Apical Cavity Obliteration in Hypertrophic Cardiomyopathy
Among patients with apical hypertrophic cardiomyopathy (HCM), is apical left ventricular (LV) cavity obliteration associated with an adverse clinical course?
A cohort of 188 patients with apical HCM (114 men, median age 67 years) was identified retrospectively from January 2008 to December 2010. The extent of apical obliteration was defined as the ratio of the difference between the systolic length of apical obliteration and the diastolic apical cap thickness to the diastolic apical cap thickness (∆ apical cap thickness systole minus diastole / diastolic thickness); and the ratio of obliteration to cavity was defined as the ratio of end-systolic obliteration length to end-systolic cavity height (systolic apical obliteration length / systolic cavity height). Events were defined as a composite of new onset of atrial fibrillation (AF), stroke, heart failure (HF), and cardiovascular (CV) death.
During a follow-up of median 4.4 years, there were 43 clinical events (19 AF, 11 HF, 9 strokes, and 4 deaths). Patients who experienced an adverse event were older, had larger left atrial volume index (LAVI), lower late diastolic mitral annular tissue Doppler velocity (a’), and Doppler indices suggesting higher LV end-diastolic pressure (E/e’). They had greater apical thickness and obliteration, smaller systolic cavity height, higher extent of obliteration, and higher ratio of obliteration to cavity; events were significantly higher (54%) in the upper tertiles of the ratio of obliteration to cavity. Age, E/e’, a’, LAVI, apical thickness, extent of obliteration, and ratio of obliteration to cavity were associated with events in univariable analysis. On multivariable analysis, the ratio of obliteration to cavity remained significantly associated with clinical events.
The authors concluded that the ratio of apical obliteration to LV cavity height could provide useful information to predict the occurrence of adverse events in apical HCM.
This retrospective, single-center study found a correlation between clinical events and an echocardiographic measure of the extent of apical LV obliteration among patients with diagnosed apical-variant HCM. Perhaps this is a semi-quantitative two-dimensional (clinically accessible) means to describe the severity of apical HCM.
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