a sinus arrhythmia
Sinus arrhythmia is a common, harmless condition that is not necessarily dangerous; however, it should be evaluated if accompanied by other signs of heart problems.

Sinus arrhythmia is a variation in normal sinus rhythm. It is a common, harmless condition, seen more often in children and young adults, and affects both males and females equally.

It is not necessarily dangerous. However, if a sinus arrhythmia is accompanied by other signs of heart problems, such as a heart flutter, pain in the chest, fatigue, dyspnea on exertion, and excessive perspiration, a medical evaluation is required to determine the underlying disease.

What is sinus arrhythmia?

The heart is a vital organ that works incredibly hard, beating more than one lakh times per day to fulfill the critical requirement of the distribution of oxygen and nutrients throughout the body.

The term sinus arrhythmia is defined in two terms.

  1. Sinus” refers to a pacemaker called sinoatrial node that is located in the upper right atrium (right upper chamber of the heart)
  2. An “arrhythmia” or “dysrhythmia” is an irregular heartbeat

Normally, electrical impulses initiate in the sinoatrial node, which causes the atrium to contract, thus forcing the blood down to the ventricles (lower chamber of the heart). This process is repeated 60 to 100 times a minute (a normal heart rate range).

A normal heart rhythm is a sinus rhythm found in healthy people, whereas sinus arrhythmia is an irregular heart rhythm that originates in the sinus node.

3 characteristics of sinus arrhythmia on electrocardiography

  1. Irregular heart rate
  2. Variation in the RR interval is greater than 0.12 seconds
  3. Monoform P waves

8 types of arrhythmias

  1. Sinus tachycardia: A fast heart rate (over 100 beats per minute) that can occur in response to pain, exertion, exercise, fever, hyperthyroidism, emotional conditions (such as stress, anxiety, fright, and excitement), hypoxia (low blood oxygen level), and stimulant drugs (such as caffeine, nicotine, and alcohol).
  2. Sinus bradycardia:
    • A slow heart rate (below 60 beats per minute)
    • Long pauses in between the heartbeats
  3. Respiratory sinus arrhythmia:
    • Heartbeats are tied to breathing
    • Heartbeat increases on inspiration (breathing in)
    • Heartbeat decreases on expiration (breathing out)
    • Typically occurs in children and young adults due to intermittent vagus nerve activation
  4. Supraventricular arrhythmia: Arrhythmia begins in the atria (upper chamber of the heart).
  5. Ventricular arrhythmia: Arrhythmia begins in the ventricles (lower chamber of the heart).
  6. Atrial fibrillation: The most found arrhythmia, which occurs due to uncoordinated atrial contractions.
  7. Ventricular fibrillation (V-fib): A medical emergency due to ineffective ventricular contractions.
  8. Atrial flutter: Arrhythmia caused by abnormal or rapid circuits in the atrium.

7 symptoms of sinus arrhythmia

Sinus arrhythmia is usually asymptomatic, but if symptoms occur, they may include:

  1. Chest discomfort
  2. Palpitations (the heart beating too fast or fluttering)
  3. Pounding heartbeats
  4. Dizziness
  5. Fatigue
  6. Difficulty breathing
  7. Syncope

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7 causes of arrhythmia

Arrhythmias can occur due to:

  1. Coronary artery disease
  2. An impending myocardial infarction
  3. Cardiomyopathies
  4. Valve disorders
  5. Electrolyte imbalance
  6. Hypothyroidism
  7. Post cardiac surgery

9 factors that can increase the risk of arrhythmias

Here are 9 factors that can increase the risk of arrhythmias:

  1. Obesity
  2. A family history of heart disease
  3. Congenital heart disease
  4. Smoking
  5. Hypertension (high blood pressure)
  6. Hypercholesterolemia
  7. Alcohol consumption
  8. Tobacco or nicotine
  9. Excessive caffeine intake

How is an arrhythmia diagnosed?

Arrhythmia is often diagnosed accidentally during a routine examination or evaluation of some other medical condition.

After a thorough physical examination and history taking, a cardiologist (heart specialist) may recommend certain diagnostic tests to confirm the presence of arrhythmia and evaluate its causes.

  • Electrocardiogram: A study of the electrical activity of the heart.
  • Ambulatory monitors:
    • Stress test: A test to evaluate the worsening of arrhythmia with activity and helps determine the underlying cause.
    • Echocardiogram: Ultrasound waves are used to view the heart muscles.
    • Electrophysiology study (EPS): A catheter is inserted into the heart to record the electrical activity.
    • Cardiac catheterization: An X-ray-guided catheter is inserted into the heart and contrast dye is used to take images of the coronary arteries and heart valves.
    • Head-up tilt table test: The patient lies in a head-up position on the bed that is tilted in different angles while their heart rhythm and blood pressure are monitored and evaluated.

3 complications of arrhythmias

Here are 3 complications of arrhythmias:

  1. Stroke (reduced or impaired blood supply to the brain)
  2. Heart failure
  3. Death

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Medically Reviewed on 2/2/2022
References
Image Source: iStock Images

Soos MP, McComb D. Sinus Arrhythmia. [Updated 2021 Sep 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 https://www.ncbi.nlm.nih.gov/books/NBK537011/

Cleveland Clinic. Arrhythmia. https://my.clevelandclinic.org/health/diseases/16749-arrhythmia

Children’s Wisconsin. Arrhythmias. https://childrenswi.org/medical-care/herma-heart/conditions/arrhythmias