A novel mechanism of heart failure with normal ejection fraction

¹ Taunton & Somerset Hospital, United Kingdom

^* To whom correspondence should be addressed. E-mail: david.maciver{at}tst.nhs.uk.

Accepted 20 February 2007

	Abstract

Background Patients with heart failure and a normal left ventricular ejection fraction have significantly reduced left ventricular long-axis function. This paper proposes an explanation for this apparent paradox and suggests a novel mechanism of 'diastolic' heart failure.

Method The effect of changes in left ventricular hypertrophy on stroke volume and ejection fraction in non-dilated left ventricles was calculated using the area-length method. Further, the effect of a reduction in long-axis shortening on these parameters was determined.

Results Increasing left ventricular hypertrophy resulted in augmentation of systolic wall thickening and ejection fraction but not stroke volume when long-axis shortening was normal. In the presence of abnormal long-axis function, stroke volume was reduced but ejection fraction was preserved.

Conclusion The model predicts that the normal ejection fraction in patients with heart failure may be explained by the presence of left ventricular hypertrophy. The resulting amplified radial thickening in the setting of reduced long-axis shortening explains the preservation of ejection fraction. The reduced stroke volume in the pre-compensated state rather than diastolic dysfunction may be the cause of heart failure.

Abbreviations LVEF, left ventricular ejection fraction; LVH, left ventricular hypertrophy; HFNEF, heart failure with normal ejection fraction.

Keywords: Diastolic dysfunction, Heart Failure, Left ventricular function, Left ventricular hypertrophy, Myocardial Velocity Imaging

Related Article

Ejection fraction: a measure of desperation?

Charlotte H Manisty and Darrel P Francis
Heart 2008 94: 400-401. [Extract] [Full Text] [PDF]