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Assessment of left ventricular function by synchronous echocardiography and apex cardiography
Insights
This study reveals how plotting apex cardiography against left ventricular dimension can identify heart disease. This method detects abnormal ventricular function during isovolumic phases, aiding early diagnosis.
Area of Science:
- Cardiology
- Biomedical Engineering
- Diagnostic Imaging
Background:
- Left ventricular (LV) function is crucial for cardiovascular health.
- Assessing LV dynamics traditionally relies on echocardiography.
- Novel methods are needed for early detection of cardiac abnormalities.
Purpose of the Study:
- To investigate the relationship between LV dimension and apex cardiography.
- To identify characteristic alterations in cardiac function during isovolumic phases.
- To establish a method for quantifying ventricular abnormalities.
Main Methods:
- Utilized M-mode echocardiography and simultaneous apex cardiography.
- Generated a loop by plotting apex cardiogram (ventricular wall stress indicator) against LV dimension.
- Analyzed loop patterns and differential downstroke of the apex cardiogram.
Main Results:
- Abnormal LV function manifested as characteristic alterations in the apex cardiogram-LV dimension loop.
- 25% of heart disease patients showed abnormal LV dimension changes during isovolumic contraction and relaxation.
- Differential analysis of the apex cardiogram downstroke identified 60% of heart disease patients outside the normal range.
Conclusions:
- The combined use of M-mode echocardiography and apex cardiography effectively reveals abnormal ventricular responses to pressure changes.
- This technique quantifies functional abnormalities during isovolumic phases.
- It enables early detection of impaired myocardial behavior, potentially before conventional ultrasound shows changes.
Abstract:
The relationship between left ventricular dimension measured using M-mode echocardiography and simultaneous apex cardiography has been studied in 69 normal subjects (2 groups) and 159 patients with heart disease (6 groups). A loop was formed by plotting the apex cardiogram, which is related to ventricular wall stress, against ventricular dimension. Abnormalities in ventricular function due to shape or volume changes in the isovolumic phases of the cardiac cycle produced characteristic alterations in the loop pattern. These changes were measured and the results for different groups compared. Normal subjects were divided into two age groups (13-38, 40-78) and no significant differences were found between them. In the heart-disease, patients, 25% had an abnormal decrease in dimension during isovolumic contraction and 25% had an abnormal increase during isovolumic relaxation. When the downstroke of the apex cardiogram was differentially analysed, it was possible to show that 60% of heart-disease patients lay outside the normal range. By using these techniques it is possible (a) to show abnormal ventricular response to pressure changes during the isovolumic periods, (b) to quantify the abnormality and, (c) to detect early abnormal muscle behaviour before it becomes visible on conventional ultrasound recordings.