What are the risk factors for supraventricular tachycardia (SVT)?

Risk Factors for Supraventricular Tachycardia

The primary risk factors for SVT include female sex (2-fold increased risk), advancing age, congenital heart disease (10-20% prevalence), structural heart disease, and specific precipitating conditions including surgery, acute illness, and underlying cardiac comorbidities. 1

Demographic Risk Factors

Age

• Mean age of SVT onset is 57 years, with a broad range from infancy to over 90 years 1
• The incidence of atrial flutter increases dramatically with age: from 5 per 100,000 in those under 50 years to 587 per 100,000 over age 80 1
• Age of tachycardia onset differs by mechanism: AVNRT typically presents at 32±18 years versus AVRT at 23±14 years 1
• Older patients are more prone to syncope or presyncope with SVT, independent of heart rate 2

Sex

• Female sex confers a 2-fold greater relative risk of paroxysmal SVT (RR=2.0; 95% CI 1.0-4.2) compared to males 1
• Approximately 67.5% of PSVT patients are female 3
• Atrial flutter is 2.5 times more common in men 1

Structural and Congenital Heart Disease

Adult Congenital Heart Disease (ACHD)

• SVT occurs in 10-20% of ACHD patients, representing the highest-risk population 1, 4
• ACHD-associated SVT carries significantly increased risk of heart failure, stroke, and sudden cardiac death 1, 4
• Specific high-risk lesions include: 5
  • Ebstein's anomaly (strongly associated with accessory pathways and Mahaim fibers)
  • Tetralogy of Fallot
  • Transposition of the great arteries
  • Atrial septal defects
• Single-ventricle physiology patients have particularly complex SVT substrates, with 60% having twin AV nodes 6
• Right atrial isomerism patients have 72.2% prevalence of twin AV nodes 6

Acquired Structural Heart Disease

• Heart failure, hypertension, and chronic lung disease are associated with increased SVT risk 1
• Ischemic heart disease increases SVT susceptibility 1
• Only 1.7% of atrial flutter cases occur without structural cardiac disease or precipitating causes (lone atrial flutter) 1

Precipitating Conditions and Comorbidities

Acute Precipitants

• In approximately 60% of atrial flutter cases, SVT occurs for the first time in association with specific precipitating events: 1
  • Major surgery
  • Pneumonia
  • Acute myocardial infarction
• Postoperative junctional tachycardia occurs in 2-10% of young patients undergoing intracardiac surgery 1

Chronic Comorbidities

• Heart failure 1
• Hypertension 1
• Chronic obstructive pulmonary disease 1

Electrophysiologic Substrates

Accessory Pathways

• Patients with Wolff-Parkinson-White syndrome and pre-excitation on ECG are at risk for significant morbidity and possibly sudden death 4
• Manifested pre-excitation is present in 10% of single-ventricle CCHD patients 6
• Accessory pathways are particularly common in Ebstein's anomaly 5

Dual AV Nodal Pathways

• Dual AV nodal properties occur with increased probability in specific congenital heart defects 5
• Twin AV nodes are present in 60% of single-ventricle patients 6

Special Populations

Fetal SVT

• Sustained fetal SVT puts the fetus at risk of cardiovascular collapse manifested by hydrops 1
• Persistent SVT with hydrops carries high mortality rate 1

"Lone" PSVT Patients

• Younger than those with other cardiovascular disease (mean age 37 vs 69 years) 1
• Faster heart rates (186 vs 155 bpm) 1
• More likely to present first to emergency room (69% vs 30%) 1

Clinical Pitfalls

Common diagnostic delay occurs due to misdiagnosis as anxiety or panic disorder 7, emphasizing the importance of maintaining high clinical suspicion when patients report palpitations, particularly in young women with episodic symptoms.