From the Guidelines
Hypertrophic Obstructive Cardiomyopathy (HOCM) is typically characterized by abnormal electrocardiogram (ECG) findings, including left ventricular hypertrophy (LVH) and repolarization changes, in 75% to 95% of patients, as noted in the 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR guideline 1. The ECG findings in HOCM may include:
- Deep S waves in V1-V2 and tall R waves in V5-V6, often meeting voltage criteria for LVH
- ST segment depression and T wave inversions in the lateral leads (I, aVL, V5-V6) reflecting secondary repolarization abnormalities
- Pathologic Q waves in the inferior and lateral leads, mimicking prior myocardial infarction, but actually representing abnormal septal depolarization due to the hypertrophied septum
- Left atrial enlargement, seen as a prolonged, notched P wave in lead II (P mitrale), due to diastolic dysfunction These findings are supported by the 2024 guideline, which highlights the importance of ECG in identifying patients with HOCM and monitoring for potential complications, such as atrial fibrillation and ventricular tachyarrhythmias 1. The use of ambulatory electrocardiographic monitoring is also recommended in the guideline, particularly in patients with symptoms, to detect ventricular tachyarrhythmias and identify patients at higher risk of sudden cardiac death (SCD) 1. The 12-lead ECG is a crucial diagnostic tool in HOCM, and its findings should be interpreted in conjunction with clinical symptoms and other diagnostic tests, such as echocardiography, to confirm the diagnosis and guide management 1.
From the Research
Electrocardiogram Findings in HOCM
The electrocardiogram (ECG) is a crucial diagnostic tool in the evaluation of patients with hypertrophic cardiomyopathy (HCM), including those with hypertrophic obstructive cardiomyopathy (HOCM) 2.
- The ECG can show various abnormalities, including left ventricular hypertrophy, Q-waves, and repolarization abnormalities, which can be helpful in diagnosing HCM and differentiating it from other conditions 2.
- Specific electrical anomalies on the ECG can differentiate HCM from phenocopies such as cardiac amyloidosis and glycogen storage diseases 2.
- The ECG can also be used to monitor patients with HOCM and assess their response to treatment, including medical therapy and septal reduction therapy 3, 4, 5.
- In addition to resting ECG, exercise testing and Holter monitoring can also be used to evaluate patients with HOCM and assess their risk of sudden cardiac death 2.
Importance of ECG in HOCM Diagnosis and Management
The ECG is an essential tool in the diagnosis and management of patients with HOCM, and its appropriate use and interpretation can make a significant difference in various clinical settings 2.
- The ECG can be used to identify patients with HOCM who are at high risk of sudden cardiac death and may benefit from implantable cardioverter-defibrillator (ICD) therapy 3.
- The ECG can also be used to monitor patients with HOCM who are undergoing treatment, including septal reduction therapy, and assess their response to treatment 4, 5.
- Multimodality imaging, including ECG, echocardiogram, and cardiac magnetic resonance imaging (CMR), is crucial in the diagnosis and management of patients with HOCM 6.