A 62-year-old man was referred for management of symptomatic hypertrophic obstructive cardiomyopathy (HOCM). For the past 20 years, he has had a history of syncope after recovering from anesthesia for minor outpatient surgery. He was resuscitated with fluids before discharge and did well. About 8 years ago, after another postoperative syncopal episode, a murmur was detected and an echocardiogram confirmed the diagnosis of HOCM. He could only tolerate a low dose of β-blockers due to his low blood pressure. His dyspnea has progressively worsened, and now he is dyspneic with usual activity (New York Heart Association class III). He also feels dizzy and needs to hold on to the hand rail while climbing up stairs. He does not have angina or palpitations. There is no family history of HOCM or sudden death.
Examination reveals a thin and lean gentleman. He has a bisferiens pulse. His pulse rate is 60 bpm, and his blood pressure is 100/65 mm Hg. He has no signs of heart failure. The second heart sound is paradoxically split, and he has a fourth heart sound. He has a 3/6 systolic murmur over the precordium and a blowing pansystolic murmur at the apex. The murmur increases significantly with Valsalva and with standing.
The electrocardiogram reveals left ventricular hypertrophy with strain pattern. An echocardiogram reveals asymmetric basal septal hypertrophy (Figure 28-1) and systolic anterior motion of the mitral valve (Figure 28-2)with left ventricular outflow gradient of 56 mm Hg at rest (Figure 28-3) and 64 mm Hg with Valsalva (Figure 28-4). After discussing all options for septal reduction therapy, he elects to have alcohol septal ablation.
Parasternal long axis view showing asymmetric septal hypertrophy (ASH) of basal anterior septum.
Three-chamber view demonstrating systolic anterior motion (SAM) of the mitral leaflet producing left ventricular outflow tract obstruction.
Continuous-wave Doppler tracing showing the dagger-shaped left ventricular outflow gradient of 56 mm Hg.
Continuous-wave Doppler tracing showing the dynamic nature of the left ventricular outflow tract obstruction. The peak gradient at rest is 36 mm Hg but increases to 64 mm Hg with Valsalva provocation.
HOCM was initially described in by Brock in 1957 in a surgical patient.1 In 1958, Teare described the anatomy of 8 young patients who had a sudden death and asymmetric septal hypertrophy.2 In the 1960s, Braunwald described the pathophysiology of this new disease state.3 For many years, it was debated whether the left ventricular outflow tract (LVOT) obstruction ...