Treatments for PSVT will depend on the frequency, duration and severity of the episodes as well as patient preference. Treatment for PSVT can be divided into acute treatment at the onset of an episode, chronic drug therapy or cardiac ablation for long-term management of the disease.
Patients may elect to not treat their symptoms and simply endure episodes when they occur and/or manage episodes by going to the ER. PSVT is not typically life threatening and some patients, especially patients with less frequent episodes, may elect to forego or discontinue ongoing oral medication due to side effects or ablation due to potential risks and/or expense. Vagal maneuvers can be attempted to terminate an episode, usually without success. However, many of these patients may still experience anxiety about the uncertainty of the timing of episodes and find their quality of life impacted as a result.
These are physiological maneuvers that stimulate the Vagus nerve which can terminate a PSVT episode and return the heart to a normal sinus rhythm. These include maneuvers such as gagging, holding one’s breath and bearing down (Valsalva maneuver), immersing one’s face in ice-cold water (diving reflex), or coughing. Unfortunately, vagal maneuvers are relatively ineffective with success rates of 10%-20%. Some vagal maneuvers such as the carotid sinus massage may no longer be deemed appropriate due to the small possibility of neurological harm while being relatively ineffective.
IV Adenosine and other IV drugs
If an episode does not resolve on its own or with a vagal maneuver, patients may elect to go to the emergency room for an IV administration of adenosine. When given as a rapid IV bolus, adenosine slows conduction through the atrioventricular (AV) node and interrupts reentry pathways thereby restoring the heart back to normal sinus rhythm. Adenosine is quickly eliminated from the body (in less than 1 minute). Other drugs such as IV verapamil or IV diltiazem may be used as well.
In rare instances, drugs may fail to successfully restore sinus rhythm, necessitating synchronized cardioversion. Synchronized cardioversion should be performed for acute treatment in hemodynamically unstable patients that have failed vagal maneuvers and adenosine and other IV treatments.
Ongoing Drug Therapy
Chronic oral medication with beta-blockers or calcium channel blockers may prevent or decrease the frequency of PSVT episodes, however, break-through episodes may still occur.
Beta-blockers, Beta-blockers (e.g. metoprolol) block beta-receptors on cells that respond to epinephrine, a molecule produced by the adrenal gland that stimulates the heartbeat. They slow and regulate the heart rate, reduce the force of heart contractions, and also lower blood pressure and relieve chest pain. These treatments are indicated daily or twice daily and according to the American Heart Association, the main side effects for these drugs include:
Calcium channel blockers Calcium channel blockers (e.g. verapamil and diltiazem) prevent calcium from entering the cells that transmit electrical signals. These treatments are indicated daily and according to the ACC/AHA/HRS Guidelines, the main side effects of these drugs include:
- worsening heart failure in patients with pre-existing ventricular dysfunction
- abnormal liver function studies
Cardiac ablation is an invasive procedure where flexible electrical catheters are inserted into a vein typically in the groin, and threaded into the heart. Electrodes at the end of the wires transmit information about the heart’s electrical activity. If the electrophysiologist is able to locate the problematic tissues, he/she uses radiofrequency energy (similar to microwave heat) to destroy the small area of tissue that is causing the electrical impulses to “loop” back and cause the arrhythmia.
According to the ACC/AHA/HRS Guidelines, the success of ablation for AVNRT is 96%-97% with a recurrence rate of 5% and major complications occurring in 3% of the population. Similarly, in AVRT the success rate is estimated at 93% with 8% recurrence rate and 3% chance of major complications.