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Clinical analysis of hypertrophic cardiomyopathy which evolved into dilated phase during long-term follow-up
1Third Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
Insights
Hypertrophic cardiomyopathy (HCM) progressing to dilated phase HCM shows early decreases in ejection fraction and increases in ventricular dimension. This progression is linked to higher ventricular tachycardia risk and poor prognosis in HCM patients.
Area of Science:
- Cardiology
- Internal Medicine
Background:
- Hypertrophic cardiomyopathy (HCM) is a complex cardiac condition.
- Understanding its progression to a dilated phase is crucial for patient management.
Purpose of the Study:
- To analyze the incidence, clinical features, and prognosis of patients with HCM that progresses to dilated-phase HCM.
- To identify early indicators and outcomes associated with this transition.
Main Methods:
- Retrospective analysis of medical records from 43 HCM patients followed for at least 10 years.
- Patients were categorized into two groups: those who developed dilated-phase HCM (Group A) and those who did not (Group B).
- Echocardiography was used to define dilated-phase HCM (left ventricular end-diastolic dimension ≥ 55 mm, left ventricular ejection fraction < 50%).
Main Results:
- 10 patients (23.3%) progressed to dilated-phase HCM over a mean follow-up of 16.7 years.
- Dilated-phase HCM was associated with significantly higher incidence of ventricular tachycardia (70.0% vs 15.2%).
- Patients progressing to dilated-phase HCM experienced early decreases in left ventricular ejection fraction and increases in left ventricular end-diastolic dimension, leading to a poorer prognosis with higher cardiac death rates (50.0% vs 6.1%).
Conclusions:
- Dilated-phase HCM is characterized by early adverse changes in left ventricular dimensions and function.
- Progression to dilated-phase HCM significantly increases the risk of ventricular tachycardia and cardiac mortality.
- Early identification of these changes is vital for predicting prognosis in HCM patients.
Abstract:
The aim of the present study was to analyze the incidence, clinical features and prognosis of patients with hypertrophic cardiomyopathy (HCM) which evolved into dilated phase HCM. The medical records of 43 patients with HCM followed up for at least 10 years were analyzed retrospectively. The patients were divided into two groups: group A consisting of patients with dilated-phase HCM defined by a left ventricular end diastolic dimension (LVDD) of 55 mm or more and a left ventricular ejection fraction (LVEF) of less than 50% obtained by echocardiography, and group B, consisting of patients with HCM that did not evolve into dilated phase HCM. During the mean follow-up of 16.7 years, 10 patients (23.3%) evolved into dilated phase HCM (group A) while the remaining 33 patients (76.7%) did not (group B). Ventricular tachycardia (VT) occurred in 7 of the 10 patients (70.0%) in group A and in 5 of the 33 patients (15.2%) in group B (p < 0.001). An increase in LVDD and decreases in LVEF and SV1 + RV5 in the electrocardiogram were observed during the early phase of the follow-up period in group A, while these changes were gradual in group B. Cardiac death occurred in 5 (50.0%) of the 10 patients in group A and in 2 (6.1%) of the 33 patients in group B (p < 0.001). In conclusion, dilated-phase HCM is characterized by decreases in LVEF and SV + RV5 and an increase in LVDD during the early phase of follow-up period, and is associated with an increased incidence of VT and a poor prognosis.