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Will mechanical dyssynchrony one day impact our management of chronic heart failure patients?

Mechanical dyssynchrony along with its role in cardiac resynchronization therapy (CRT) has been studied for over 10 years now.1 Although there are ‘believers’ in imaging techniques and echocardiography specifically, there are no recommendations for their use in clinical practice or guidelines for CRT.2

QRS duration remains the gold-standard for selecting patients for CRT and predicting their responses.² The key importance of QRS width and morphology, so as to predict responses to CRT, has been demonstrated recently.3 According to the results of the RethinQ trial involving 172 patients with heart failure and narrow QRS, CRT did not improve peak oxygen consumption or LV remodelling at the 6-month follow-up.4 It has also been demonstrated that the correlation between mechanical dyssynchrony and QRS width was less than perfect.5 Thus, despite the 30% rate of non-response to CRT, it is challenging for imaging techniques to demonstrate substantial value, …