From the Guidelines
No, HCOM (hypertrophic cardiomyopathy) is not the same thing as LVOT (left ventricular outflow tract). These are distinct cardiac terms with different meanings. HCOM, also commonly abbreviated as HCM, is a disease characterized by abnormal thickening of the heart muscle, particularly the left ventricle, making it harder for the heart to pump blood [ 1 ]. LVOT refers to the anatomical pathway through which blood flows from the left ventricle to the aorta. While they are different concepts, they are related because in many cases of HCOM, the thickened heart muscle can obstruct the LVOT, causing what's called LVOT obstruction, which is present in a significant proportion of patients with HCM, primarily caused by SAM of the mitral valve [ 1 ].
Key Differences and Relationship
- HCOM is a disease of the heart muscle, while LVOT is an anatomical structure.
- LVOT obstruction is a complication that can occur in HCOM, characterized by a peak LVOT gradient of ≥30 mm Hg [ 1 ].
- The management of HCOM with LVOT obstruction differs from that without obstruction, with resting or provoked gradients ≥50 mm Hg being the threshold for contemplating advanced pharmacological or invasive therapies if symptoms are refractory to standard management [ 1 ].
Clinical Implications
The distinction between HCOM and LVOT is crucial for proper diagnosis and treatment planning. Understanding the relationship between these two concepts can help guide the use of provocative maneuvers, such as standing, Valsalva strain, or exercise with simultaneous auscultation or echocardiography, to identify latent LVOTO and determine eligibility for advanced therapies [ 1 ].
From the Research
Definition and Relationship
- HCM (Hypertrophic Cardiomyopathy) is a genetic cardiomyopathy characterized by an increase in the left ventricular wall thickness in absence of increased loading conditions 2.
- Left ventricular outflow tract obstruction (LVOTO) is a key pathophysiologic determinant in patients with HCM, and it is detected in many patients with HCM 2, 3.
- LVOTO is not the same as HCM, but rather a common feature of HCM that can lead to reduced functional capacity, sudden cardiac death, and advanced heart failure 2, 4.
Clinical Features and Diagnosis
- Patients with HCM and LVOTO may present with exertional dyspnea, exertional syncope, and heart failure symptoms 3.
- The diagnosis of HCM and LVOTO can be made using echocardiography, cardiac magnetic resonance, and other imaging modalities 5, 6.
- The management of obstructive HCM remains challenging and requires a multidisciplinary team approach, including cardiologists, cardiac surgeons, and other specialists 3.
Treatment and Management
- Treatment options for HCM and LVOTO include pharmacological therapy, surgical myectomy, alcohol septal ablation, and other invasive interventions 2, 3.
- The choice of treatment depends on the severity of symptoms, the presence of LVOTO, and other individual patient factors 3, 5.
- Recent studies have highlighted the importance of considering mitral valve and papillary muscle abnormalities in the management of HCM patients with LVOTO 5.