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Study on the genesis of giant negative T wave in apical hypertrophic cardiomyopathy using a three-dimensional
H Tsunakawa1, D Wei, S Mashima
1Division of Cardiology, Showa University Fujigaoka Hospital, Yokohama, Japan.
Insights
This study used a 3D computer model to simulate electrocardiogram (ECG) abnormalities in apical hypertrophic cardiomyopathy. The model successfully replicated giant negative T waves by incorporating specific hypertrophic cell properties at the left ventricular apex.
Area of Science:
- Cardiology
- Computational Biology
- Biophysics
Background:
- Apical hypertrophic cardiomyopathy (AHCM) presents with distinctive electrocardiogram (ECG) findings, including spade-like left ventricular cavities, giant negative T waves, and tall R waves.
- The underlying mechanisms driving these specific ECG abnormalities in AHCM remain incompletely understood.
Purpose of the Study:
- To elucidate the electrophysiological mechanisms responsible for the characteristic ECG abnormalities observed in apical hypertrophic cardiomyopathy.
- To validate a novel three-dimensional (3D) computational model for simulating cardiac electrical activity in disease states.
Main Methods:
- Development of a 3D computer model simulating ventricular depolarization and repolarization.
- Construction of an AHCM model by augmenting the left ventricular apex with additional cellular units.
- Calculation of surface ECGs by varying action potential durations and proportions of hypertrophic cells in the apical segment.
Main Results:
- The computational model successfully simulated normal QRST waveforms and ECG changes associated with certain cardiac conditions.
- A simulated ECG exhibiting a -1.45 mV negative T wave in lead V4, consistent with clinical observations in AHCM, was achieved.
- This specific ECG pattern was reproduced by modeling diffusely distributed hypertrophic cells at the apex with uniform, prolonged action potential durations.
Conclusions:
- The study suggests that diffuse distribution and uniform, long action potential durations of hypertrophic cells in the apical region are key factors contributing to the distinctive ECG abnormalities in AHCM.
- The developed 3D computational model serves as a valuable tool for investigating the electrophysiological basis of cardiac diseases.
Abstract:
Apical hypertrophic cardiomyopathy is characterized by a spade-like left ventricular cavity and by both giant negative T waves and tall R waves in the electrocardiogram. However, the mechanisms of these ECG abnormalities have not been satisfactorily clarified. We have recently developed a three-dimensional computer model of ventricular depolarization and repolarization processes. This model has successfully simulated normal QRST waves and changes characterizing some abnormal conditions. A model of apical hypertrophic cardiomyopathy was constructed by adding model units to the endocardium of the left ventricular apex. The surface ECG was then calculated by assuming different gradients of action potential durations and different proportions of the hypertrophic cells in the apical segment. A negative T wave of -1.45 mV in lead V4, similar to the clinically reported ECG, was obtained by assuming: (1) diffusely distributed hypertrophic cells at the apex and (2) uniform, long action potential durations of hypertrophic cells. It is suggested that these properties may account for the distinctive ECG abnormalities in apical hypertrophic cardiomyopathy.