A left lateral body position increases pulmonary vein stress in healthy humans

[aliml]

Pulmonary vein (PV) stretch is proarrhythmic for atrial fibrillation (AF). AF patients often report that a left lateral (LL) body position can trigger arrhythmia symptoms. Because the PV myocardium is thought to trigger AF, we hypothesized that the LL compared to the supine body position increases PV wall stress. Functional cardiac magnetic resonance imaging was performed in supine and LL recumbent body position in awake condition in healthy human volunteers (n = 20). Following a change from supine to LL position, the heart moved in an anterior-LL direction in the thorax. The right superior PV diameter was increased by 19% and left atrial (LA) volume was larger by 17% in LL than supine position, respectively. The passive LA conduit fraction (normalized difference between maximum and pre-contraction LA volume) increased by 25% in LL compared to supine position. Local wall stress in the PV regions increased in LL compared to supine position, whereas this was not the case in the LA walls. In conclusion, a left lateral body position increases PV myocardial stress during the atrial relaxation phase of healthy volunteers. These results have implications for the mechanisms of posture-triggered AF.

A left lateral body position increases pulmonary vein stress in healthy humans - PubMed

Pulmonary vein (PV) stretch is proarrhythmic for atrial fibrillation (AF). AF patients often report that a left lateral (LL) body position can trigger arrhythmia symptoms. Because the PV myocardium is thought to trigger AF, we hypothesized that the LL compared to the supine body position...

pubmed.ncbi.nlm.nih.gov

Patients with coronary artery disease (CAD) have depressed vagal modulation. Because the mortality risk from acute myocardial infarction is lower in patients with higher vagal modulation, methods that can increase vagal modulation are desirable for patients with CAD. The right lateral decubitus position has been found, in young healthy subjects, to lead to the highest vagal modulation among 3 recumbent positions using spectral heart rate variability (HRV) analysis. This study investigated which recumbent position can give rise to the highest vagal modulation in patients with severe CAD. Twenty-seven patients scheduled for coronary artery bypass graft surgery and 17 patients with angiographically normal coronary arteries were studied. Spectral HRV analysis was performed in random order on these patients in 3 recumbent positions: namely, the supine, left lateral decubitus, and right lateral decubitus positions. Normalized high-frequency power was the highest, whereas normalized low-frequency power and low/high-frequency power ratio in the right lateral decubitus position were the lowest, among the 3 recumbent positions in both groups of patients. The lower the normalized high-frequency power in the supine or left lateral decubitus position, the higher the increase in the normalized high-frequency power when the position was changed from supine or left lateral decubitus to right lateral decubitus in patients with severe CAD. Right lateral decubitus position can lead to the highest vagal modulation and the lowest sympathetic modulation among the 3 recumbent positions in patients with severe CAD. Therefore, the right lateral decubitus position can be used as an effective physiologic vagal enhancer in patients with severe CAD.

Comparison of three recumbent positions on vagal and sympathetic modulation using spectral heart rate variability in patients with coronary artery disease - PubMed

Patients with coronary artery disease (CAD) have depressed vagal modulation. Because the mortality risk from acute myocardial infarction is lower in patients with higher vagal modulation, methods that can increase vagal modulation are desirable for patients with CAD. The right lateral decubitus...

pubmed.ncbi.nlm.nih.gov

The aim of this study was to evaluate the effect of the supine, left lateral decubitus, and right lateral decubitus positions on autonomic nervous activity in elderly adults by using spectral analysis of heart rate variability (HRV). Forty-five adults aged 73.6 ± 5.7 years were enrolled. After lying in the supine position, all participants moved to the lateral decubitus positions in a random order and maintained the positions for 10 min, while electrocardiographic data were recorded to measure HRV. The lowest heart rate continued for 10 min when participants were in the left lateral decubitus position compared with the other two positions (p < .001), while the HRV indexes remained unchanged. The low-frequency HRV to high-frequency HRV ratio (LF/HF) for the right lateral decubitus position was significantly lower than that for the other positions. The right lateral decubitus position may attenuate sympathetic nerve activity in elderly adults.

The Cardiac Sympathetic Nerve Activity in the Elderly Is Attenuated in the Right Lateral Decubitus Position - PubMed

<span><b>Objectives:</b> The aim of this study was to evaluate the effect of the supine, left lateral decubitus, and right lateral decubitus positions on autonomic nervous activity in elderly adults by using spectral analysis of heart rate variability (HRV). <b>Method:</b> Forty-five adults aged...

pubmed.ncbi.nlm.nih.gov

This study compared the effect of 5 recumbent positions on cardiac autonomic nervous modulation in patients with coronary artery disease (CAD). Spectral heart rate variability analysis was performed on 33 CAD patients and 17 patients with patent coronary arteries in random order in 5 positions; namely, supine, right lateral decubitus, left lateral decubitus, left prone and right prone positions. In the right lateral decubitus position, the vagal modulation was the highest and the sympathetic modulation was the lowest among the 5 recumbent positions in the control group. In the CAD patients, the vagal modulation in the supine position was significantly lower than that in the other 4 positions. The lower the normalized high-frequency power (nHFP) in the supine position, the larger the percent age increase in nHFP when the position was changed from supine to another recumbent position in both CAD patients and controls. There was no significant change in the respiratory rate when the position was changed from supine to any of the other 4 positions. Right lateral decubitus position leads to the highest vagal modulation in the controls, whereas the supine position leads to the lowest vagal modulation in the CAD patients. In addition to the right lateral decubitus position, both the right and left prone positions can be used as a vagal enhancer in patients with CAD as compared with supine, especially for those patients who have severely reduced cardiac vagal modulation while supine.

