Severe Microvascular Dysfunction Evident on Myocardial Perfusion Imaging Secondary to Apical Hypertrophic Cardiomyopathy
A 58 year old male presented with a history of recurrent presyncopal episodes following strenuous exercise. He had a negative cardiac history, with no traditional risk factors. A previous coronary angiogram and echocardiogram performed in 2002 were normal.
A myocardial perfusion study was performed. His resting ECG demonstrated sinus rhythm with widespread deep T wave inversion. His presyncopal symptoms were reproduced at peak exercise with no accompanying drop in blood pressure.
Myocardial perfusion scintigraphy demonstrated extensive reversibility throughout most segments, apical, lateral and inferior walls. These findings demonstrated severe ischemia, highly suggestive of haemodynamically significant triple vessel disease.
In contrast, subsequent coronary angiogram, including intravascular ultrasound of the left main artery showed normal arteries. A transthoracic echocardiogram demonstrated hypertrophic myocardium limited to the apex, consistent with a diagnosis of the apical hypertrophic cardiomyopathy.
Based on myocardial perfusion imaging in conjunction with echocardiography, diagnosis of ischemia secondary to severe microvascular dysfunction was made.
Myocardial perfusion scintigraphy provides significant physiological information for the detection of Coronary Artery Disease (CAD) and microvascular dysfunctions.
This patient had severe ischemia with exercise in the absence of significant CAD.
Without scintigraphic correlation, this patient’s diagnosis may have been missed had angiography been the first line of investigation. The disparity in results prompted further investigation to establish a final diagnosis. This case clearly establishes the significant role of nuclear cardiology not only in the detection of CAD, but microvascular dysfunctions secondary to apical hypertrophic cardiomyopathy.