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Mechanisms of prolongation of pre-ejection period in patients with left ventricular disease
Insights
Left ventricular disease prolongs the pre-ejection period (PEPI) due to incoordinate wall motion or beta-blocker effects. Echocardiography helps differentiate these mechanisms in patients with heart conditions.
Area of Science:
- Cardiology
- Cardiac Physiology
- Diagnostic Imaging
Background:
- Left ventricular disease can lead to prolonged pre-ejection period (PEPI).
- Understanding the mechanisms behind PEPI prolongation is crucial for patient management.
- Non-invasive methods are desirable for assessing cardiac function.
Purpose of the Study:
- To investigate the mechanisms responsible for prolonged PEPI in patients with left ventricular disease.
- To differentiate between incoordinate left ventricular contraction and beta-adrenergic blockade effects on PEPI.
- To validate the use of echocardiography in separating these mechanisms.
Main Methods:
- Non-invasive study of 11 patients with congestive cardiomyopathy and 29 with coronary artery disease.
- Simultaneous recordings of carotid pulse, apex cardiogram, phonocardiogram, and echocardiogram.
- Assessment of pre-ejection period index (PEPI) and left ventricular wall motion during isovolumic contraction.
Main Results:
- Prolonged PEPI correlated with incoordinate left ventricular wall movement in untreated patients.
- A PEPI > 140 ms indicated incoordinate contraction, while PEPI < 140 ms suggested normal contraction.
- Beta-adrenergic blocking drugs prolonged PEPI beyond predictions based on wall motion alone.
Conclusions:
- Both incoordinate left ventricular contraction and negative inotropic effects (e.g., from beta-blockers) prolong PEPI.
- These mechanisms prolong PEPI through distinct pathways.
- Echocardiography-based non-invasive methods can differentiate the contributions of these mechanisms to PEPI prolongation.
Abstract:
In order to determine the mechanism underlying prolongation of the pre-ejection period in patients with left ventricular disease, 11 patients with congestive cardiomyopathy and 29 with coronary artery disease, 10 of whom were taking beta-adrenergic blocking drugs, were studied non-invasively. Recordings of carotid pulse, and apex, phono-, and echocardiogram were obtained. In the absence of treatment with beta-blocking drugs, prolongation of pre-ejection period correlated closely with incoordinate left ventricular wall movement during isovolumic contraction assessed from simultaneous apex and echocardiograms. There was no correlation between pre-ejection period index (PEPI) and end-diastolic dimension and PEPI correlated poorly with fractional shortening and peak Vcf. A PEPI of greater than 140 ms was associated with incoordinate contraction in all but one case, and of less than 140 ms with normal contraction in all. Therapeutic doses of beta-blocking drugs caused prolongation of PEPI to a greater extent than would have been predicted from wall movement during isovolumic contraction. Incoordinate left ventricular contraction and a negative inotropic effect both therefore prolong PEPI, but by different mechanisms, whose effects can be separated in individual patients using non-invasive methods based on echocardiography.