Abstract
Takotsubo cardiomyopathy (TCM) is usually characterized by left ventricular anteroapical dysfunction in the absence of significant coronary disease commonly precipitated by an emotional or stressful trigger. Hypertrophic cardiomyopathy (HCM) is usually diagnosed on the basis of symptoms, family history, echocardiography, or by the presence of a characteristic murmur. We report a unique case of TCM occurring in a patient with previously undiagnosed HCM with left ventricular outflow tract (LVOT) obstruction who presented with an acute coronary syndrome and ultimately underwent successful alcohol septal ablation. The potential pathophysiologic correlations are discussed.
1
Case report
A 48-year-old man presented to the emergency department with persistent, sharp, left-sided chest pain, shortness of breath, and diaphoresis that awoke him from sleep less than 1 h prior. He had a history of hyperlipidemia, but otherwise no known cardiac disease or previous similar symptoms. He led an active lifestyle, exercised frequently, and denied antecedent physical or emotional stressors. On exam, his heart rate was 61 beats/min, blood pressure was 105/71 mmHg, and temperature 35.8°C. Lungs were clear to auscultation and cardiac exam revealed a normal S1 and S2 with a Grade II/VI systolic murmur at the right upper sternal border that at that time was not further characterized. His electrocardiogram on presentation revealed Q waves in V 1 –V 2 and 1–2 mm of ST elevation in V 2 –V 4 ( Fig. 1 A ). Initial laboratory work was remarkable for creatine kinase-MB fraction of 6.25 ng/ml (normal ≤4.9 ng/ml) and troponin I ultra 1.14 ng/ml (normal ≤0.06 ng/ml) which subsequently trended down. Given concern for a possible acute anterior ST-elevation myocardial infarction, standard therapy was initiated with heparin, aspirin, clopidogrel, metoprolol, and high-dose statin, and he was taken emergently to the cardiac catheterization laboratory. Angiography revealed only mild luminal irregularities in all coronaries, but ventriculography demonstrated severe hypokinesis of the apical, anterior apical, and inferior apical walls with hyperdynamic function of the base ( Fig. 2 ). His overall ejection fraction was estimated at 35%. Simultaneous ventricular and systemic arterial pressure measurements revealed a peak-to-peak left ventricular to aortic resting gradient of 70 mmHg, increasing to >140 mmHg after an induced premature ventricular contraction ( Fig. 3 ). Left ventricular end-diastolic pressure was elevated at 20 mmHg.
Immediately after cardiac catheterization, transthoracic echocardiography demonstrated asymmetric septal hypertrophy (septal thickness 2.0 cm, posterior wall 0.8 cm) and akinesis of the distal anterior, distal septal, distal inferior, distal lateral, and apical walls of the left ventricle with an ejection fraction of 43% ( Fig. 4 A and B). Systolic anterior motion of the mitral valve (SAM, Fig. 4 C) and mid-systolic notching of the aortic valve were also visualized. Left ventricular outflow tract (LVOT) Doppler revealed a peak gradient of 96 mmHg, increasing to 105 mmHg with the Valsalva maneuver ( Fig. 4 D). The patient was admitted to the cardiac intensive care unit with a clinical diagnosis of takotsubo cardiomyopathy (TCM) in the setting of previously undiagnosed asymmetric hypertrophic cardiomyopathy (HCM) with obstruction. The day following admission, a repeat echocardiogram demonstrated a persistent gradient across the LVOT (66 mmHg at rest, 100–130 mmHg with Valsalva) and asymmetric septal hypertrophy, but now with near normalization of LV function with minimal apical hypokinesis and an ejection fraction of 66% ( Fig. 5 ). Repeat electrocardiogram demonstrated resolution of the acute anterior ST elevation and Q-wave in V 2 with development of deep T-wave inversions throughout the precordial leads ( Fig. 1 B). He was discharged 3 days after admission following an uncomplicated hospital course, continuing medical therapy that included a beta-blocker, angiotensin-converting enzyme inhibitor, statin, aspirin, and other risk factor modification.
