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Noninvasive indexes of left atrial diastolic function in hypertrophic cardiomyopathy
P S Dardas1, G S Filippatos, D D Tsikaderis
1Cardiac Unit, Papworth Hospital, Cambridge, UK.
Insights
Left atrial function is impaired in hypertrophic cardiomyopathy, not solely due to left ventricular issues. This suggests hypertrophic cardiomyopathy affects the entire heart muscle, impacting diastolic function.
Area of Science:
- Cardiology
- Cardiac Physiology
- Echocardiography
Background:
- Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy.
- Left ventricular diastolic dysfunction is common in HCM.
- The role of left atrial function in HCM remains incompletely understood.
Purpose of the Study:
- To noninvasively assess left atrial diastolic function in patients with HCM.
- To investigate the relationship between left atrial diastolic function and impaired left ventricular filling in HCM.
- To compare left atrial and left ventricular diastolic function in HCM versus secondary left ventricular hypertrophy and controls.
Main Methods:
- Echocardiography was used to study 34 patients with HCM, 26 with secondary left ventricular hypertrophy, and 21 controls.
- Left atrial diastolic function was assessed using pulmonary venous flow systolic wave indexes: acceleration time, deceleration time, and EF slope.
- Left ventricular diastolic function was evaluated using transmitral Doppler parameters.
Main Results:
- Patients with HCM showed significantly reduced acceleration time, prolonged deceleration time, and reduced EF slope of the pulmonary venous flow systolic wave.
- These left atrial diastolic function indexes were abnormal in HCM but similar in secondary left ventricular hypertrophy and control groups.
- No significant correlation was found between left atrial and left ventricular diastolic function indexes in HCM patients.
Conclusions:
- Echocardiographic indexes of left atrial relaxation and filling are abnormal in HCM, independent of left ventricular diastolic dysfunction.
- These abnormalities suggest HCM is a global cardiac myopathic disease affecting the entire heart muscle.
- Left atrial dysfunction in HCM is not solely attributable to left ventricular hypertrophy or outflow tract obstruction.
Objectives:
Our goal was to noninvasively assess left atrial diastolic function and its relation to the impaired left ventricular filling in patients with hypertrophic cardiomyopathy.
Methods And Results:
We studied 34 patients with hypertrophic cardiomyopathy, 26 patients with secondary forms of left ventricular hypertrophy (aortic stenosis, fixed subaortic stenosis, hypertension), and 21 control subjects. Left atrial diastolic function was assessed by measuring acceleration time (SAT), deceleration time (SDT), and the EF (mean deceleration rate) slope of the pulmonary venous flow systolic wave (SW). Left ventricular diastolic function assessed by transmitral Doppler included peak early left ventricular and peak atrial filling velocities, the ratio of early-to-late peak velocities, isovolumic relaxation time, deceleration time, and EF slope. In patients with hypertrophic cardiomyopathy, acceleration time was significantly reduced (P<.05), deceleration time was significantly prolonged (P<.0001), and EF slope was significantly reduced (P<.01). These indexes were similar among the other two groups. No statistically significant difference existed between the subgroups of hypertrophic cardiomyopathy in the above indexes. Patients with hypertrophic cardiomyopathy and secondary forms of left ventricular hypertrophy had evidence of left ventricular diastolic dysfunction. In patients with hypertrophic cardiomyopathy, no correlation existed between left atrial and left ventricular diastolic function indexes (r = -0.26 to 0.33).
Conclusions:
Echocardiographic indexes of left atrial relaxation and filling are abnormal in patients with hypertrophic cardiomyopathy but not in secondary forms of left ventricular hypertrophy. These indexes are abnormal in all forms of hypertrophic cardiomyopathy irrespective of left ventricular outflow tract obstruction and distribution of hypertrophy; they are not solely attributable to left ventricular diastolic dysfunction. The above may imply that hypertrophic cardiomyopathy is a cardiac myopathic disease that involves the heart muscle as a whole, irrespective of distribution of hypertrophy and obstruction.