Clinical experiences of patients with catecholaminergic polymorphic ventricular tachycardia

Abstract

Catecholaminergic polymorphic ventricular tachycardia is a rare entity that can occur in children without cardiac disease and with a normal QT interval. It may cause syncope, convulsions, and sudden death during physical activity or emotional distress. We report the clinical features, treatment, and follow-up of 16 children with this diagnosis, emphasizing the potentially fatal nature of the disease.The mean age of patients at the onset of symptoms and at the time of diagnosis was 7.8 plus or minus 2.5 years, and 10.6 plus or minus 3.5 years, respectively. Syncope was the main complaint in 11, and 7 were treated as erroneously as having epilepsy. Diagnosis was confirmed by exercise and/or infusion of isoproterenol. Once the diagnosis was made, we started propranolol in all patients, and added verapamil if ventricular tachycardia was still inducible on a treadmill exercise test. An intracardiac defibrillator was implanted in 4 patients. Of the 16 patients, 4 died suddenly, giving a rate of mortality of 25%. In 2 of those dying suddenly, there was evidence of poor compliance to the recommended treatment. Another 2 patients had been resuscitated because of sudden cardiac arrest.Catecholaminergic polymorphic ventricular tachycardia must be considered in the differential diagnosis of syncope in children without heart disease but with a normal QT interval. Medical treatment with propranolol and verapamil may decrease the incidence of arrhythmia. Implantation of intracardiac defibrillators should be considered in those resistant to drug therapy. Delay in diagnosis, and inadequate treatment, can result in sudden cardiac death.

Efficacy of Implantable Cardioverter Defibrillators in Young Patients With Catecholaminergic Polymorphic Ventricular Tachycardia

“…Overall, 46% of patients experienced an inappropriate discharge, a significantly higher percentage than the published rates of 25% to 30% in other pediatric device patients. 23 Our study confirmed high rates of inappropriate discharge for supraventricular arrhythmias, as previously reported 3,5,6 ; however, we also found that spontaneous termination of ventricular arrhythmias accounted for an equally high rate of inappropriate discharge. This has not been previously reported and is an important consideration in terms of ICD programming for these patients.…”

“…2-4,6,10,11,15 β-blockers are not always effective, 2,3,6,10,12,16 and in some patients, ICD and left cardiac sympathetic denervation are being used as management strategies. 17 However, death can occur, despite ICD implantation.…”

“…9,11 Reports have shown that ICD therapy can be ineffective or dangerous, 9,11,12 but no mechanism for this phenomenon has been established. Furthermore, previous studies have suggested that inappropriate discharges are secondary to supraventricular arrhythmias 3,5,6 (Table 1; online-only Data Supplement). Our study found that (1) the rate of appropriate therapy is high, but only half are effective, (2) effective therapy is likely related to arrhythmia mechanism, and (3) inappropriate therapy is because of both supraventricular arrhythmias and spontaneous termination of arrhythmia before ICD discharge.…”

“…1 Early onset of symptoms has been associated with a more malignant clinical course and sudden death rates have been reported to be as high as 25% to 50% by the age of 30 years. [2][3][4][5][6] Arrhythmias associated with CPVT are classically polymorphic or bidirectional VTs triggered by adrenergic stimulation; however, ventricular fibrillation (VF) and atrial arrhythmias can also be seen. 5,[7][8][9] Although antiarrhythmic therapy has been the first-line approach to managing these patients, implantable cardioverter-defibrillators (ICDs) are also used as a treatment strategy.…”

Clinical and genetic profile of catecholaminergic polymorphic ventricular tachycardia in Hong Kong Chinese children

“…Many affected children are considered to have vasovagal syncope or epilepsy before a correct diagnosis is made. [1][2][3][4] If left untreated, the mortality of CPVT is up to 31% by the age of 30 years. 1,3,5 In this study, we reviewed the clinical characteristics, genetic profile, and outcome of CPVT in Hong Kong Chinese children.…”