From the Guidelines
Sinus arrhythmia is a normal variation in heart rhythm that does not require treatment, as it is considered a benign physiological response, especially in children, adolescents, and young adults. This condition is characterized by cyclic changes in heart rate that correspond with breathing, where the heart rate increases slightly during inhalation and decreases during exhalation. The mechanism behind this phenomenon is related to the effect of breathing on the pressure inside the chest cavity, which influences blood return to the heart, as described in the 2016 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Some key points to consider about sinus arrhythmia include:
- It is a normal physiological response that occurs in response to changes in breathing patterns
- The condition is usually harmless and does not require treatment
- Sinus arrhythmia is controlled by the vagus nerve, which helps regulate heart rate as part of the parasympathetic nervous system
- If symptoms like dizziness, fainting, chest pain, or shortness of breath occur, it is essential to consult a healthcare provider to rule out other cardiac conditions, as suggested in the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias 2.
In general, sinus arrhythmia tends to become less pronounced with age due to decreased autonomic nervous system responsiveness. The 2013 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities also provides insight into the management of cardiac rhythm abnormalities, including sinus bradycardia and intra-atrial re-entrant tachycardia 3. However, these guidelines do not directly address the management of sinus arrhythmia, reinforcing the notion that this condition is generally considered benign and does not require treatment.
From the Research
Definition and Classification of Arrhythmias
- Anything other than normal sinus rhythm can be classified as an arrhythmia, as stated in the study 4
- Not all arrhythmias need acute intervention, and the impact of an arrhythmia upon perfusion determines what intervention should be considered
Sinus Arrhythmia
- Respiratory sinus arrhythmia (RSA) is heart rate variability in synchrony with respiration, by which the R-R interval on an ECG is shortened during inspiration and prolonged during expiration, as described in the study 5
- RSA is a physiologic phenomenon reflecting respiratory-circulatory interactions universally observed among vertebrates
- The efficiency of pulmonary gas exchange is improved by RSA, suggesting that RSA may play an active physiologic role, as mentioned in the study 5
Factors Influencing Sinus Arrhythmia
- Ambulatory RSA magnitude is associated with respiratory variations and physical activity, as found in the study 6
- Adjustment for respiratory parameters substantially improves relations between RSA and significantly vagally mediated HR and physical activity
- Concurrent monitoring of respiration and physical activity may enhance HR variability accuracy to predict autonomic control, as suggested in the study 6
Electrolyte Disorders and Arrhythmogenesis
- Electrolyte disorders can alter cardiac ionic currents kinetics and depending on the changes can promote proarrhythmic or antiarrhythmic effects, as discussed in the study 7
- Potassium, calcium, and magnesium disorders can have significant electrophysiological and clinical consequences, including the development of arrhythmias such as torsade de pointes ventricular tachyarrythmia (TdP VT)