Intramural myocardial shortening in hypertensive left ventricular hypertrophy with normal pump function

Area of Science:

• Cardiology
• Cardiovascular Imaging
• Medical Physics

Background:

• Hypertensive left ventricular hypertrophy (LVH) can present with normal or depressed intrinsic myocardial systolic function.
• Magnetic resonance (MR) tagging is a non-invasive imaging technique capable of visualizing intramural myocardial shortening in vivo.

Purpose of the Study:

• To assess intramural myocardial shortening in hypertensive patients with LVH using MR tagging.
• To compare circumferential and longitudinal myocardial shortening in hypertensive LVH subjects versus normal controls.

Main Methods:

• Tagged left ventricular MR images were acquired in 30 hypertensive subjects with LVH and 10 normal subjects.
• Spatial modulation of magnetization was used for image acquisition.
• Circumferential and longitudinal myocardial shortening were quantified at various transmural and longitudinal locations.

Main Results:

• Circumferential myocardial shortening was significantly reduced in hypertensive LVH subjects compared to normal controls at the endocardium, midwall, and epicardium.
• The normal base-to-apex gradient of circumferential shortening was absent in hypertensive LVH.
• Longitudinal myocardial shortening was uniformly depressed across basal, midventricular, and apical regions in hypertensive LVH patients.

Conclusions:

• Even with preserved global pump function, hypertensive LVH is associated with depressed intramural myocardial shortening.
• Both circumferential and longitudinal myocardial shortening are impaired in hypertensive LVH.