Myocardial Contractility
Myocardial Contractility - Related Videos
11:50
High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart
0 Views •
Cited by 9 •
2010
High frequency Doppler ultrasound is a novel technology for assessing regional myocardial function. This work presents first evidence demonstrating applicability of this versatile imaging platform for the repeated measure of myocardial strain, dp/dt, and mitral regurgitation in the ischemia-reperfused (IR) murine heart.
02:15
The Contractile Ring
0 Views •
2023
Contractile rings are composed of microfilaments and are responsible for separating the daughter cells during cytokinesis. Contractile ring assembly proceeds along with other cell cycle events; however, very few mechanistic details are known about the timing and coordination of the contractile rings with the cell cycle. A small GTPase, RhoA, controls the function and assembly of the contractile ring. RhoA belongs to the Ras superfamily of proteins. The activation of formins by RhoA promotes...
02:15
The Contractile Ring
0 Views •
2021
Contractile rings are composed of microfilaments and are responsible for separating the daughter cells during cytokinesis. Contractile ring assembly proceeds along with other cell cycle events; however, very few mechanistic details are known about the timing and coordination of the contractile rings with the cell cycle. A small GTPase, RhoA, controls the function and assembly of the contractile ring. RhoA belongs to the Ras superfamily of proteins. The activation of formins by RhoA promotes...
08:08
Measurement of Cytosolic Ca2+ in Isolated Contractile Lymphatics
0 Views •
Cited by 24 •
2011
We introduce an approach to evaluate the cytosolic Ca2+ concentration in isolated lymphatics to study Ca2+-dependent and Ca2+-sensitizing mechanisms of lymphatic smooth muscle contraction.
09:49
Procedures for Rat in situ Skeletal Muscle Contractile Properties
0 Views •
Cited by 18 •
2011
This video demonstrates the surgical preparation and procedures needed to study the contractile responses of the rat medial gastrocnemius muscle preparation in situ. This preparation allows measurement of skeletal muscle contractile properties under physiological conditions. The animal is anesthetized and the muscle is separated from surrounding tissue at its distal end. The Achilles tendon is attached to a force transducer, allowing measurement of the muscle’s contractile response at 37...
FAQs
Calcium regulation links electrical activation to mechanical force. Calcium enters cardiomyocytes through voltage-gated channels, which triggers additional calcium release from the sarcoplasmic reticulum, an intracellular calcium store. The increased calcium availability enables actin–myosin cross-bridge cycling, allowing cardiac muscle to generate force and shorten. Disruption at any stage can alter ventricular performance.
Sympathetic stimulation and circulating catecholamines enhance contractility by increasing calcium entry into cardiomyocytes and making more calcium available for contraction. This strengthens actin–myosin cross-bridge cycling during systole. The mechanism explains why neurohumoral activation can change cardiac force generation and why medications that influence these pathways may affect ventricular function.
Contractility represents the force-generating state of the cardiac muscle itself, whereas ventricular filling and arterial pressure describe other conditions affecting cardiac performance. Keeping these factors conceptually separate helps clinicians interpret whether altered ventricular function reflects reduced muscle force or changes in loading conditions. This distinction is important when evaluating heart failure and shock.
Ischemia, myocardial injury, and some medications can reduce the heart muscle’s ability to generate force. Ischemia may interfere with the cellular processes that support contraction, while injury can impair the myocardium more directly. Medication effects vary, but their potential influence matters when interpreting ventricular function or considering causes of deterioration in heart failure and shock.
Assessment of contractility helps clinicians interpret how effectively the myocardium generates force during systole. It provides context for understanding ventricular dysfunction rather than viewing cardiac performance only through filling or arterial pressure. In medicine, this information contributes to evaluation of heart failure and shock, where impaired force generation may influence treatment decisions.
Inotropic drugs and other cardiovascular interventions may be considered when contractile performance is clinically important, particularly in the setting of heart failure or shock. Their relevance comes from the need to influence cardiovascular function when the myocardium is not generating adequate force. Understanding calcium-dependent contraction and factors that suppress it helps frame these treatment decisions.