Role of cardiac magnetic resonance in differentiating between acute coronary syndrome and apical hypertrophic cardiomyopathy

Case report

A 72-year-old female patient with a history of hypertension was admitted to the hospital with suspicion of non-ST-segment elevation acute coronary syndrome. On ECG, left ventricle hypertrophy and negative T waves in V2–V6 were present. Levels of cardiac enzymes were markedly increased with troponin (Tn) I at admission 2.06 µg/l and with a subsequent drop to values of 0.99 µg/l and 0.71 µg/l. Renal function parameters were normal. She did not complain of chest pain, but due to long lasting diabetes treated with insulin silent myocardial ischemia was suspected. At admission, an episode of supraventricular tachycardia with a heart rate of 180 beats per minute was detected (Figure 1 A). Negative T waves in V2–V6 (Figure 1 B), increased troponin level and long-lasting diabetes as a risk factor for atherosclerosis with potential silent ischemia were indicators for coronary angiography. In urgent coronary angiography no significant coronary artery stenoses were confirmed. The tentative diagnosis of myocardial ischemia/injury due to epicardial coronary artery disease became doubtful. Transthoracic echocardiography was technically difficult due to suboptimal acoustic condition for the imaging. All heart valves were normal. Both ventricles and atria were non-dilated. Ejection fraction was 70%. The intraventricular septum at the basal segment was non-thickened (end systole 13 mm, end diastole 8 mm). Thickness of posterior wall was normal (end systole 14 mm, end diastole 7 mm). Importantly, the apical segment of the intraventricular septum was hypertrophied (15–16 mm at end diastole; quality of imaging was suboptimal) suggesting the apical form of hypertrophic cardiomyopathy (HCM). In Doppler echocardiography moderate pulmonary hypertension was detected. To confirm the presence of apical HCM cardiac magnetic resonance (CMR) with contrast agent (gadolinium) was performed. Cardiac magnetic resonance examination confirmed apical hypertrophy and excluded either ischemic injury or fibrotic area of myocardium due to lack of regions of late contrast enhancement (Figures 1 C–F). No ventricular arrhythmias were observed in the ECG Holter recording. Both family history of sudden cardiac death and past history of syncope were negative.

Discussion

Cardiac magnetic resonance is a very useful diagnostic modality in patients with non-definitive HCM due to technical difficulties in echocardiographic imaging. In about 20% of patients suspected with...


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