Risk assessment in patients with symptomatic and asymptomatic pre-excitation

Area of Science:

• Cardiology
• Electrophysiology
• Clinical Risk Stratification

Background:

• Pre-excitation syndromes necessitate accurate risk stratification to prevent adverse events.
• The efficacy of exercise stress testing (EST) alone for risk evaluation in pre-excitation remains debated.
• Differentiating high-risk from low-risk accessory pathways is crucial for patient management.

Purpose of the Study:

• To evaluate the diagnostic utility of EST in stratifying risk in patients with pre-excitation.
• To compare the effectiveness of EST versus electrophysiology study (EPS) in identifying high-risk accessory pathways.
• To determine if symptom status influences the reliability of EST for risk assessment.

Main Methods:

• Prospective study of 164 consecutive patients (59 asymptomatic, 105 symptomatic) with pre-excitation undergoing both incremental bicycle EST and EPS.
• EST assessed for loss of pre-excitation during exercise.
• EPS measured accessory pathway effective refractory period (APERP) and shortest pre-excited RR interval (SPERRI), with isoproterenol used if necessary.

Main Results:

• Forty-five patients (27%) showed low-risk EST findings; 6 had high-risk EPS findings (SPERRI/APERP ≤ 250 ms).
• The negative predictive value of a low-risk EST for excluding high-risk APs was 51%.
• Inducible arrhythmias were found in 69% of asymptomatic and 61% of symptomatic patients during EPS.

Conclusions:

• Sudden loss of pre-excitation during EST is insufficient for excluding high-risk accessory pathways.
• Electrophysiology study (EPS), potentially with isoproterenol, is essential for accurate risk assessment in all pre-excitation patients.
• Symptoms do not negate the need for EPS in comprehensive risk evaluation.