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Left ventricular contractile function in aortic stenosis evaluated by isovolumic and ejection phase indexes
Insights
For detecting abnormal left ventricular function in aortic stenosis, combining isovolumic and ejection phase indexes is most reliable. Neither index type alone is superior for assessing contractile function in this condition.
Area of Science:
- Cardiology
- Biomedical Engineering
- Physiology
Background:
- Assessing left ventricular (LV) contractile function is crucial in conditions like chronic pressure overload.
- Aortic stenosis commonly causes chronic LV pressure overload, necessitating accurate functional assessment.
- Existing methods rely on isovolumic and ejection phase indexes, but their comparative utility is debated.
Purpose of the Study:
- To reappraise the usefulness of isovolumic versus ejection phase indexes for detecting abnormal LV contractile function.
- To evaluate index utility in patients with chronic LV pressure overload due to aortic stenosis.
- To determine the most reliable method for assessing basal LV contractile function in this patient group.
Main Methods:
- Studied 41 patients with pure or predominant aortic stenosis.
- Measured LV pressure using micromanometry.
- Acquired single-plane LV cineangiograms (RAO and A-P views).
- Calculated isovolumic indexes: peak measured velocity of shortening of contractile elements (Vpm) and Vmax.
- Calculated ejection phase indexes: mean velocity of circumferential fiber shortening (VCF) and mean normalized systolic ejection rate (MNSER).
Main Results:
- Depressed Vpm in 39%, Vmax in 42%, VCF in 29%, and MNSER in 34% of patients.
- Combined indexes identified abnormal function in 59% of patients.
- Isovolumic and ejection phase indexes agreed in 65% (26/41) of patients.
- Discordant results between index types were observed in 37% (15/41) of patients.
- Left ventricular end-diastolic pressure showed inconsistent correlation with contractile function abnormalities.
Conclusions:
- Neither isovolumic nor ejection phase indexes are superior in sensitivity for assessing LV contractile function in chronic aortic stenosis.
- Combining both isovolumic and ejection phase indexes offers the most reliable assessment of basal LV contractile function.
- Accurate assessment of LV function in pressure overload requires a comprehensive approach using multiple index types.
Abstract:
This study is to reappraise the usefulness of isovolumic as compared to ejection phase indexes for detecting abnormal left ventricular contractile function patients with a common hemodynamic abnormality, namely, chronic left ventricular pressure overload. In 41 subjects with pure or predominant aortic stenosis left ventricular pressure measurements were performed by micromanometry. Single-plane left ventricular cineangiograms were carried out in the right anterior oblique (RAO) and the A-P position. The isovolumic contractile indexes we used in this study were peak measured velocity of shortening of the contractile elements (Vpm) and Vmax obtained from linear extrapolation of total pressure-velocity curves. The end-diastolic and end-systolic RAO cineventriculograms served for the calculation of the ejection phase parameters mean velocity of circumferential fiber shortening (VCF) and mean normalized systolic ejection rate (MNSER). Of the 41 patients, Vpm was depressed in 16 (39 per cent), Vmax in 17 (42 per cent), VCF in 12 (29 per cent), and MNSER in 14 (34 per cent). When the isovolumic and the ejection phase parameters were combined, 24 patients (59 per cent) were found to have at least one of the four contractile indexes below normal. In 26 of the 41 patients the isovolumic and the ejection phase indexes provided the same conclusions as to normality of left ventricular function. In contrast, 15 patients showed discordant isovolumic and ejection phase indexes. An increased left ventricular end-diastolic pressure was only inconsistently related to an abnormal left ventricular function because in 7 of 28 patients with an end-diastolic pressure above 14 mm. Hg all contractile indexes were normal. Furthermore, a normal end-diastolic pressure was present in three of 24 patients with depressed myocardial function. It is concluded that in chronic left ventricular pressure overload from aortic stenosis neither the isovolumic nor the ejection phase indexes are superior in sensitivity for assessing contractile function. In this clinical setting the combination of both types of indexes appears to be the most reliable way for identifying patients with depressed contractile function of theleft ventricle in the basal state.