bundle branch block (LBBB) and heart failure (n=61). Left bundle branch block (LBBB) vs. Healthy volunteers was evaluated on Systolic dyssynchrony index (SDI). Asymptomatic LBBB patients had intermediate mechanical dyssynchrony (SDI 7.3%) compared to healthy volunteers (5.6%), while symptomatic HF patients with LBBB had the most severe dyssynchrony (12.8%).
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