Trudności w leczeniu ciężkiego zwężenia drogi odpływu lewej komory u chorej z kardiomiopatią przerostową

Mirosław Ziętkiewicz ^{1, 4}, Marcin Wąsowicz ^{1, 4}, Andrzej Gackowski ^{3, 4}, Rafał Drwiła ^{1, 4}, Jerzy Sadowski ^{2, 4}, Janusz Andres ^{1, 4}

Summary
Background. Abnormal mitral valve coaptation due to systolic anterior motion is a rare phenomenon usually observed in hypertrophic obstructive cardiomyopathy (HOCM). Case report. A 70-yr-old woman with HOCM and left ventricular outflow tract (LVOT) obstruction underwent percutaneous transluminal alcohol septal ablation of the first septal branch of the left coronary artery. Following surgery, her clinical condition deteriorated and inotropic support was necessary. Transoesophageal echocardiography (TEE) revealed critical obstruction of the left outflow tract (2 mm) through ventricular septal muscles and systolic anterior motion (SAM) of the mitral valve, with a gradient of 148 mm Hg (19.7 kPa). An emergency "Morrow” septal myomectomy was performed and a mechanical mitral valve implanted. The gradient decreased to 56 mm Hg (7.47 kPa) with significant improvement in left ventricular contractility. Postoperative renal failure occurred and the patient required dialysis for 7 days. A subsequent TEE revealed a minimal gradient of 12 mm Hg (1,6 kPa) and widening of the LVOT. Discussion and conclusions. SAM is usually caused by a Venturi phenomenon, occurring in the narrowed portion of the LVOT with abnormal left ventricular geometry. Obstruction of the LVOT and mitral insufficiency may lead to increases in left atrial pressure and pulmonary arterial pressure, with subsequent cardiac failure. This pathology can be diagnosed and intraoperatively controlled by TEE. Conservative pharmacologic treatment should aim at reduction of the pressure gradient across the LVOT by administration of beta-blockers and maintenance of a slow sinus rhythm. Prevention of atrial fibrillation is essential. Surgical correction of the stenosis should be undertaken when percutaneous septal ablation fails.

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