Hemodynamic Consequences of Hypertrophic Cardiomyopathy with Midventricular Obstruction: Apical Aneurysm and Thrombus Formation

Shahryar G Saba

doi:10.4172/2329-9126.1000161

Abstract

BackgroundHypertrophic cardiomyopathy (HCM) with midventricular hypertrophy is an uncommon phenotypic variant of the disease. Midventricular hypertrophy predisposes to intracavitary obstruction and downstream hemodynamic sequelae.Case reportWe present a case of HCM with midventricular hypertrophy and obstruction diagnosed after a CT scan of the abdomen incidentally revealed a filling defect in the left ventricular apex. Transthoracic echocardiography demonstrated mid left ventricular hypertrophy and obstruction, as well as an aneurysmal apex containing a large thrombus. Cardiovascular MRI showed a spade-shaped left ventricle with midcavitary obliteration, an infarcted apex and regions of myocardial fibrosis. Due to the risk of embolization and a relative contraindication to anticoagulation, the patient underwent surgery including thrombectomy, septal myectomy and aneurysmal ligation.ConclusionsHypertrophic cardiomyopathy with midventricular hypertrophy leads to cavity obstruction, increased apical wall tension, ischemia and ultimately fibrosis. Over time, patchy apical fibrosis can develop into a confluent scar resembling a transmural myocardial infarction in the left anterior descending coronary artery distribution. Aneurysmal remodeling of the left ventricular apex potentiates thrombus formation and risk of cardioembolism. For these reasons, hypertrophic cardiomyopathy with midventricular obstruction portends a particularly poor prognosis and should be recognized early in the disease process.

Highlights

Hypertrophic cardiomyopathy is defined as a myocardial disease characterized by unexplained left ventricular hypertrophy in association with non-dilated ventricular chambers [1]
The patient was found to have an apical thrombus with infarcted adjacent myocardium, midventricular hypertrophy and a large anterolateral papillary muscle, all consistent with hypertrophic cardiomyopathy and consequences of midventricular obstruction
According to the 2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy, the disease is defined by “unexplained left ventricular hypertrophy associated with nondilated ventricular chambers in the absence of another cardiac or systemic disease that itself would be capable of producing the magnitude of hypertrophy evident in a given patient...” [1]

Summary

Conclusions

Hypertrophic cardiomyopathy with midventricular hypertrophy and obstruction is a relatively uncommon variant of HCM that may lead to an infarcted apex and aneurysm formation. Mid ventricular obstruction with apical aneurysm formation predisposes to thrombus formation and portends a poor prognosis. Repercussions of aneurysm formation included ventricular arrhythmias, thromboembolism, predisposition to end stage disease and death. Physicians should be aware of this variant and consider these patients to be at higher risk when making management decisions

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