Comparison of effect of 5 recumbent positions on autonomic nervous modulation in patients with coronary artery disease - PubMed

Right lateral decubitus position leads to the highest vagal modulation in the controls, whereas the supine position leads to the lowest vagal modulation in the CAD patients. In addition to the right lateral decubitus position, both the right and left prone positions can be used as a vagal...

pubmed.ncbi.nlm.nih.gov

 

[aliml]

Is Left or Right Side Sleeping Best for Your Heart?​

Most of my cardiac patients sleep better on their right side. Is right side sleeping best for your heart? In this article, I discuss the science of behind right versus left side sleeping.

Gravity and Left vs. Right Side Sleeping?​

Gravity plays a role in where the heart goes during sleep. For example, if you sleep on your left side, then gravity will pull your heart toward your chest wall. In contrast, gravity pulls the heart toward the center of the chest with right side sleepers. This subtle change in where gravity pulls your heart may affect symptoms, cardiac output, or even your heart rate.

Why Back Sleeping is Probably Bad for the Heart​

If you are carrying any extra weight, back sleeping is definitely bad for your heart. This is because when you sleep on your back, the extra weight collapses your airway (sleep apnea). And studies show that sleep apnea dramatically increases your risk of heart failure and atrial fibrillation.

Stomach sleeping is another possibility. However, as I have learned personally, stomach sleeping is a perfect recipe for neck and back issues.

4 Reasons to Sleep on Your Right Side​

1. Less Shortness of Breath​

As far back as 1937 doctors have noted that heart patients breath better sleeping on their right side. Indeed, the worse the cardiac function, the more likely people are to sleep right side down. While the reason for this isn’t entirely clear, it may have to do with a better venous return and lower pressures within the heart and lungs.

2. Better Cardiac Output​

For the same reasons as number one above, cardiac output may be better with right side sleeping. Once again, gravity pulling the heart toward the center of the chest may optimize cardiac performance.

3. Fewer Palpitations​

No one likes the sensation that their heart isn’t beating correctly. As the heart is in the center of your chest with right-sided sleeping, studies show that palpitations become much less noticeable. In contrast, when you are on your left side, the heart is pulled to the chest wall, and you may feel every irregular beat of your heart.

While many atrial fibrillation patients have noted that they have fewer arrhythmias when sleeping on the right side, I could find no studies supporting this finding. Thus, when it comes to sleeping and arrhythmias, I suggest sleeping in whatever position that seems to help.

4. Lower Heart Rate and Less Sympathetic Nervous Activity​

The sympathetic nervous system is the fight or flight response. This fight or flight response makes the heart rate and blood pressure go up.

For most of my patients, sympathetic nervous system stimulation makes their heart failure, chest pain, or arrhythmias worse. And when it comes to sleeping and sympathetic stimulation, studies show that right-sided sleeping may be better.

3 Reasons to Sleep on Your Left Side​

1. Acid Reflux Sufferers​

People suffering from acid reflux may sleep better on their left side. This is because studies show that acid reflux may be worse with right side sleeping. Thus, if your acid reflux is causing you more symptoms than your heart, you may want to consider sleeping on your left side.

2. Vagus Nerve Arrhythmias​

The vagus nerve connects the heart, brain, and gut. Because of this connection, vagus nerve activation may be an important cause of arrhythmias.

With vagus nerve stimulation, you get increased parasympathetic activity which is the exact opposite of the fight or flight response with sympathetic stimulation. Thus, to quiet your vagus nerve at night, studies suggest that you may want to try sleeping on your left side.

3. Too Slow of a Heart Rate at Night (Bradycardia)​

If you have ever worn a heart monitor, your doctor may have told you that your heart beats too slow at night. If this is the case, sleeping on your left side could stimulate a sympathetic response and increase your heart rate.

Is Left or Right Side Sleeping Best for Your Heart? - Dr. John Day, Cardiologist

http://media.blubrry.com/drjohnday/drjohnday.com/podcasts/Podcast287.mp3Podcast: Play in new window | DownloadSubscribe: RSSIs Left or Right Side Sleeping Best for Your Heart? Most of my cardiac patients sleep better on their right side. Is right side sleeping best for your heart? In this...

drjohnday.com

 

[Nokoni]

As far back as 1937 doctors have noted that heart patients breath better sleeping on their right side.

Unfortunately none of my doctors noted this for me. I did notice that I tended to sleep on my right side, and actually I tried for a while to increase my left side sleeping, merely for symmetry. But I always spontaneously reverted to right side sleeping and now, thanks to you, I know both why and that I should. Very good stuff, thanks.