From the Guidelines
Paroxysmal sustained supraventricular tachycardia (SVT) is defined as a rapid heart rhythm disorder that originates above the ventricles, characterized by sudden onset and termination episodes with heart rates typically greater than 100 beats per minute. According to the European Heart Journal, the term SVT encompasses many tachyarrhythmias in which atrial and/or atrioventricular nodal tissues are required for initiating and sustaining the arrhythmia 1. The episodes of paroxysmal SVT start and stop abruptly, lasting from minutes to hours or even days.
Key Characteristics
- Sudden onset and termination of episodes
- Heart rates typically greater than 100 beats per minute
- Episodes can last from minutes to hours or even days
- Results from abnormal electrical pathways or mechanisms in the heart
Symptoms and Risks
- Common symptoms include palpitations, chest discomfort, fatigue, light-headedness, shortness of breath, anxiety, dizziness, dyspnoea, and, uncommonly, syncope
- Untreated SVT can result in heart failure (HF), pulmonary oedema, and/or myocardial ischaemia secondary to an increased heart rate, and in adults with congenital heart diseases (ACHD) SVT increased the risk of HF, stroke, and sudden cardiac death, as noted in the study published in the European Heart Journal 1.
Management
Immediate management can include vagal maneuvers, and if these fail, medications such as adenosine, beta-blockers, or calcium channel blockers may be used. Long-term management options include catheter ablation or regular medications like beta-blockers or calcium channel blockers to prevent recurrences. The management of paroxysmal sustained SVT should prioritize reducing morbidity, mortality, and improving quality of life, with a focus on preventing complications and recurrence.
From the Research
Definition of Paroxysmal Sustained SVT
- Paroxysmal supraventricular tachycardia (PSVT) is defined as tachyarrhythmias that originate from or conduct through the atria or atrioventricular node with abrupt onset 2.
- SVT is an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above 3.
- Paroxysmal SVT has three common types: atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and atrial tachycardia 3.
Characteristics of Paroxysmal SVT
- PSVT affects 168 to 332 per 100 000 individuals, with approximately 50% of patients aged 45 to 64 years and 67.5% female 2.
- Common symptoms include palpitations (86%), chest discomfort (47%), and dyspnea (38%) 2.
- Patients may rarely develop tachycardia-mediated cardiomyopathy (1%) due to PSVT 2.
Diagnosis and Management
- Diagnosis is made on electrocardiogram during an arrhythmic event or using ambulatory monitoring 2.
- First-line acute therapy for hemodynamically stable patients includes vagal maneuvers and intravenous adenosine 2, 4.
- Emergent cardioversion is recommended for patients who are hemodynamically unstable 2, 3.
- Catheter ablation is safe, highly effective, and recommended as first-line therapy to prevent recurrence of PSVT 2, 3, 5.