Patients at Risk for Developing Supraventricular Tachycardia (SVT)
Patients with pre-excitation syndromes (particularly Wolff-Parkinson-White syndrome), structural heart disease, and certain demographic factors (women, older adults) are at highest risk for developing SVT. 1
Primary Risk Factors
Demographic and Physiologic Factors
- Age: Individuals >65 years have >5 times the risk of developing PSVT compared to younger persons 1
- Sex: Women have twice the risk of men of developing PSVT 1
- Pregnancy: Increased cardiac output and elevated resting heart rate during pregnancy predispose women to SVT 2
Pre-excitation Syndromes
- Wolff-Parkinson-White (WPW) syndrome: Patients with overt ventricular pre-excitation on ECG have a high risk of developing SVT, particularly AVRT 1
Structural Heart Disease
- Left ventricular hypertrophy (LVH): Most important predictor for supraventricular arrhythmias 1
- Valvular heart disease: Particularly aortic stenosis 1
- Hypertrophic cardiomyopathy 1
- Congenital heart disease: Especially patients with single-ventricle physiology 3
- Twin atrioventricular nodes present in 60% of these patients 3
Secondary Risk Factors
Cardiac Electrical Abnormalities
- Frequent supraventricular ectopic beats (SVPBs): Especially in patients with LVH 1
- Even short runs of 20-50 SVPBs are associated with increased risk of developing AF 1
- Non-dipping blood pressure profile: Associated with more advanced target organ damage and higher risk of arrhythmias 1
Other Medical Conditions
- Hypertension: Particularly when associated with LVH 1
- Recovery from exercise may be a triggering factor for SVPBs and subsequent occurrence of AF 1
- Pulmonary disease: Associated with multifocal atrial tachycardia (MAT) 1
- Sleep-disordered breathing: Associated with bradyarrhythmias that may predispose to SVT 1
- Cerebrovascular disease: May be associated with SVT 1
Clinical Presentation Patterns
The risk of adverse outcomes from SVT increases in patients who present with:
- Syncope: Observed in approximately 15% of SVT patients, usually after initiation of rapid SVT or with prolonged pause after termination 1
- Persistent tachycardia: SVT that persists for weeks to months with fast ventricular response may lead to tachycardia-mediated cardiomyopathy (approximately 1% of cases) 1, 4
- Hemodynamic instability: Patients with severe symptoms during palpitations require prompt evaluation 1
Risk Stratification Algorithm
High Risk: Immediate referral to arrhythmia specialist
- Patients with WPW syndrome (pre-excitation + arrhythmias)
- Patients with wide complex tachycardias of unknown origin
- Patients with severe symptoms (syncope, dyspnea) during palpitations
Moderate Risk: Evaluation and possible referral
- Patients with structural heart disease (LVH, valvular disease)
- Patients with frequent SVPBs and evidence of LVH
- Older adults (>65 years) with symptoms of palpitations
- Pregnant women with palpitations
Lower Risk: Monitoring and lifestyle modifications
- Younger patients with infrequent episodes
- Patients with identifiable triggers (stress, caffeine, alcohol)
Important Clinical Caveat
While SVT is generally considered benign, certain high-risk features warrant immediate attention:
- Pre-excitation with irregular and paroxysmal palpitations strongly suggests episodes of atrial fibrillation, requiring immediate electrophysiological evaluation due to risk of sudden death 1
- Patients with WPW syndrome and atrial fibrillation/flutter should undergo catheter ablation due to risk of ventricular fibrillation 1
Recognizing these risk factors allows for appropriate risk stratification and management decisions to reduce morbidity and mortality associated with SVT.