Significance of apical cavity obliteration in apical hypertrophic cardiomyopathy

Objective Apical hypertrophic cardiomyopathy (HCM) is characterised by apical systolic obliteration and is associated with atrial fibrillation (AF), stroke, heart failure (HF), and mortality. We investigated whether apical obliteration of the left ventricular (LV) cavity could have an unfavourable impact on the clinical course of apical HCM. Methods 188 patients with apical HCM (114 males, median age 67 years) were identified retrospectively from January 2008 to December 2010. The rate of apical obliteration was defined as the net obliteration to end-diastolic apical cap thickness, and the ratio of obliteration to cavity was defined as the end-systolic obliteration to cavity height. Events were defined as a composite of new onset of AF, stroke, HF, and cardiovascular (CV) death. Results There were 43 clinical events (19 AFs, 11 HFs, 9 strokes, and 4 deaths) during a follow-up of median 4.4 years. The events patients were older, had larger left atrial volume index (LAVI), lower late diastolic mitral annular tissue Doppler velocity (a′), and higher LV end-diastolic pressure (E/e′). They had greater apical thickness and obliteration, smaller systolic cavity height, higher rate 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, rate of obliteration, and ratio of obliteration to cavity were associated with events. On multivariable analysis, the ratio of obliteration to cavity remained a significant predictor. Conclusions The ratio of obliteration to cavity could provide useful information to predict the occurrence of adverse events in apical HCM.