From the Guidelines
Hypertrophic obstructive cardiomyopathy (HOCM) and concentric left ventricular hypertrophy (LVH) are distinct cardiac conditions that require different management approaches, with HOCM being a genetic disorder characterized by asymmetric septal hypertrophy and dynamic left ventricular outflow tract obstruction, whereas concentric LVH represents a symmetric thickening of the left ventricular walls in response to pressure overload conditions. The key differences between HOCM and concentric LVH lie in their etiology, pathophysiology, and clinical presentation, as outlined in the 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy 1. HOCM is characterized by asymmetric septal hypertrophy, which can lead to dynamic left ventricular outflow tract obstruction and increased risk of sudden cardiac death. In contrast, concentric LVH is typically associated with symmetric thickening of the left ventricular walls, usually in response to pressure overload conditions such as hypertension or aortic stenosis, as described in the European Association of Cardiovascular Imaging (EACVI) and American Society of Echocardiography (ASE) recommendations on the use of echocardiography in adult hypertension 1.
Some of the key distinguishing features between HOCM and concentric LVH include:
- Asymmetric septal hypertrophy in HOCM versus symmetric wall thickening in concentric LVH
- Presence of outflow obstruction in HOCM, which is typically absent in concentric LVH
- Different management approaches, with HOCM often requiring beta-blockers, calcium channel blockers, disopyramide, or surgical/interventional procedures, whereas concentric LVH management focuses on treating the underlying cause, such as blood pressure control
- Importance of genetic testing in HOCM for family screening, whereas it is not typically indicated in concentric LVH
Echocardiography remains the primary diagnostic tool for differentiating between HOCM and concentric LVH, with cardiac MRI providing additional tissue characterization when needed, as recommended by the 2020 AHA/ACC guideline 1. The management of HOCM and concentric LVH should be guided by the underlying pathophysiology and clinical presentation, with a focus on relieving outflow obstruction and preventing sudden cardiac death in HOCM, and controlling blood pressure and reducing left ventricular wall thickness in concentric LVH.
From the Research
HOCM vs Concentric LVH: Key Differences
- HOCM (Hypertrophic Obstructive Cardiomyopathy) is characterized by a left ventricular outflow tract (LVOT) gradient at rest or during provocation, as with Valsalva maneuver or exercise 2.
- Concentric LVH (Left Ventricular Hypertrophy) is a condition where the left ventricle wall thickness increases in response to high blood pressure, without a significant LVOT gradient 3.
Management of HOCM
- Management of HOCM encompasses activity restriction, prevention of sudden cardiac death, control of symptoms, and screening of relatives 2.
- Pharmacologic treatment of symptoms in patients with HOCM consists of negative inotropic drugs, such as beta blockers, disopyramide, and nondihydropyridine calcium channel blockers 2, 4.
- Septal reduction therapy (SRT) may be considered for patients with intolerable symptoms despite optimal conservative therapy 2, 5.
Comparison with Concentric LVH
- Concentric LVH is often associated with hypertension, and blood pressure control with lifestyle changes and antihypertensive agents can prevent and regress LVH 3.
- In contrast, HOCM is a primary cardiac disorder that requires specific management strategies, including septal reduction therapy and implantable cardioverter-defibrillators (ICDs) for high-risk patients 2, 4.
Treatment Outcomes
- Disopyramide therapy has been shown to improve functional capacity in patients with obstructive HOCM, with 62% of patients achieving a 1-stage NYHA improvement compared to 26% in the control group 6.
- However, there is limited direct comparison between HOCM and concentric LVH treatment outcomes, highlighting the need for further research in this area.