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Relation between apex cardiogram and changes in left ventricular pressure and dimension
Insights
Apex cardiogram-echocardiography loops reveal abnormal left ventricular (LV) wall motion in heart disease patients. This method effectively detects incoordinate LV contraction, offering insights into cardiac mechanics.
Area of Science:
- Cardiology
- Biomedical Engineering
- Diagnostic Imaging
Background:
- The apex cardiogram (ACG) provides indirect information about left ventricular (LV) dynamics.
- Echocardiography allows direct measurement of LV dimensions.
- Integrating ACG with echocardiography may enhance the assessment of LV function.
Purpose of the Study:
- To investigate the relationship between apex cardiogram signals and left ventricular pressure and dimension changes.
- To evaluate the utility of combined apex cardiogram-echocardiography in detecting abnormal left ventricular contraction patterns.
Main Methods:
- Simultaneous recording of apex cardiogram, left ventricular pressure (micromanometer), and left ventricular dimensions (echocardiography).
- Analysis of ACG-derived timing relative to LV pressure upstroke and downstroke.
- Construction and analysis of apex cardiogram-echocardiography dimension loops in normal subjects and patients with various heart conditions.
Main Results:
- Apex cardiogram showed delays relative to LV pressure upstroke and downstroke in some patients.
- Normal subjects exhibited minimal LV dimensional changes synchronous with ACG.
- Patients with mitral regurgitation, aortic regurgitation, and ischemic heart disease demonstrated abnormal LV wall motion patterns during specific ACG phases.
- Apex cardiogram-echocardiography dimension loops effectively visualized these abnormalities, including incoordinate contractions.
Conclusions:
- Apex cardiogram-echocardiography dimension loops are a sensitive tool for detecting abnormal left ventricular wall motion and incoordinate contractions.
- This integrated approach offers valuable diagnostic information in patients with diverse cardiac pathologies.
- The method provides insights analogous to pressure-dimension loops for assessing cardiac mechanics.
Abstract:
The relation between the apex cardiogram and changes in left ventricular pressure measured by micromanometer, and dimension measured by echocardiography, was studied in 12 normal subjects and 64 patients with heart disease. In 12 patients, the apex cardiogram was delayed with respect to simultaneous left ventricular pressure by 17 +/- 18 ms during the upstroke and 28 +/- 16 ms during the downstroke. In the normal subjects, changes in left ventricular dimension during the upstroke and downstroke of the apex cardiogram were small, amounting to 6 +/- 5 and 21 +/- 7 per cent total excursion, respectively. In 10 patients with mitral regurgitation, there was significant inward wall movement during the upstroke and in 10 patients with aortic regurgitation, significant outward movement during the downstroke, both reflecting valvular regurgitation. In 20 patients with ischaemic heart disease and segmental abnormalities on left ventricular angiography, apex cardiogram-echo dimension relations were abnormal in all, because of inward or outward wall movement during the upstroke, increased outward movement before the 'O' point, or abnormal inward movement during the downstroke. These disturbances were displayed by constructing apex cardiogram-echo dimension loops, which appear to be a sensitive means of detecting incoordinate left ventricular contraction, analogous to those between pressure and dimension.