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[Regional left ventricular diastolic function in hypertrophic cardiomyopathy: application of "sector analysis" to ECG
Y Ishida1, N Matsubara, A Tani
1First Department of Medicine, Osaka University School of Medicine.
Insights
This study introduces a computer-assisted sector analysis for evaluating diastolic filling in hypertrophic cardiomyopathy (HCM). The method reveals diastolic asynchrony in hypertrophied regions, impacting left ventricular filling rates.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Context:
- Hypertrophic cardiomyopathy (HCM) is a complex condition affecting heart muscle structure and function.
- Understanding regional left ventricular (LV) diastolic filling patterns is crucial for diagnosing and managing HCM.
- Current methods may not fully capture the regional mechanical differences in HCM patients.
Purpose:
- To develop and validate a computer-assisted "sector analysis" method using ECG-gated radionuclide ventriculography.
- To estimate regional left ventricular (LV) diastolic filling patterns, including regional peak filling rate (rPFR) and time to rPFR (rTPFR).
- To assess LV diastolic asynchrony and atrial contribution to filling in patients with HCM.
Summary:
- A novel computer-assisted sector analysis was applied to radionuclide ventriculography in 14 HCM patients.
- The analysis quantified regional diastolic filling parameters and identified delayed filling (rTPFR) in hypertrophied areas.
- Diastolic asynchrony correlated with reduced global LV early filling, and increased atrial contribution was noted in hypertrophied regions.
Impact:
- This method provides valuable insights into regional diastolic LV mechanics in HCM.
- It highlights the role of diastolic asynchrony and atrial function in the pathophysiology of HCM.
- The findings can aid in refining diagnostic and therapeutic strategies for HCM.
Abstract:
To estimate regional left ventricular (LV) diastolic filling patterns in hypertrophic cardiomyopathy (HCM), a computer-assisted method by applying "sector analysis" to ECG forward and reverse gated radionuclide ventriculography was developed. Fourteen patients with HCM (four with localized septal hypertrophy, seven with apical hypertrophy and three with septal and apical hypertrophy according to echocardiography) were observed at rest. After establishing serial 20 msec imaged frames, the LV region of interest was subdivided into eight sectors radiating from the geometric center. A time-activity curve was generated for each sector and was fitted by third-order harmonics of the Fourier series. From each fitted curve, the regional peak filling rate (rPFR) and the time of rPFR (rTPFR) in the forward gating method and regional atrial contribution to filling (rAC/FV) in the reverse gating method were calculated. The coefficient of variance of rTPFR was used as an index of LV diastolic asynchrony. In HCM, a prominent delay of rTPFR was observed in the hypertrophied regions. The coefficient of variance of rTPFR correlated inversely with global LVPFR (r = -0.62, p less than 0.05), indicating that diastolic asynchrony is one of the determinants of the LV early filling rate. Regional AC/FV was augmented in the hypertrophied regions, indicating the important role of atrial systolic LV filling for slowed early filling. Thus, this new method provides valuable information concerning regional diastolic LV wall mechanics in HCM.