From the Guidelines
Supraventricular tachycardia (SVT) typically does have P waves, though they may be difficult to identify on an ECG. In SVT, the abnormal heart rhythm originates above the ventricles, in either the atria or the AV node. The presence and appearance of P waves varies depending on the specific type of SVT.
Types of SVT and P Wave Characteristics
- In atrial tachycardia, P waves are present but may have an abnormal shape and occur before each QRS complex.
- In AV nodal reentrant tachycardia (AVNRT), P waves often occur simultaneously with the QRS complex and may be hidden within it or appear as a small deflection at the end of the QRS, as described in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
- In atrial flutter, P waves appear as a sawtooth pattern.
- In contrast, atrial fibrillation shows chaotic, irregular atrial activity rather than distinct P waves.
Importance of P Wave Identification
The identification of P waves and their relationship to QRS complexes is crucial for differentiating between SVT subtypes and determining appropriate treatment strategies, which may include vagal maneuvers, medications like adenosine or beta-blockers, or in some cases, ablation procedures, as outlined in the ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias 1.
Clinical Considerations
A thorough clinical history and physical examination are essential in evaluating patients with SVT, as symptoms can vary widely and may include palpitations, fatigue, lightheadedness, chest discomfort, dyspnea, presyncope, or syncope 1. The pattern of SVT episodes, including frequency, duration, and mode of onset, is also critical in guiding clinical decision-making.
From the Research
SVT and P Waves
- SVT (Supraventricular Tachycardia) is characterized by an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above 2.
- The condition is caused by reentry phenomena or automaticity at or above the atrioventricular node, and includes atrioventricular nodal reentrant tachycardia, atrioventricular reciprocating tachycardia, and atrial tachycardia 3.
- P waves are a part of the electrocardiogram (ECG) that represents the depolarization of the atria, however, the provided studies do not explicitly state whether SVT has P waves or not.
- Diagnosis of SVT is made on electrocardiogram during an arrhythmic event or using ambulatory monitoring, which may include the presence or absence of P waves 4.
- The studies focus on the diagnosis, management, and treatment of SVT, including vagal maneuvers, adenosine, calcium channel blockers, and beta blockers, but do not provide detailed information about the presence of P waves in SVT 2, 5, 4, 3, 6.