Saw-Tooth ECG Pattern: What Does It Mean?

Introduction

A saw-tooth pattern on an electrocardiogram (ECG) is a hallmark finding of a cardiac arrhythmia called atrial flutter. Understanding what this pattern means is crucial for diagnosing and managing this heart rhythm disorder.

What Is Atrial Flutter?

Atrial flutter is a type of supraventricular tachycardia (SVT)—a fast heart rhythm originating from the atria (upper chambers of the heart). It occurs when there is a rapid, regular electrical circuit in the right atrium, typically with a rate of about 250–350 beats per minute.

ECG Findings in Atrial Flutter

The distinctive 'saw-tooth' ECG pattern is seen in the P waves, best observed in leads II, III, and aVF. This pattern occurs due to rapid, continuously oscillating atrial activity without a clear isoelectric baseline.

Other key ECG findings include: - Absence of normal P waves due to continuous atrial depolarization. - Regular or irregular QRS complexes, depending on AV conduction. - Atrial rate of 250–350 bpm, though not all impulses conduct to the ventricles.

Symptoms of Atrial Flutter

Some patients may be asymptomatic, while others experience: - Palpitations (rapid heartbeat) - Dizziness or lightheadedness - Shortness of breath - Fatigue - Chest discomfort

Causes and Risk Factors

Atrial flutter is often seen in patients with: - Hypertension - Coronary artery disease - Heart failure - Chronic obstructive pulmonary disease (COPD) - Post-cardiac surgery or after heart procedures like ablation for atrial fibrillation

Possible Complications

If left untreated, atrial flutter can lead to: - Stroke: Due to formation of blood clots in the atria - Heart failure: Especially in patients with pre-existing heart disease - Conversion to atrial fibrillation: A more irregular and harder-to-control rhythm disorder

Treatment Strategies

1. Rate Control:
   • Beta-blockers (e.g., metoprolol, bisoprolol)
   • Calcium channel blockers (e.g., diltiazem, verapamil)
2. Rhythm Control:
   • Electrical cardioversion (if unstable or symptomatic)
   • Antiarrhythmic drugs (e.g., amiodarone, sotalol, flecainide)
   • Catheter ablation (definitive treatment in recurrent cases)
3. Stroke Prevention:
   • Anticoagulation therapy (e.g., warfarin, DOACs like apixaban, rivaroxaban) based on CHA₂DS₂-VASc score

Conclusion

If you or someone you know has experienced symptoms of atrial flutter, it is important to seek medical attention. Early diagnosis and management can prevent serious complications like stroke and heart failure.

Source recommendations

1. 2023 European Society of Cardiology (ESC) Guidelines for the Management of Atrial Fibrillation

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Atrial-Fibrillation
2. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
3. https://www.jacc.org/doi/10.1016/j.jacc.2023.10.021
4. https://pubmed.ncbi.nlm.nih.gov/32860505/
5. https://academic.oup.com/eurheartj/pages/esc_guidelines

2. 2020 American Heart Association (AHA)/American College of Cardiology (ACC)/Heart Rhythm Society (HRS) Guideline for the Management of Atrial Fibrillation

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
2. https://pubmed.ncbi.nlm.nih.gov/38033089/
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000665
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2020/12/04/20/16/2020-Update-to-ACC-AHA-AF-AFL-Performance
5. https://pubmed.ncbi.nlm.nih.gov/30686041/