Key result
Prolonged QRS in HF is linked to an ~87% absolute prevalence of cardiac dyssynchrony.
Why the study?
What is the prevalence of echocardiographic dyssynchrony in heart failure patients with normal versus prolonged QRS duration?
Cross-Sectional (n=60)
What is the prevalence of echocardiographic dyssynchrony in heart failure patients with normal versus prolonged QRS duration?
Absolute Event Rate: 86.7% vs 23.3%
p-value: p=<0.05
Echocardiographic dyssynchrony is highly prevalent in HF patients with prolonged QRS but also exists in nearly a quarter of those with normal QRS, suggesting QRS duration alone may not fully capture mechanical dyssynchrony.
QRS duration alone may not capture mechanical dyssynchrony in HF; leaves open whether echocardiography refines CRT selection.
Cardiac resynchronization therapy (CRT) for heart failure is targeted at specific patients with mechanical dyssynchrony. We aimed to evaluate the prevalence of dyssynchrony in heart failure patients with either normal or prolonged QRS duration using Doppler imaging. Sixty heart failure patients with idiopathic dilated cardiomyopathy (30 with prolonged QRS duration 30 with normal QRS duration) underwent standard echocardiography and tissue Doppler imaging examinations. Difference between left and right ventricular pre-ejection intervals of more than 40 msec was considered a marker of interventricular dyssynchrony. Intraventricular dyssynchrony was defined as a delay of 60 msec between the time to peak velocities of the septum and left ventricular lateral wall. Patients who have either intra- or interventricular dyssynchrony were defined as with cardiac dyssynchrony. Dyssynchrony was observed in 7 (23.3%) heart failure patients with normal QRS duration versus 26 (86.7%) patients with prolonged QRS duration. There was significant difference between the prevalence of dyssynchrony derived from echo criteria in two groups (P<0.05). Although patients with prolonged QRS duration have a high prevalence of dyssynchrony, yet some still have good cardiac synchronicity. Moreover, dyssynchrony also exists in a small percentage of heart failure patients with normal QRS duration. To identify the potential responders for CRT, both QRS duration and cardiac synchronicity should be assessed.
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Niu et al. (2007) conducted a cross-sectional in Heart failure with idiopathic dilated cardiomyopathy (n=60). Prolonged QRS duration vs. Normal QRS duration was evaluated on Cardiac dyssynchrony (intra- or interventricular dyssynchrony) (p=<0.05). Prolonged QRS duration in heart failure patients was associated with a higher prevalence of cardiac dyssynchrony compared to normal QRS duration (86.7% vs 23.3%; P<0.05).
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