Asymmetrical septal hypertrophy is the most common variant of hypertrophic cardiomyopathy accounting for approximately 80% of cases. Apical HCM (ApHCM) is a less common pattern of HCM and may represent a genetically unique population. In Japan, ApHCM affects 13% to 25% of the total HCM patient group; in North America, it affects 3% to 11%. ApHCM presents with several distinct features; it has been reported that about 10% of patients with ApHCM have apical regional dysfunction or the formation of an apical out-pouching or aneurysm in the presence of normal coronary arteries. Maron et al. described a 2% incidence of apical aneurysms among 1,299 patients with HCM with any pattern of hypertrophy (i.e., including ApHCM and other patterns of HCM). That report showed that patients with apical aneurysms had a combined adverse event rate of 10.5% per year, including sudden death, appropriate implantable cardioverter-defibrillator discharges, nonfatal thromboembolic stroke, and progressive heart failure and death. Therefore, knowledge of the incidence and optimal identification of an apical out-pouching seem to be important for counseling patients on the expected risks of their disease. Another report from the Mayo clinic showed a high complication rate in patients with apical hypertrophy however this was regardless of whether there was an apical out-pouching or not.
The mechanism of development of apical aneurysms in hypertrophic cardiomyopathy is not clear. It is postulated that a continuum of apical abnormalities may exist, starting with hypokinesis in the thick apical walls due to ischemia, which may lead to increasing localized dilatation of the apex and ultimately, in selected patients, an apical aneurysm with scarring. Ischemia as an integral feature of this process is suspected on the basis of enhanced myocardial oxygen demand in the hypertrophic apex. It is supported by the common finding (88% in the Mayo clinic series) of apical ischemia on myocardial perfusion imaging and evidence of apical fibrosis on cardiac MRI. Sustained cavity obliteration has also been described as a factor leading to apical aneurysm formation, along with hypertrophy, ischemia, and prolonged QTc interval.
Although echocardiography was initially the preferred diagnostic tool. Cardiac MRI is now emerging as the most informative modality. First some cases were missed by echocardiography because of technical difficulty in clearly visualizing the true and not foreshortened apex. The use of contrast may help to overcome this difficulty. MRI however in addition to superior visualization, may delineate the extent of fibrosis and the possible presence of thrombus.
Have any of you encountered such a case?
If he was not in atrial fibrillation would you put this patient on anticoagulation?
Would you agree on recommending a defibrillator??
1. Apical Hypertrophic Cardiomyopathy: Prevalence and Correlates of Apical Outpouching. Joseph Binder, MD et al. J Am Soc Echocardiogr 2011;24:775-81.
2. Prevalence, Clinical Significance, and Natural History of Left Ventricular Apical Aneurysms in Hypertrophic Cardiomyopathy.
Martin S. Maron, Circulation. 2008;118:1541-1549