Table of Contents
Definition of Paroxysmal Atrial Tachycardia
An arrhythmia disorder, also called paroxysmal supraventricular tachycardia (PSVT), in which the atria have episodes of rapid, regular contractions. “Paroxysmal” means the symptoms start and stop abruptly, without apparent cause. During a PAT episode, the heart rate may reach 140 beats per minute.
The atrial contractions of PAT originate in the atrium above the atrioventricular (av) node rather than in the sinoatrial (sa) node that usually initiates the heart’s electrical pacing impulses.
The normal path for pacing impulses is from the SA node through the atria to the AV node. Many people who have PAT have more than one conduction pathway at the AV node. Errant electrical impulses from myocardial cells in the atrium can activate the alternate pathway, called an accessory pathway, triggering atrial contractions.
These are called reentrant atrial tachycardias; PAT is one variation. An episode of PAT may last a few minutes or several days. The longer the episode lasts, the more likely it is to produce symptoms.
Symptoms and Treatment
The primary symptoms of PAT are palpitations and lightheadedness, dizziness, or syncope (fainting). Some people experience chest pain, fatigue, and shortness of breath during an episode of PAT, though feel fine otherwise.
Diagnosis is by electrocardiogram (ecg), which may require Holter monitor to capture episodes as they occur. Treatment may include medications that can disrupt the accessory AV pathway, such as adenosine or calcium channel blockers.
Radiofrequency ablation, which destroys a small portion of the conductive pathway to prevent electrical impulses from traveling it, is often a viable treatment option for people with recurrent PAT and usually puts a permanent end to the episodes.