In the world of cardiology, many different types of arrhythmias exist. However, sinus arrhythmia is often overlooked. In many patients, this is a marker of good cardiovascular health and is asymptomatic, only found on routine EKG (Soos and McComb, 2021). Other arrhythmias, such as supraventricular tachycardia, atrial fibrillation, ventricular tachycardia, and more, can be serious and life-threatening. Sinus arrhythmias rarely present with symptoms, but if shortness of breath, edema, or chest pain are present, they can be an indicator of underlying disease such as congestive heart failure (Soos and McComb, 2021). Overall, sinus arrhythmias sound like something to be scared of, but much of the time, they are harmless!
A person’s heart rate is determined by the sinoatrial node,
or the pacemaker, of the heart, which controls the rate of contraction. The SA
node is under control of the SNS as well as the vagal nerve, the main nerve of
the PNS (Berntson, Cacioppo, and Quigley, 1993). The main type of sinus
arrhythmia is called respiratory sinus arrhythmia. Simply, in RSA, heartbeat increases
with inspiration and decreases with expiration. The R-R interval (time between
two R-waves) on an EKG varies with respiration in RSA (Yasuma & Hayano, 2004). Mechanisms of RSA are unclear, but it is assumed there are multiple components
in both central and peripheral systems that contribute (Berntson, Cacioppo, and
Quigley, 1993). We know, however, that RSA results from cardiac and pulmonary
system interactions, and having RSA may even increase efficiency of gas
exchange in the lungs (Yasuma & Hayano, 2004)!
I have personal experience with RSA. I didn't know I had it until wearing a cardiac event monitor after being misdiagnosed with SVT. Below is an instance of sinus arrhythmia. I also had episodes of PVCs, bradyarrhythmia, tachycardia, and a three-second pause (that I didn’t notice!) In my opinion, there are many ethical issues surrounding cardiology. Many patients tell stories of healthcare providers dismissing cardiac conditions as anxiety. Luckily, I have providers who believe what I feel. Ethically, I think it is best in healthcare that all cardiac symptoms are treated as such until proven otherwise. The criminal justice system plays by “innocent until proven guilty”, so I think cardiac conditions should be cardiac until proven that they aren’t. If a patient with SVT is shrugged off, they could have permanent damage done to their heart – and that damage and time will never be replaced.
Soos MP, McComb D. Sinus Arrhythmia. [Updated 2021 Sep 24].
In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022
Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537011/
Berntson, G.G., Cacioppo, J.T., & Quigley, K.S. (1993). Respiratory
sinus arrhythmia: Autonomic origins, physiological mechanisms, and
psychophysiological implications. Psychophysiology, 30, 183-196. DOI:
10.1111/j.1469-8986.1993.tb01731.x.
Yasuma, F. & Hayano, J. (2004). Respiratory sinus
arrhythmia: Why does the heartbeat synchronize with respiratory rhythm? Chest,
125(2), 683-690. https://doi.org/10.1378/chest.125.2.683
Whitney, your experience with sinus arrhythmia is super interesting! I actually was shadowing in a pediatric cardiology clinic this summer and got to watch the process behind diagnosing cardiac disorders. I learned that problems with the heart can be scary, but more often that not (although there are some exceptions), there aren't a topic of major concern. Most of the time in this office, the cardiologist would give the heart time to self correct and tried to avoid additional medical intervention. However, I do want to note that this was in children (who are more elastic that adults) and we were mostly seeing murmurs in the clinic. This still seems counter intuitive, considering the importance of the heart. I actually found this article that provides some further insight into this phenomenon. It turns out that normal heart murmurs are actually fairly common in kids 3 to 7 years old. Also, these more mild murmurs do not usually cause noticeable symptoms and, therefore, are rarely treated. Murmurs are the result of blood swooshing through certain parts of the heart.
ReplyDeleteI thought this was really interesting, since we normally associate cardiac problems with severe outcomes or maybe even death. However, reading your experience and relating it to my experience this summer has made me think otherwise. Although I do think that these outcomes vary with age and type of cardiac disorder, it's cool to think our hearts can be more resilient than we may have originally thought.
https://www.upstate.edu/heartinstitute/outpatient/conditions-treated/heart-murmur.php