Propionyl-L-carnitine (PLC) is a derivative of L-carnitine, which plays a role in fatty acid transport into mitochondria for energy production. The rationale for using PLC in congestive heart failure (CHF) is based on the hypothesis that improving cardiac energy metabolism may enhance heart function. Several small clinical trials and meta-analyses have examined the effects of L-carnitine derivatives, including PLC, in patients with CHF. Some studies have shown that PLC supplementation may improve exercise tolerance, reduce symptoms, and enhance left ventricular function in CHF patients. For example, a meta-analysis published in "Clinical Cardiology" (2009) concluded that L-carnitine and its derivatives have a modest benefit on cardiac function and exercise capacity in CHF, though the included studies were generally small and of variable methodological quality.

The evidence supporting PLC in CHF is limited: most studies are small, short-term, and sometimes lack rigorous controls. Guidelines from major cardiovascular societies do not currently recommend PLC as a standard therapy for CHF. The use of PLC in this context is not traditional but is based on mechanistic reasoning and limited clinical data. Therefore, while there is some scientific evidence, it is not robust, and PLC is not widely adopted in standard CHF management.