Arrhythmias & electrophysiologyDiagnostic or prognostic study
Epinephrine Challenge
- Diagnostic test performance study in a registry
- consecutive patients
- long-term follow-up
Authors' conclusion
A positive epinephrine challenge demonstrated mild-moderate agreement with a final diagnosis of LQTS and CPVT. Most patients with an initial positive test result had their diagnosis revised to UCA, unaffected, or an alternative diagnosis over long-term follow-up. This study suggests that epinephrine challenge has limited utility as a "rule-in" test but may retain value in its negative predictive value for the UCA population.
Study context
- Population
- Consecutive patients undergoing epinephrine challenge in the Hearts in Rhythm Organization registry: patients with unexplained cardiac arrest (UCA) and first-degree relativesconsecutive patients undergoing epinephrine challenge · patients with unexplained cardiac arrest [UCA] 250 · first-degree relatives 176
- Participants
- 376 patients
- Comparison
- Epinephrine challenge for the diagnosis of long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT), comparing to final working diagnosis according to guideline-derived diagnostic criteria
Performance
As reported in the abstract
| Test or model | sensitivity | specificity | LR+ | Likelihood ratio (LR-) |
|---|---|---|---|---|
| epinephrine challenge | 90% | 79% | 4.4 (95% CI: 3.4-5.6) | 0.1 (95% CI: 0.0-0.4) |
Further findings
| Outcome | epinephrine challenge | final working diagnosis |
|---|---|---|
| Test performance of epinephrine for the diagnosis of CPVT · compared with final working diagnosis | ||
| sensitivity | 62% | Not reported in the abstract |
| specificity | 93% | Not reported in the abstract |
| LR+ | 8.9 (95% CI: 5.2-16.6) | Not reported in the abstract |
| LR- | 0.4 (95% CI: 0.2-0.8) | Not reported in the abstract |
QT prolongation with epinephrine vs end-recovery QTc on exercise stress testing
- No significant correlation
Pathogenic variant yield among patients with a positive epinephrine challenge
- pathogenic LQTS variant, of genotyped patients with a positive epinephrine challenge for LQTS
- 15%
- pathogenic CPVT variant, of patients with a positive epinephrine challenge for CPVT
- 13%
Final working diagnosis of patients with a positive epinephrine challenge
- Most had a "non-LQTS/CPVT" final working diagnosis (either UCA, unaffected, or an alternative Inherited arrhythmia syndrome)
Original publication
Summarised from the published abstract; every number is checked against it