Preload Afterload
Preload Afterload - Related Videos
09:40
Magnetic Adjustment of Afterload in Engineered Heart Tissues
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2020
This protocol provides detailed methods describing the fabrication and implementation of a magnetics-based afterload tuning platform for engineered heart tissues.
09:32
Continuous Venous-Arterial Doppler Ultrasound During a Preload Challenge
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Cited by 3 •
2023
The Frank-Starling-Sarnoff curve is clinically important and describes the relationship between cardiac preload and output. This report illustrates a novel method of simultaneous jugular venous and carotid arterial Doppler velocimetry as transient surrogates of cardiac preload and output, respectively; this approach is enabled by wireless, wearable Doppler ultrasound.
08:49
Cardiac Loading using Passive Left Atrial Pressurization and Passive Afterload for Graft Assessment
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Cited by 7 •
2024
The protocol describes a porcine ex vivo heart perfusion system in which direct loading of the left ventricle may serve as an assessment technique for graft health while simultaneously providing a holistic evaluation of graft function. A discussion of the system design and possible assessment metrics is also provided.
08:15
Cardiac Pressure-Volume Loop Analysis Using Conductance Catheters in Mice
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Cited by 33 •
2015
Cardiac pressure-volume loop analysis is the most comprehensive way to measure cardiac function in the intact heart. We describe a technique to perform and analyze cardiac pressure volume loops, using conductance catheters.
12:07
NADH Fluorescence Imaging of Isolated Biventricular Working Rabbit Hearts
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Cited by 24 •
2012
The objective is to monitor the mitochondrial redox state of isolated hearts within the context of physiologic preload and afterload pressures. A biventricular working rabbit heart model is presented. High spatiotemporal resolution fluorescence imaging of NADH is used to monitor the mitochondrial redox state of epicardial tissue.
FAQs
The Frank–Starling mechanism links ventricular filling to contraction: when venous return raises end-diastolic filling, greater ventricular wall stretch can influence the force of contraction and stroke volume. This relationship explains why preload changes can alter cardiac output, making filling conditions central to interpreting cardiovascular drug effects.
A higher afterload requires the ventricle to overcome greater resistance before ejecting blood. Arterial pressure and vascular tone contribute to this resistance, so changes in either can affect ejection, stroke volume, and cardiac output. The resulting workload change helps explain why vascular effects are important when evaluating cardiovascular pharmacology.
Preload-reducing interventions primarily change ventricular filling conditions, whereas afterload-reducing interventions lower the resistance faced during ejection. Diuretics and venodilators are associated with reducing preload, while arterial vasodilators lower afterload. Distinguishing these effects helps connect a drug’s vascular or fluid-related action with its influence on cardiac performance.
Pressure–volume relationships provide a framework for examining how altered filling and ejection conditions affect ventricular function. Preload changes modify the conditions present before contraction, while afterload changes influence the resistance encountered during ejection. Considering both variables helps interpret associated changes in ventricular workload, stroke volume, and cardiac output.
Preload may be targeted when the therapeutic goal is to modify ventricular filling conditions, particularly in disorders involving impaired cardiac function. Diuretics and venodilators are the relevant drug approaches identified here. Their use connects changes in fluid return or venous effects with management of heart failure and related cardiovascular problems.
Arterial vasodilators lower afterload by reducing the resistance the ventricle must overcome during ejection. This action can affect ventricular workload, stroke volume, and cardiac output, while also addressing elevated vascular pressure. Consequently, afterload reduction provides a pharmacological basis for using these agents in hypertension and other disorders of cardiac function.