Burst Exercise Testing Outperforms Traditional Bruce Protocol in CPVT Diagnosis and Management

Background

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited arrhythmogenic syndrome characterized by adrenergically mediated ventricular arrhythmias during physical or emotional stress. Exercise stress testing remains the cornerstone for diagnosing CPVT, yet traditional protocols like the Bruce may lack sensitivity, often leading to missed diagnoses and inadequate treatment. The Burst protocol, a sudden high-intensity exercise test, has emerged as a promising alternative to better unmask these life-threatening arrhythmias.

Study Design

This retrospective cohort study evaluated 28 pediatric and adult patients suspected of CPVT at two tertiary referral centers in Vancouver, Canada. Participants underwent consecutive Bruce and Burst exercise tests between May 2017 and May 2024. Arrhythmia severity was quantified using the Ventricular Arrhythmia Score (0-4), with higher scores indicating more severe arrhythmias. The primary outcome was the comparison of arrhythmia severity between the two protocols, with secondary outcomes including therapeutic changes and safety.

Key Findings

The Burst protocol demonstrated superior diagnostic yield, provoking more severe arrhythmias in 71% of patients compared to the Bruce protocol. The median Ventricular Arrhythmia Score was significantly higher with Burst testing (3 vs. 1, P<0.001). These findings led to treatment modifications—β-blocker or flecainide initiation or dose escalation—in 65% of patients. Importantly, no adverse events were reported during Burst testing, underscoring its safety profile.

Expert Commentary

The study highlights the clinical utility of the Burst protocol in CPVT management. Dr. Naderi and colleagues provide compelling evidence that this approach not only enhances diagnostic accuracy but also influences therapeutic decisions. However, the retrospective nature and small sample size warrant cautious interpretation. Future prospective studies are needed to validate these findings and assess long-term outcomes.

Conclusion

The Burst exercise stress test offers a safer and more effective alternative to the Bruce protocol for CPVT diagnosis and management. Its adoption into routine clinical practice could significantly improve patient outcomes by enabling timely and appropriate treatment adjustments.

Funding and ClinicalTrials.gov

This study was supported by institutional funding from the participating centers. No specific grant numbers or ClinicalTrials.gov identifiers were reported.

References

Naderi B, Li COY, Davies B, et al. Burst Exercise Stress Testing in Catecholaminergic Polymorphic Ventricular Tachycardia. JAMA Cardiol. 2026; PMID: 41949873.