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Familial sudden death syndrome with an abnormal signal-averaged electrocardiogram as a potential marker
J W Chambers1, P Denes, W Dahl
1Cardiology Section, St. Paul Ramsey Medical Center, Minn, USA.
Insights
This study investigated a rare familial sudden cardiac death syndrome. An abnormal signal-averaged electrocardiogram may indicate a risk for sudden death in families with structurally normal hearts.
Area of Science:
- Cardiology
- Genetics
- Electrophysiology
Background:
- Familial sudden cardiac death (SCD) syndromes often link to structural heart disease or ECG abnormalities.
- The role of signal-averaged electrocardiograms (SAECG) in these syndromes remains unclear.
Observation:
- A family with unexplained SCD and normal hearts/12-lead ECGs was studied.
- Affected individuals had ventricular arrhythmias, normal autopsies, and normal 12-lead ECGs.
- Two survivors with arrhythmic events showed abnormal SAECGs and inducible ventricular arrhythmias.
Findings:
- This SCD syndrome is unique, presenting with anatomically normal hearts and normal 12-lead ECGs.
- Abnormal SAECGs correlated with inducible ventricular arrhythmias in affected family members.
- Normal SAECGs were observed in unaffected family members.
Implications:
- SAECG may serve as a valuable diagnostic marker for identifying individuals at risk in this specific SCD syndrome.
- Further research can elucidate the genetic basis and precise mechanisms of this unique SCD predisposition.
- Early identification via SAECG could enable timely interventions and potentially prevent sudden cardiac events.
Abstract:
Most familial sudden cardiac death syndromes are associated with structural heart disease or 12-lead electrocardiographic abnormalities. Additionally, the utility of signal-averaged electrocardiograms in patients with familial sudden death syndromes has not been examined. We studied a kindred with sudden death to determine whether they could be classified into any of the previously described syndromes and whether an abnormal signal-averaged electrocardiogram is a marker for this trait. Surviving family members had normal 12-lead electrocardiograms and echocardiograms. Two of the patients who died from ventricular arrhythmias had normal hearts on autopsy. Two surviving family members had a clinical history of arrhythmic events; both had abnormal signal-averaged electrocardiograms and inducible ventricular arrhythmias during electrophysiologic studies. The other family members had normal signal-averaged electrocardiograms. This familial sudden death syndrome appears to be unique because the patients have anatomically normal hearts and normal 12-lead electrocardiograms. An abnormal signal-averaged electrocardiogram may be a marker for the sudden death trait.