September 23, 2005European Heart Journal
Syncope following cardioverter defibrillator implantation in patients with spontaneous syncopal monomorphic ventricular tachycardia
Key result
Non-syncopal monomorphic VT linked to ~81% lower risk of post-ICD syncope versus syncopal VT.
- HR 0.19
- 95% CI 0.04-0.42
- P=0.0001
- n=76
Why the study?
The incidence, mechanisms, and time to syncope recurrence in patients with spontaneous syncopal monomorphic ventricular tachycardia treated with an ICD needed to be determined.
Does spontaneous syncopal monomorphic ventricular tachycardia (SyMVT) predict a higher incidence of syncope following ICD implantation compared to non-syncopal MVT?
Key Points
- This research aims to examine the incidence and mechanisms of syncope after ICD implantation in patients with spontaneous syncopal monomorphic ventricular tachycardia.
- Comparison of syncope incidence in 26 patients with spontaneous SyMVT and 50 patients with NSyMVT
- Follow-up duration of 31±21 months for SyMVT and 34±23 months for NSyMVT
- Assessment of causes of syncope, including arrhythmic and non-arrhythmic events.
- 46% of SyMVT patients experienced syncope compared to 2% of NSyMVT patients (HR 0.19, 95% CI 0.04-0.42, P=0.0001)
- 15% of SyMVT patients had non-arrhythmic syncope, while 31% had arrhythmic syncope associated with ICD proarrhythmia or spontaneous VT/VF
- Median time to first arrhythmic syncope was 376 days, with events often following previous non-syncopal VT.
Study Design
Type
Cohort (n=76)
Structured PICO
Does spontaneous syncopal monomorphic ventricular tachycardia (SyMVT) predict a higher incidence of syncope following ICD implantation compared to non-syncopal MVT?
P
Population
76 consecutive patients with spontaneous monomorphic ventricular tachycardia treated with an ICD (26 syncopal, 50 non-syncopal), followed for a mean of 31 to 34 months.
E
Exposure
Implantable cardiac defibrillator (ICD) implantation in patients with spontaneous syncopal monomorphic ventricular tachycardia (SyMVT)
C
Comparator
Implantable cardiac defibrillator (ICD) implantation in patients with spontaneous non-syncopal monomorphic ventricular tachycardia (NSyMVT)
O
Outcome
Incidence, mechanisms, and time to syncope recurrence following ICD implantationhard clinical
Main Result
Hazard Ratio: 0.19 (95% CI 0.04–0.42)
Absolute Event Rate: 46% vs 2%
p-value: p=0.0001
Syncope recurrence is common after ICD implantation in patients with syncopal monomorphic VT, suggesting a need to reassess driving restrictions in this high-risk population.
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Syncope at spontaneous VT presentation identifies a subset of patients with high risk of syncope following ICD implantation, despite similar left ventricular ejection fraction, tachycardia cycle length, and device programming that patients presenting with no syncope at VT documentation. This risk cannot be extrapolated to other ICD populations.”
LMLluís MontElectrophysiologist, Hospital Clinic Barcelona
“therapies such as LESs should probably be avoided”
Implication
Higher syncope incidence after ICD in spontaneous syncopal VT warrants closer monitoring; observational data leaves open prospective validation and management strategies.
Abstract
AIMS: We sought to determine the incidence, mechanisms, and time to syncope recurrence in patients with spontaneous syncopal monomorphic ventricular tachycardia (SyMVT) treated with an implantable cardiac defibrillator (ICD). METHODS AND RESULTS: Incidence and causes of syncope following ICD implantation in consecutive patients (n=26) with spontaneous SyMVT were compared with those found in consecutive patients (n=50) with spontaneous non-syncopal monomorphic ventricular tachycardia (NSyMVT). Patients with SyMVT had a higher incidence of syncope (46% patients) than those with NSyMVT (2% patients) at 31+/-21 and 34+/-23 months follow-up, respectively (hazard ratio, 0.19; 95% confidence interval, 0.04-0.42; P=0.0001). Among the former, four patients (15%) had non-arrhythmic syncope and eight patients had arrhythmic syncope (31%), which was associated with either ICD proarrhythmia (seven episodes of VT acceleration or VF degeneration by ATP or low/high-energy shocks in three patients) or spontaneous VT and VF (five episodes in five patients). Median time to the first arrhythmic syncope was 376 days. Arrhythmic syncope presented after a first non-syncopal VT recurrence in six patients (75%). CONCLUSION: Syncope following ICD implantation is common in patients with SyMVT in contrast to patients with NSyMVT. Late syncope presentation supports reassessment of driving restrictions in this setting.
Discussion
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Cite This Study
Abello et al. (2005) conducted a cohort in Spontaneous monomorphic ventricular tachycardia treated with an implantable cardiac defibrillator (ICD) (n=76). Spontaneous syncopal monomorphic ventricular tachycardia (SyMVT) vs. Spontaneous non-syncopal monomorphic ventricular tachycardia (NSyMVT) was evaluated on Incidence of syncope following ICD implantation (HR 0.19, 95% CI 0.04-0.42, p=0.0001). Spontaneous syncopal monomorphic ventricular tachycardia was associated with a higher incidence of post-ICD syncope compared to non-syncopal VT (46% vs 2%; HR 0.19; 95% CI 0.04-0.42; P=0.0001).