Sleeping pills and heart failure

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.

Insomnia can increase risk of developing heart failure

Here is a study that got lots of press. Researchers studied over 54,000 Norwegians who were initially free of heart failure. The researchers asked the respondents how many times per week they have difficulty falling asleep, staying asleep, or woke unrefreshed. The results showed that in those that reported difficulty falling and staying asleep almost every night, and waking unrefreshed at least once a week, had a three fold increase in chance of developing heart failure. The researchers adjusted for factors that could affect the results, such as age, sex, marital status, education, shift work, blood pressure, cholesterol, diabetes, body mass index, physical activity, smoking, alcohol, any previous heart attack, depression and anxiety.

Now, before you panic, step back for a minute. These results support an association between insomnia and heart failure, but not that insomnia causes heart failure. Also, these patients were not examined before by sleep physicians and did not have sleep studies. Obstructive sleep apnea (OSA) could cause insomnia, and OSA is known to increase the risk of heart failure. So the insomnia reported by these study participants could be just a marker for undiagnosed OSA. This could explain the increased risk of heart failure, not the insomnia itself. And the study researchers did not adjust for OSA or other sleep related breathing disorders.

The authors theorize that if insomnia is linked to heart failure, then treating the insomnia may reduce risk of developing heart failure. I agree, as long as the cause of the insomnia is evaluated first.

Treatment of Cheyne-Stokes Respiration

There is an article in Therapeutic Advances in Respiratory Disease that reviews Cheyne-Stokes respiration and its treatment. Viewer warning, this is a technically complicated subject.

There are two main types of sleep apnea. The most common is obstructive (OSA) characterized by repetitive closure of the throat while asleep. The other is central sleep apnea CSA), where the upper airway is open, but the brain does not tell the lungs to breathe often or deep enough. One type of CSA is Cheyne-Stokes respiration (CSR) characterized by brief, repetitive periods of waxing and waning breath depths and brief, repetitive complete pauses in breathing. It is most common in neurological and heart disease.

The exact reasons of why or how patients develop CSR is unknown. Breathing during sleep is controlled by carbon dioxide levels (and oxygen to some degree). In CSR, it is theorized that the brain is over- and under-reacting to changes in CO2 in such a way that the patient breathes too deep sometimes and not at all at other times.

Treatment of CSR is more challenging than OSA. Maximizing medical treatment of the underlyinig heart or brain disease is the first step. Supplemental oxygen used during sleep can help some CSR patients. Certain medications can help because, in theory, they are respiratory stimulants, but objective data do not overwhelmingly support their use.

CPAP has been shown to be effective in some, but not all CSR patients. There was a large trial in Canada that showed that CPAP can improve cardiac function, respiratory disturbances, sympatheticoadrenal activity, and exercise performance, but NOT survival times. However, a re-analysis of the Canadian trial showed a survival benefit in those patients whose breathing disturbances were sufficiently reduced as compared to those without improvement in respiratory disturbances. Therefore, optimal suppression of respiratory disturbances is essential in CSR patients.

Bilevel positive airway pressure (BiPAP) is occasionally used in CSR patients, but there is very limited data on this mode of therapy. Adaptive servo-ventilation (ASV) is a new type of airway pressure that adapts to the patient's waxing and waning breathing patterns. It has been shown to be effective in CSR patients and studies have shown it superior to CPAP and BiPAP.

The Other Sleep Apnea?

When patients ask me about sleep apnea, most often they are referring to obstructive sleep apnea, characterized by repetitive throat collapse while asleep. There is another type of sleep apnea, central sleep apnea, where a person will stop breathing, but the throat remains open.

Central sleep apnea occurs when a person breathes too slowly or not deep enough. It can occur in the setting of brain, heart, or lung diseases. In heart failure, central sleep apnea can be a problem, and not all cardiologists are aware of it.

The symptoms of central sleep apnea can be similar to those seen in obstructive sleep apnea, such as restless sleep, daytime sleepiness or extreme fatigue, and unusual breathing patterns while asleep (usually observed by a bed partner).

Although central sleep apnea gets less attention than the more common obstructive sleep apnea, both deserve to be treated since both conditions can increase mortality rates. However, the treatment for each sleep apnea type can be different, making it important to figure out the exact type of sleep apnea that is affecting the patient.