Postextrasystolic "T wave hump" augmentation as a marker of increased arrhythmogenic risk in the long QT syndrome

Sudden cardiac death after treatment with low dose risperidone in combination with cotrimoxazole

Risperidone as an antipsychotic drug raises the risk of serious ventricular tachyarrhythmias and sudden cardiac death; co-administered with other potentially arrhythmogenic drugs the risk escalates. There are some electrocardiographic markers which may help predict such events.

CASE REPORT

We describe a 47-year-old woman with acute psychosis, who died suddenly subsequent to refractory ventricular arrhythmia, while on low dose risperidone combined with cotrimoxazole.

CONCLUSION

This case report suggests that use of risperidone even at a low dose and in an apparently healthy individual is associated with a heightened risk of lethal ventricular tachyarrhythmia. Therefore, clinicians should always be aware of such awkward effect. It is recommended to obtain baseline electrocardiogram in all patients and follow up electrocardiograms in selected patients when considering such therapy in order to avoid fatal outcomes.

Effective long-term control of cardiac events with beta-blockers in a family with a common LQT1 mutation

The congenital long QT syndrome (LQTS) is characterized by a prolonged QT interval on the surface electrocardiogram and an increased risk of recurrent syncope and sudden cardiac death. Mutations in seven genes have been identified as the molecular basis of LQTS. beta-blockers are the treatment of choice to reduce cardiac symptoms. However, long-term follow-up of genotyped families with LQTS has been rarely reported. We have clinically followed a four-generation family with LQTS being treated with beta-blocker therapy over a period of 23 years. Seven family members were carriers of two amino acid alterations in cis (V254M-V417M) in the cardiac potassium channel gene KCNQ1. Voltage-clamp recordings of mutant KCNQ1 protein in Xenopus oocytes showed that only the V254M mutation reduced the IKs current and that the effect of the V417M variant was negligible. The family exhibited the complete clinical spectrum of the disease, from asymptomatic patients to victims of sudden death before beta-blocker therapy. There was no significant reduction in QTc (556 +/- 40 ms(1/2) before therapy, 494 +/- 20 ms(1/2) during 17 years of treatment; n = 5 individuals). Of nine family members, one female died suddenly before treatment, three females of the second generation were asymptomatic, and four individuals of the third and fourth generation were symptomatic. All mutation carriers were treated with beta-blockers and remained asymptomatic for a follow-up up to 23 years. Long-term follow-up of a LQT1 family with a common mutation (V254M) being on beta-blocker therapy was effective and safe. This study underscores the importance of long-term follow-up in families with specific LQT mutations to provide valuable information for clinicians for an appropriate antiarrhythmic treatment.