The paroxysmal supraventricular tachycardia ekg
The paroxysmal supraventricular tachycardia ekg Paroxysmal supraventricular tachycardia (PSVT) is a common arrhythmia characterized by sudden episodes of rapid heart rate that originate above the ventricles. Patients often experience abrupt onset and termination of symptoms, which include palpitations, dizziness, shortness of breath, and sometimes chest discomfort. The electrocardiogram (EKG or ECG) plays a crucial role in diagnosing PSVT, offering vital clues that help differentiate it from other cardiac arrhythmias.
On the surface, the EKG during a PSVT episode typically shows a narrow QRS complex tachycardia, with a heart rate often ranging from 150 to 250 beats per minute. The hallmark feature is the regularity of the rhythm combined with a rapid rate. Unlike ventricular tachycardia, where QRS complexes are wide and abnormal, PSVT’s narrow complexes reflect its supraventricular origin, common in the atria or the AV node. The paroxysmal supraventricular tachycardia ekg
One of the most distinctive features on the EKG is the absence or abnormality of visible P waves. In many cases, P waves are either hidden within the QRS complex or appear immediately before or after it, making their identification challenging. The reason for this is the rapid conduction of impulses through the atrioventricular (AV) node, which often causes atrial activity to be superimposed on ventricular depolarization. When P waves are visible, they may be inverted in the inferior leads (II, III, aVF) if the atrial activation is retrograde, which is typical in AV nodal reentrant tachycardia (AVNRT), the most common form of PSVT. The paroxysmal supraventricular tachycardia ekg
The paroxysmal supraventricular tachycardia ekg The mechanism underlying PSVT often involves reentrant circuits within or around the AV node. In AVNRT, a small reentry pathway within the AV node causes rapid, repetitive impulses that lead to the tachycardia. On the EKG, this is often seen as a regular, narrow QRS tachycardia with P waves either embedded or appearing after the QRS complexes—sometimes called “pseudo R’ waves” in the V1 lead or “pseudo S waves” in the inferior leads.
Differentiating PSVT from other tachycardias is essential because treatment varies. For example, atrial flutter or fibrillation may have irregular rhythms, and ventricular tachycardia often produces wide QRS complexes. The response to maneuvers or medications can also help in diagnosis; vagal maneuvers like the Valsalva or carotid massage can terminate PSVT by increasing vagal tone, which slows conduction through the AV node. The paroxysmal supraventricular tachycardia ekg
In terms of management, understanding the EKG features guides acute intervention and long-term strategies. Vagal maneuvers and adenosine are often effective in terminating PSVT episodes, as they transiently block AV node conduction. Persistent or recurrent episodes may warrant further evaluation, including electrophysiology studies, and possibly ablation therapy targeting the reentrant pathway.
In conclusion, the EKG is an invaluable tool in diagnosing paroxysmal supraventricular tachycardia. Recognizing the characteristic narrow QRS complexes, regular tachycardia, and P wave morphology enables clinicians to distinguish PSVT from other arrhythmias swiftly, facilitating prompt and appropriate treatment to reduce symptoms and prevent complications. The paroxysmal supraventricular tachycardia ekg
