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Right ventricular diastolic function in patients with hypertrophic cardiomyopathy--an invasive study
M Maeda1, T Yamakado, T Nakano
1The First Department of Internal Medicine, Mie University, Japan.
Insights
Right ventricle diastolic dysfunction is common in hypertrophic cardiomyopathy (HCM) patients, showing impaired relaxation and delayed filling. These findings highlight the need for assessing right ventricular diastolic function in HCM.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Hypertrophic cardiomyopathy (HCM) is a genetic heart disease primarily affecting the left ventricle.
- Right ventricular (RV) diastolic function in HCM is not well understood.
- Assessing RV diastolic function is crucial for a comprehensive understanding of HCM pathophysiology.
Purpose of the Study:
- To evaluate right ventricle (RV) diastolic function in patients with hypertrophic cardiomyopathy (HCM).
- To characterize abnormalities in RV relaxation and filling dynamics in HCM.
Main Methods:
- Biplane RV angiograms and RV pressures were analyzed in 19 HCM patients and 13 controls.
- Ventricular relaxation assessed by time constant of isovolumic pressure decay (T).
- Diastolic filling parameters included peak filling rate (PFR), time to PFR (TPFR), and % atrial contribution (%AF).
Main Results:
- RV isovolumic relaxation time constant (T) was significantly prolonged in HCM patients.
- Time to peak filling rate (TPFR) was significantly greater in HCM patients, indicating delayed diastolic filling.
- RV diastolic pressure-volume relations were shifted upward, suggesting decreased diastolic distensibility.
Conclusions:
- Patients with HCM exhibit impaired isovolumic relaxation of the right ventricle.
- Delayed diastolic filling and reduced diastolic distensibility are characteristic of RV dysfunction in HCM.
- These findings underscore the importance of evaluating RV diastolic function in the management of HCM.
Abstract:
To assess diastolic function of the right ventricle (RV) in patients with hypertrophic cardiomyopathy (HCM), biplane RV angiograms and RV pressures were analyzed in 19 HCM patients and in 13 normal subjects. RV and left ventricle (LV) pressures were measured using catheter-tip manometers. RV volumes were obtained from frame-by-frame tracings of angiograms. Ventricular relaxation was assessed by the time constant of isovolumic pressure decay (T). The peak filling rate (PFR) and the time to PFR (TPFR) were used as parameters of early diastolic filling, and the right atrial contribution to RV filling (%AF) was used as a parameter of late diastolic filling. The T for the RV was significantly prolonged in HCM patients. However, there was no significant correlation between the T for the RV and LV, nor did the T for the RV correlate with the RV ejection fraction or interventricular septal wall thickness. The TPFR, but not PFR, was significantly greater in HCM patients, and the %AF tended to be increased in HCM, but not significantly. The RV diastolic pressure-volume relations in the HCM patients shifted upward. In conclusion, impaired isovolumic relaxation and delayed diastolic filling and decreased diastolic distensibility are present in the RV of HCM patients.