Paroxysmal Supraventricular Tachycardia (PSVT) and ECG Findings

Introduction

Paroxysmal supraventricular tachycardia (PSVT) is a condition characterized by sudden episodes of rapid heart rate due to abnormal electrical conduction in the heart. These episodes can start and stop suddenly and are typically due to reentrant circuits within the atria or the atrioventricular node.

Causes and Mechanisms

PSVT is usually caused by one of the following mechanisms: - Atrioventricular Nodal Reentrant Tachycardia (AVNRT): The most common, due to dual pathways in the AV node. - Atrioventricular Reentrant Tachycardia (AVRT): Involves an accessory pathway, as seen in Wolff-Parkinson-White (WPW) syndrome. - Atrial Tachycardia: A less common form caused by an ectopic focus within the atria.

ECG Findings in PSVT

Electrocardiography (ECG) plays a crucial role in diagnosing PSVT. Key findings include: - Narrow QRS complexes (unless there is an abnormal conduction such as bundle branch block). - Regular rapid rhythm (often between 150-250 bpm). - P waves may be hidden in the preceding T wave or visible with an atypical morphology. - Sudden onset and termination of tachycardia episodes.

Treatment and Management

• Acute Management:
  • Vagal maneuvers (Valsalva maneuver, carotid sinus massage).
  • Adenosine (a fast-acting AV nodal blocker) is the drug of choice for terminating AVNRT and AVRT.
  • Beta-blockers or calcium channel blockers may also be used in stable patients.
• Long-Term Management:
  • Catheter ablation is often recommended for recurrent cases.
  • Medications like beta-blockers or antiarrhythmic drugs may be used in less frequent cases.
  • Management of underlying conditions such as hyperthyroidism or electrolyte disturbances.

Conclusion

PSVT is a common arrhythmia that can cause palpitations, dizziness, and discomfort. ECG is essential for an accurate diagnosis, and both acute and long-term treatment strategies are available to prevent recurrences.

Source recommendations

1. American Heart Association (AHA) Guidelines on Supraventricular Tachycardia

1. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate
2. https://www.ahajournals.org/doi/10.1161/cir.0000000000000311
3. https://professional.heart.org/en/science-news/-/media/028ddd505f514ea2b3a4e74bb72e3557.ashx
4. https://pubmed.ncbi.nlm.nih.gov/26409259/
5. https://professional.heart.org/en/science-news/guideline-for-the-management-of-adult-patients-with-supraventricular-tachycardia

2. European Society of Cardiology (ESC) Guidelines on the Management of Supraventricular Tachycardia

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
2. https://academic.oup.com/eurheartj/article/41/5/655/5556821
3. https://pubmed.ncbi.nlm.nih.gov/31504425/
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2019/09/10/12/36/2019-ESC-Guidelines-for-Supraventricular-Tachycardia
5. https://pubmed.ncbi.nlm.nih.gov/14563598/