Patients with heart failure are at increased risk of having sleep difficulties. Sleep-related breathing difficulties like sleep apnea are also more common in heart failure patients. Here is a study that looked at sleeping pills and heart failure patients. Specifically, the researchers investigated the relationships between drugs prescribed at hospital discharge, going back into the hospital, and cardiovascular events in heart failure patients.
The results showed that sleeping pills increase the risk of cardiovascular events in heart failure patients by 8-fold. The type of sleeping pills that were most risky were the benzodiazepines like valium. At the end of the article, the researchers speculate that benzodiazepine sleep aids could reduce cardiac function or cause respiratory depression, and this could worsen any underlying sleep-related breathing disorders. The latter is certainly possible and underscores the importance of heart failure patients getting evaluated for sleep apnea. Prior to prescribing sleep aids, it's best to rule out sleep-related breathing disorders. If sleep apnea is present, that needs to be treated, rather than just giving sleep aids.