We describe rapidly fatal cardiomyopathy in a young man. He had for twelve months ingested large amounts of ascorbic acid and was admitted with severe heart failure having been symptomatic for two months. He died after eight days. Idiopathic haemochromatosis was diagnosed at autopsy. The clinical and laboratory features are discussed and the possible implications of ascorbic acid ingestion are explored.

Percutaneous endomyocardial biopsy (right ventricle in 10, left ventricle in 2) was performed in 12 patients, aged 9 to 57 years, with serious ventricular arrhythmias occurring in the setting of normal cardiac anatomy and mechanical function. Light microscopic examination of tissue revealed histologic abnormalities in 11 patients, including myocardial cellular hypertrophy in 7, interstitial fibrosis in 5, endocardial fibrosis in 2, myocardial degenerative changes in 1 and increased interstitial cellularity in 1. One patient had histologic evidence of acute lymphocytic myocarditis. Thus, a majority of patients with serious ventricular arrhythmias and normal cardiac anatomy had histologic abnormalities, bringing into question the concept of primary electrical heart disease or idiopathic ventricular tachycardia.

SUMMARY Four patients with myocardial dysfunction related to tachycardia underwent electrophysiological studies, which showed a re-entrant supraventricular tachycardia using an accessory atrioventricular connexion. Serial assessment of left ventricular function by echocardiography before and after control of the tachycardia indicated a variable degree of reversibility. Endomyocardial biopsy in two patients detected non-specific histological changes. Because of the possible role of ischaemia in this condition effective control of prolonged tachycardia is needed to prevent deterioration of myocardial function.Paroxysmal supraventricular tachycardia is usually well tolerated in the absence of underlying impairment of cardiac function.1-3 There are, however, published reports of patients with chronic or frequent episodes of supraventricular tachycardia who present with symptoms and with clinical and radiological signs of congestive cardiac failure.4-9 The patients in these reported cases were in general young, often in the paediatric age group. Many were without underlying cardiac disease, and with control of the tachyarrhythmia the symptoms and signs of congestive heart failure resolved. Detailed assessment of the mechanism of the arrhythmia and accurate serial determination of left ventricular function before and after the resolution of congestive heart failure, as A 16 year old girl had an episode of syncope which caused no personal injury. