Related Experiment Video

Updated: Mar 21, 2026

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
06:22

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice

Published on: September 17, 2015

15.6K

Failing Left Ventricles Have an Enhanced Post-Stimulation Potentiation Despite Their Impaired Force Frequency

Tohru Watanabe1, Takeshi Kashimura, Makoto Kodama

  • 1Department of Cardiovascular Biology and Medicine, Niigata University Graduate School of Medical and Dental Sciences.

International Heart Journal
|May 17, 2016
PubMed

Insights

Patients with heart failure have impaired force-frequency relationships (FFR). However, their post-stimulation potentiation (PSP) enhances with heart rate, suggesting refractoriness limits contractile force during tachycardia.

Area of Science:

  • Cardiology
  • Physiology

Background:

  • The force-frequency relationship (FFR), or left ventricular contractile force's response to heart rate, is impaired in systolic dysfunction.
  • Post-stimulation potentiation (PSP), the increase in contraction after a pause, is not well understood in this context.

Purpose of the Study:

  • To investigate if post-stimulation potentiation (PSP) increases in a rate-dependent manner in patients with idiopathic dilated cardiomyopathy (DCM).
  • To compare FFR and PSP between DCM patients and healthy controls.

Main Methods:

  • Assessed FFR and PSP using right atrial pacing with a micro-manometer-tipped catheter in 16 DCM patients and 6 controls.
  • Measured the increase in left ventricular dP/dtmax (LV dP/dtmax) over baseline (ΔFFR) and after pacing cessation (ΔPSP) at various pacing rates.

Main Results:

  • DCM patients had lower baseline LV dP/dtmax and significantly smaller ΔFFR compared to controls.
  • DCM patients exhibited a rate-dependent increase in PSP, with greater ΔPSP than controls at higher pacing rates.
  • Despite enhanced PSP, failing left ventricles showed limited contractile force during tachycardia.

Conclusions:

  • Impaired FFR in DCM is not due to a lack of rate-dependent PSP.
  • Refractoriness of contractile force likely underlies the impaired FFR in failing left ventricles.

More Related Videos

Preparation of Human Myocardial Tissue for Long-Term Cultivation10:58

Preparation of Human Myocardial Tissue for Long-Term Cultivation

Published on: June 2, 2022

6.0K
Author Spotlight: Investigating HR-Dependent Cardiac Function in Mouse Models Through a Novel Atrial-Pacing Approach07:49

Author Spotlight: Investigating HR-Dependent Cardiac Function in Mouse Models Through a Novel Atrial-Pacing Approach

Published on: July 21, 2023

2.1K

Related Concept Videos

Heart Failure II: Pathophysiology01:29

Heart Failure II: Pathophysiology

Systolic Heart Failure and Compensatory MechanismsSystolic heart failure (also termed HFrEF, Heart Failure with Reduced Ejection Fraction) is the most prevalent type of heart filure. It results in a decreased volume of blood being pumped from the ventricle. The aortic arch and carotid sinuses have baroreceptors that detect reduced blood pressure, triggering the sympathetic nervous system (SNS) to release epinephrine and norepinephrine. Initially, this response aims to boost heart rate and...
1.3K
Muscle Stimulation Frequency01:22

Muscle Stimulation Frequency

The contraction strength of muscles is regulated by motor neurons, which modulate the frequency of action potentials dispatched to the motor units based on the body's requirements. This process of varying the muscle stimulation frequency allows muscles to contract with a force that is precisely tailored to the needs of the moment, whether lifting a feather or a heavy box.
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...
5.0K
Regulation of Stroke Volume01:27

Regulation of Stroke Volume

The regulation of stroke volume, which is the amount of blood the heart pumps out during each heartbeat, is critical for maintaining a healthy circulatory system. Stroke volume is influenced by three main factors: preload, contractility, and afterload.
Preload refers to the degree of stretch on the heart before it contracts. It's analogous to the stretching of a rubber band; the more it's stretched, the more forcefully it snaps back. This concept is encapsulated in the Frank-Starling law of the...
5.5K
Heart Failure Drugs: Inotropic Agents01:26

Heart Failure Drugs: Inotropic Agents

Positive inotropic agents are commonly used as the first line of treatment for heart failure. One such agent is digoxin, derived from the genus Digitalis, which has been known for centuries but effectively utilized since 1785. However, these cardiac glycosides can have potentially toxic effects due to their mechanism of action, which involves inhibiting Na+/K+-ATPase and increasing contractility. Digoxin is absorbed orally and distributed in various tissues, including the CNS. It has a long...
1.8K
Imbalances in Cardiac Output01:26

Imbalances in Cardiac Output

The heart's primary function is to pump blood throughout the body, maintaining a balance between blood sent out (cardiac output) and blood returning (venous return). If this balance is disrupted, it can result in congestive heart failure (CHF), a severe condition where the heart becomes an inefficient pump, leading to inadequate blood circulation.
CHF can occur due to the failure of either side of the heart. Left-side failure leads to pulmonary congestion—the right side continues to send...
3.4K