Sleep apnea's toll on the heart

January 4, 2012 · No Comments

Health professionals commonly warn about the long-term effects of sleep apnea on patients’ health, sometimes with great result, but more often than not, patients fail to fully understand the risks involved and the major health changes they are about to face. This blog post is part of a series on disease prevention and management we will be covering in the weeks ahead to help individuals better assess their sleep health.

I may have sleep apnea… so what?

How would you feel if you had to hold your breath for 10 to 30 seconds every few minutes during daytime for 6-8 hours? Not only would it be unpleasant, but you might get very tired from undergoing such a repetitive asphyxia…. After one day of this regimen, you may very well want to stop that game, knowing it is bad for your heart… and your brain (if any is left from it!).

This is exactly what you should remind yourself if you have untreated sleep apnea. Years of recurrent hypoxia during sleep can cause or worsen high blood pressure, elevate blood lipid levels, contribute to insulin resistance and diabetes, and markedly increase the risk for heart attack and stroke. Sleep apnea may also produce ventricular hypertrophy (heart enlargement) and diastolic dysfunction (inadequate filling of the ventricle) of the heart, which can eventually progress into heart failure. 

Not only may sleep apnea be a cause of congestive heart failure, but the presence of congestive heart failure may also trigger or exacerbate sleep-disordered breathing. Below are a few recommendations for you to keep in mind… and act on!

Sleep apnea may lead to congestive heart failure… if you don’t address it!

Individuals with sleep apnea have a two-fold risk of developing congestive heart failure (CHF). Contributing risk factors for sleep apnea include age, obesity, large neck circumference, craniofacial abnormalities such as a small lower jaw, sleeping on your back, or the presence of cardiovascular disease. Current research suggests that Obstructive Sleep  Apnea (OSA) may lead to CHF independent of age, obesity, or other such common risk factors. Patients with OSA typically experience many repetitive obstructive breathing events during sleep exceeding 30 to 60 times per hour, leading to disrupted nocturnal sleep and a recurrent hypoxia. So if you experience daytime sleepiness or if any of those risk factors are familiar, get help!

Congestive heart failure may cause central sleep apnea… if you don’t address it!

Between 50% to 70% of patients with congestive heart failure develop a sleep-related breathing disorder. They are at a higher risk of dying prematurely from these breathing stoppages during sleep as their heart may not function properly when exposed to repetitive low levels of oxygen in the blood. Of the patients with CHF who later develop breathing disruptions during sleep, only a minority of CHF patients develop breathing stoppages from a mechanical obstruction to the airway as seen in OSA. Instead, the majority of them develop central sleep apnea, a condition that occurs when the brain fails to transmit the proper signals to breathe. CHF patients with central sleep apnea typically experience long apneas, which can last up to 40 seconds and have arousals only several breaths after the resumption of normal breathing. 

A potential problem of the central apneas during sleep is the negative impact it may have in CHF patients. The hypoxia may worsen the blood pressure, promote ischemia and worsen existing heart failure by causing irregular heart beats (arrhythmia). Patients are often tired or sleepy from poor quality of sleep. A recent study shows that hypoxia in CHF patients contributes to an overabundance of free fatty acids, which can lead to insulin resistance, vascular dysfunction, hyperlipidemia and dysfunction of the heart muscle. 

Get treated! 

It is essential for individuals with sleep apnea to be evaluated and treated as soon as possible to prevent congestive heart failure from developing or worsening. The gold standard of treatment consists of using Continuous Positive Airway Pressure (CPAP) to open the airway during sleep, which consequently decreases the apneas, improves blood pressure, augments cardiac output, and reduces myocardial oxygen consumption, as well as other cardiovascular complications such as atrial fibrillation. Patients who cannot tolerate CPAP may benefit from an adaptive servoventilation device which performs a breath-to-breath analysis of the patient's respiratory needs, automatically adjusts the amount of airflow it delivers and is especially helpful when central sleep apnea is present. Other treatments include weight loss and oral surgery for patients whose apnea is caused by an anatomical obstruction. Finally, oral appliances are generally not recommended in patients with heart failure, especially for patients with severe sleep apnea.



Tags: congestive heart failure · patients · sleep apnea

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