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Predictors of sudden cardiac death in hypertrophic cardiomyopathy
1The Department of Internal Medicine III, The Kurume University Medical Center, Japan.
Insights
Sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HC) patients is predicted by reduced systolic blood pressure response during exercise and elevated resting left ventricular outflow tract pressure gradient. These factors help identify at-risk individuals.
Area of Science:
- Cardiology
- Clinical Medicine
- Sudden Cardiac Death Research
Background:
- Hypertrophic cardiomyopathy (HC) is a significant cause of sudden cardiac death (SCD).
- Previous research on SCD risk factors in HC, including clinical, electrocardiographic, and hemodynamic variables, has yielded inconsistent results.
- Identifying reliable predictors of SCD in HC patients is crucial for risk stratification and management.
Purpose of the Study:
- To investigate independent predictors of SCD in a large cohort of HC patients.
- To examine the relationship between various clinical, electrocardiographic, echocardiographic, hemodynamic, and exercise test findings and SCD.
- To differentiate predictors for exercise-related versus exercise-unrelated SCD.
Main Methods:
- A multivariate analysis was performed on data from 309 HC patients diagnosed between 1971 and 1994.
- Long-term follow-up averaged 9.4 years, during which SCD events were recorded.
- Variables analyzed included clinical, electrocardiographic, echocardiographic, hemodynamic, and exercise test parameters.
Main Results:
- SCD occurred in 28 patients.
- Independent predictors of SCD were a smaller difference between peak and rest systolic blood pressure during exercise testing (p=0.006) and a higher resting left ventricular outflow tract pressure gradient (p=0.003).
- Patients experiencing exercise-related SCD were younger and showed smaller systolic blood pressure increases during exercise compared to older patients with exercise-unrelated SCD who had higher outflow tract gradients.
Conclusions:
- Reduced systolic blood pressure response during exercise and elevated resting left ventricular outflow tract pressure gradient are significant independent predictors of SCD in HC.
- These findings offer valuable insights for risk stratification in HC patients.
- Understanding the distinct predictors for exercise-related and exercise-unrelated SCD can inform targeted preventive strategies.
Abstract:
Patients with hypertrophic cardiomyopathy (HC) die suddenly. Proposed risk factors for sudden cardiac death (SCD) in HC are youth, a family history of SCD, syncope, and ventricular tachycardia. Hemodynamic variables have not convincingly proved to be risk factors for SCD. Therefore, this study was designed to examine predictors of SCD in a large number of patients with HC during long-term follow-up periods. The relation of studied variables (clinical, electrocardiographic, echocardiographic, hemodynamic, and exercise test findings) to SCD in 309 patients with HC who were initially diagnosed during 1971 through 1994 (mean follow-up 9.4 years) was examined by multivariate analysis. SCD occurred in 28 patients. Independent predictors of SCD were a smaller difference between peak and rest systolic blood pressure during exercise testing (p=0.006), and higher left ventricular outflow tract pressure gradient at rest (p=0.003). Exercise-related SCD occurred in 8 patients and exercise-unrelated SCD in 20 patients (mean age 28 vs 47 years, p <0.05). Thus, patients of exercise-related SCD were younger and had smaller increases in systolic blood pressure during exercise testing, whereas patients with exercise-unrelated SCD were older and had higher left ventricular outflow tract pressure gradient.