Role of 2D Echocardiography in Hypertrophic Obstructive Cardiomyopathy (HOCM)

Diagnostic Role

The American College of Cardiology recommends comprehensive 2D echocardiography to establish the diagnosis of HOCM by determining the pattern of hypertrophy, presence of left ventricular apical aneurysms, LV systolic and diastolic function, mitral valve function, and presence and severity of left ventricular outflow tract obstruction (LVOTO) 1, 2
Measurement of maximum diastolic wall thickness using 2D short-axis views in all LV segments from base to apex is recommended to characterize the extent and pattern of hypertrophy 3, 4

LVOT gradients are dynamic and influenced by loading conditions; recumbent resting echocardiography tends to underestimate the presence and severity of ambulatory LVOTO, with up to 50% of obstructive cases missed on resting studies 1, 5
If resting gradient is <50 mm Hg, provocative maneuvers are essential to uncover LVOTO, including Valsalva maneuver in sitting and semi-supine positions 4
Exercise echocardiography is recommended for symptomatic patients to detect provocable LVOTO and exercise-induced mitral regurgitation 2, 3

Comprehensive evaluation of LV diastolic function is recommended, including pulsed Doppler of mitral valve inflow, tissue Doppler velocities at mitral annulus, pulmonary vein flow velocities, and pulmonary artery systolic pressure 3, 4
Left atrial size and volume should be assessed as part of the comprehensive evaluation of LV diastolic function 3, 4

Routine follow-up with serial TTE every 1-2 years is recommended for asymptomatic patients to assess changes in LV systolic and diastolic function, wall thickness, chamber size, and concomitant valvular disease 1, 2, 4
For patients undergoing septal reduction therapy (SRT), TTE within 3-6 months after the procedure is recommended to evaluate procedural results 6
Perioperative transesophageal echocardiography (TEE) is recommended for patients undergoing septal myectomy to guide surgical strategy, assess post-surgical complications, and detect residual LVOTO 3, 4

For patients with suboptimal images or suspected apical hypertrophy or aneurysm, TTE with LV cavity opacification using intravenous ultrasound-enhancing agents should be considered 1, 2
TEE can be useful if TTE is inconclusive for clinical decision-making regarding medical therapy, planning for myectomy, excluding subaortic membrane, or assessing mitral regurgitation secondary to structural abnormalities 1, 2

TTE is recommended for first-degree relatives of patients with HCM as part of initial family screening and periodic follow-up 6
In genotype-positive, phenotype-negative individuals, echocardiography is recommended at periodic intervals, every 1-2 years in children and adolescents, and every 3-5 years in adults 1, 2, 6