The paroxysmal supraventricular tachycardia types
The paroxysmal supraventricular tachycardia types Paroxysmal supraventricular tachycardia (PSVT) is a common form of rapid heart rhythm that originates above the ventricles, characterized by sudden episodes of an abnormally fast heartbeat. These episodes can last from a few seconds to several hours, often causing symptoms like palpitations, dizziness, shortness of breath, and chest discomfort. Understanding the different types of PSVT is crucial for accurate diagnosis and effective management.
The paroxysmal supraventricular tachycardia types The primary classification of PSVT hinges on its underlying mechanism and specific electrophysiological pathways. Two main categories are atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT). While both result in rapid heart rates, they involve different conduction pathways within the heart’s electrical system.
AVNRT is the most prevalent type of PSVT, accounting for approximately 60-70% of cases. It occurs due to a reentrant circuit within or near the atrioventricular (AV) node itself. The AV node normally conducts impulses from the atria to the ventricles, but in AVNRT, an abnormal circuit causes the electrical impulse to loop within the node, leading to rapid heartbeats. This type often presents in young adults with no structural heart disease and is characterized by sudden onset and termination of episodes. The hallmark features include a narrow QRS complex on the electrocardiogram (ECG) and a retrograde P wave that may be hidden within or just after the QRS complex. The paroxysmal supraventricular tachycardia types
The paroxysmal supraventricular tachycardia types AVRT, on the other hand, involves an accessory pathway—a muscle bundle that creates an abnormal electrical connection between the atria and ventricles. This pathway allows a reentrant circuit to form outside the AV node, leading to tachycardia. The most common form of AVRT is Wolff-Parkinson-White (WPW) syndrome, which is identified by characteristic delta waves on the baseline ECG. During an episode, the ECG shows a wide QRS complex with a short PR interval, reflecting the pre-excitation of the ventricles. AVRT can be further classified into orthodromic and antidromic types, depending on the direction of conduction through the accessory pathway.
In addition to AVNRT and AVRT, another less common form involves atrial tachycardia, which originates from an ectopic focus in the atria rather than a reentrant circuit. This type can sometimes mimic PSVT but is distinguished by its different initiation and termination mechanisms, as well as distinct ECG features.
The paroxysmal supraventricular tachycardia types Diagnosing the specific type of PSVT involves detailed ECG analysis during an episode, sometimes supplemented with electrophysiological studies. These studies help pinpoint the precise pathway involved and guide treatment options. While many episodes of PSVT are benign and self-limited, recurrent episodes may require interventions such as medication, catheter ablation, or vagal maneuvers to terminate the episodes and prevent recurrence.
The paroxysmal supraventricular tachycardia types In conclusion, understanding the different types of paroxysmal supraventricular tachycardia provides essential insights into their mechanisms and management strategies. Whether it’s AVNRT, AVRT, or atrial tachycardia, accurate diagnosis allows for targeted treatment, significantly improving patient quality of life and reducing the risk of complications.
