Related Experiment Video
Updated: Jul 30, 2026
Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption
Published on: August 16, 2016
Lithium has no direct effect on cardiac function in the isolated, perfused rat heart
J G Linakis1, D L Savitt, J E Schuyler
1Department of Paediatrics, Hasbro Children's Hospital/Rhode Island Hospital, Providence 02903, USA. James_Linakis_PhD@brown.edu
Insights
Lithium did not directly harm rat hearts in this study. High doses caused temporary changes, but these were likely due to osmotic effects, not lithium toxicity itself.
Area of Science:
- Cardiology
- Pharmacology
- Toxicology
Background:
- Lithium is widely used for bipolar disorder.
- Concerns exist regarding its potential cardiac toxicity.
- Understanding lithium's direct cardiac effects is crucial for patient safety.
Purpose of the Study:
- To investigate the direct cardiotoxic effects of lithium on an isolated, perfused rat heart model.
- To differentiate between direct lithium toxicity and osmotic effects.
Main Methods:
- Isolated, perfused rat hearts (paced and unpaced) were used.
- Hearts were exposed to varying concentrations of lithium chloride or lithium carbonate (1, 10, 100 mM).
- Osmotic control experiments using mannitol were performed to isolate lithium's effects.
Main Results:
- Lithium at 1 and 10 mM showed no significant impact on cardiac function (pressure, heart rate, hemodynamics).
- At 100 mM, transient decreases in systolic pressure and heart rate were observed.
- These transient effects were also present in osmotic control groups, suggesting they were not directly caused by lithium.
Conclusions:
- Lithium, at the tested concentrations, does not appear to exert direct cardiotoxicity in this isolated heart model.
- Observed transient cardiac function changes at high doses are likely attributable to osmotic effects rather than inherent lithium toxicity.
Abstract:
To determine if lithium exerts direct cardiac toxicity, using an isolated, perfused rat heart model, paced and unpaced beating rat hearts were perfused with Krebs-Henseleit bicarbonate solution and left ventricular pressures were measured via a balloon-tipped catheter positioned in the left ventricle via the mitral valve. Following a stabilization period, hearts were then perfused with Krebs-Henseleit bicarbonate solution containing 1, 10, and 100 mM ionized lithium chloride or lithium carbonate in an antecedent dose-response protocol and perfused for 10 min. at each dose. To control for the possibility of osmotic effects from the high dose of lithium, an additional group was studied in which hearts were perfused with Krebs-Henseleit bicarbonate solution for an initial stabilization period, then perfused for an additional 20 min. with Krebs-Henseleit bicarbonate solution alone, and finally with Krebs-Henseleit bicarbonate solution containing mannitol (200 mOsm/l) for 10 min. Lithium did not have any effect on left ventricular peak systolic pressure, left ventricular end diastolic pressure, heart rate or coronary haemodynamics at concentrations of 1 or 10 mM. At 100 mM LiCl and Li2CO3, left ventricular peak systolic pressure decreased transiently during the first minute of lithium infusion, but recovered significant function by 10 min. Heart rate decreased significantly by 10 min. of infusion. These effects were also seen in the osmotic controls and thus do not appear to be a direct effect of lithium. At the doses tested, lithium had no direct effect on cardiac function which could not be explained by an osmotic effect.
