The term ‘respiratory sinus arrhythmia’ refers to a naturally-occurring variation in the heart rate that takes place during a breathing cycle. This article provides information about its clinical significance.
Arrhythmia is a condition that is characterized by an irregularity in the normal rhythm of the heartbeat. Respiratory sinus arrhythmia (RSA) is a type of arrhythmia that occurs due to the influence of breathing rhythm on the vagal nerve activity. This is a naturally-occurring cyclic variation in the heart rate that is manifested in the form of an increased heart rate with inspiration, followed by a decrease in heart rate during expiration. Since the cardiac rhythm proceeds from sinoatrial node, this naturally-occurring irregularity in the heart rhythm is medically referred to as sinus arrhythmia.
Sinoatrial node, also known as the sinus node, is a cluster of cardiac muscle fibers located in the upper section of the right atrium of the human heart. This node is also referred to as the natural pacemaker of the heart, as it performs the task of generating electrical impulses, and is the source of each heartbeat. The irregularity in the cardiac rhythm is attributed to fluctuations that take place in the vagus nerve activity.
Vagus nerve, which is a cranial nerve that extends from the brain stem to the abdomen, plays an important role in regulating the heartbeat. It slows down the force of contractions and the heart rate. During inhalation and exhalation, the cells in one of the centers of medulla oblongata, raise the parasympathetic nervous system output to the heart through this cranial nerve. This causes a cyclic variation in the heart rate. RSA is a physiological variation and is not considered to be abnormal. In fact, it is the dampening of this normal sinus rhythm which is indicative of heart problems.
Normal sinus arrhythmia is more pronounced in children and young adults. Even people whose heart is in a good condition might also have a pronounced sinus rhythm. The dampening of RSA could be associated with stress or other medical conditions. Individuals who have been experiencing fluctuations in the heart rate must consult a cardiologist.
Diagnosis and Treatment
RSA is measured with the help of an electrocardiogram. An ECG test can help doctors monitor the electrical activity of the heart. This can also help the doctors assess any other irregularity in the heart rate. An accelerated heart rate or a very slow heart rate, which are medically referred to as tachycardia and bradycardia respectively, can also be diagnosed with the help of an ECG test.
At times, the irregularity in the heartbeat might not be revealed by a routine ECG, therefore, a holter monitoring device might be used for monitoring intermittent arrhythmia. Unlike RSA, other types of arrhythmia such as sick sinus syndrome, premature atrial contraction, atrial flutter, atrial fibrillation, and ventricular fibrillation might be indicative of cardiac problems.
Since fluctuations in the normal sinus rhythm might be indicative of heart problems, individuals affected by heart arrhythmia must have their heart rate monitored at regular intervals. RSA is prominent in children and young adults and generally resolves on its own as one ages. However, individuals affected by very fast and irregular heartbeat, very slow heartbeat, escape beats, or other symptoms of arrhythmia must consult a doctor immediately.
At times, the irregularities in the heartbeat might be caused due to medical conditions such as diabetes, hypertension, or heart diseases. Lifestyle-related issues such as smoking, alcohol abuse or drug abuse could also make one susceptible to arrhythmia.
As far as the treatment is concerned, drug therapy, making certain lifestyle-related changes, or the use of implantable devices such as automatic defibrillator or an artificial pacemaker might prove beneficial. At times, surgical procedures might be recommended.
RSA is generally benign and doesn’t cause any serious repercussions on one’s health, however, people affected by other types of arrhythmia must seek medical assistance. Since cardiac arrhythmia might be indicative of an underlying heart disease, timely diagnosis and treatment will surely help in preventing serious complications from arising.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.