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[Effect of chronic amiodarone therapy on left ventricular function in dilated cardiomyopathy studied by the new
1Gottsegen György Országos Kardiológiai Intézet, Budapest.
Insights
A new Doppler index effectively assesses left ventricular function in dilated cardiomyopathy. Chronic amiodarone treatment improves function by increasing diastolic filling time, not through a positive inotropic effect.
Area of Science:
- Cardiology
- Cardiac Physiology
- Echocardiography
Background:
- Systolic and diastolic dysfunction often coexist in cardiac disease.
- Combined measures of left ventricular performance may be more accurate than isolated assessments.
- A novel Doppler index, the ratio of isovolumic times plus ejection time, has been proposed for combined assessment.
Purpose of the Study:
- To evaluate the characteristics of the new Doppler index.
- To prospectively assess the impact of chronic amiodarone on left ventricular function in dilated cardiomyopathy using the new index and standard methods.
Main Methods:
- Assessed a new Doppler index (sum of isovolumic times and ejection time).
- Evaluated index features: normal ranges, heart rate dependence, and effects of mitral regurgitation and left bundle branch block.
- Prospectively studied amiodarone's effect on left ventricular function in dilated cardiomyopathy over one year.
Main Results:
- The new Doppler index has normal values within a narrow range and differentiates normal from dilated cardiomyopathy patients without overlap.
- The index is not dependent on heart rate, mitral regurgitation, or left bundle branch block.
- Amiodarone treatment in severe dilated cardiomyopathy led to decreased heart rate and the new index, with increased ejection fraction, ejection time, and relative diastolic filling time.
Conclusions:
- The new Doppler index is a simple tool for differentiating normal and abnormal left ventricular function.
- Chronic amiodarone treatment can improve left ventricular function in severe heart failure, even without arrhythmias, by increasing diastolic filling time.
Unlabelled:
Several noninvasive techniques have been used for the assessment of systolic and diastolic function. In most forms of cardiac disease however systolic and diastolic dysfunction coexist, hence a combined measure of left ventricular performance may be more reflective than their assessment alone. A recently recommended new Doppler index is supposed to be useful for this purpose. This index is the ratio of the sum of both isovolumic times and the ejection time. The objective of this study was to assess the features of the new index and then to prospectively evaluate the effect of chronic amiodarone treatment on left ventricular function using the new index and standard methods in dilated cardiomyopathy.
Results:
Normal values of the new index are within a narrow range, it separates the normal and the dilated cardiomyopathy patients without overlap, it is not heart rate dependent in either group and it is not affected by either mitral regurgitation or left bundle brunch block. The index is inversely related to the relative diastolic filling time in both groups. In severe dilated cardiomyopathy after one year amiodarone treatment there was a significant decrease of heart rate, the new Doppler index and a significant increase of ejection fraction, ejection time and relative diastolic filling time. These changes were significant already at 1 month except the new index. These results suggest that the beneficial effect of amiodarone is due to the increase of diastolic filling time rather than to a positive inotropic effect.
Conclusions:
1. The new Doppler index is simple and can be easily utilized in the differentiation of normal and abnormal left ventricular function: 2 chronic amiodarone treatment may be indicated even in the absence of arrhythmia to improve left ventricular function in severe heart failure.