HCM with left ventricular outflow tract obstruction at rest

Shown from top to bottom are four surface ECG leads and the left ventricular (LV) and aortic (Ao) pressure tracings from a patient with hypertrophic cardiomyopathy. The maximum LV systolic pressure is 230 mmHg; the Ao pressure, measured simultaneously with the maximum LV pressure, is 85 mmHg, thereby resulting in an LV outflow gradient of 145 mmHg. The LV systolic pressure varies by 20 to 30 mmHg with each beat (alternans), a finding occasionally found in HCM. The aortic pulse pressure is narrow (25 mmHg), and the pressure tracing reveals the spike-and-dome configuration of LV outflow obstruction.