Unravelling the cause of idiopathic ventricular fibrillation: diagnostic testing during follow-up
R Roodenburg, L M Verheul, J C Balt, S C Yap, P G A Volders, P G Postema, A A M Wilde, R J HassinkAbstract
Background
When a patient survives a sudden cardiac arrest, an extensive diagnostic work-up is indicated to reveal the underlying cause. The diagnosis idiopathic ventricular fibrillation (IVF) is made when the cause of the arrest remains elusive after this extensive work-up. While the indicated diagnostic work-up to diagnose IVF is clear, guidelines regarding follow-up diagnostics are currently missing although repeating echocardiogram might reveal a structural disease.
Purpose
Investigating the current use and yield of transthoracic echocardiogram (TTE) during follow-up of patients initially diagnosed with IVF.
Methods
Patients were included from the Dutch IVF registry. Data were retrospectively collected on the application of TTE, its diagnostic yield, and whether the findings of TTE led to additional diagnostic testing or a change in treatment.
Results
A total of 476 patients initially diagnosed with IVF were included (62% male, median age 40 [28-52] years). The median follow-up duration was 14 [9-20] years during which 45 patients (10%) received an alternative diagnosis. A total of 959 TTE’s were performed in 356/459 (78%) patients with a median of 2 [1 – 4] per patient. The first follow-up TTE was performed after a median of 4 [2 – 7] years (Figure 1). In 5/356 (1%) patients the TTE resulted in an alternative diagnosis (Figure 2). Four patients were diagnosed with dilated cardiomyopathy. For one patient the finding of reduction in left ventricular ejection fraction was not further specified. After 14/754 (1.9%) TTE’s additional diagnostic testing was indicated. In 6/754 (0.7%) TTE’s the results led to an alteration in pharmacological treatment. In 3/754 (0.4%) TTE’s a significant valve lesion was found, and valve surgery was indicated. In one case (0.2%), the TTE revealed a lead endocarditis, and the ICD was subsequently explanted.
Conclusion
Follow-up TTE’s were performed in most IVF patients. However, approximately one in five patients did not receive a TTE during follow-up. The yield for an alternative diagnosis after TTE appears low (1%). TTE indicated additional diagnostic testing or a change in treatment in 3% of TTE’s. Further research is necessary to advise on a specific diagnostic work-up including timeframe and the use of more advanced techniques such as deformation imaging to possibly reveal structural abnormalities during follow-up.Figure 1:TTE performed during follow-upFigure 2:Yield of TTE during follow-up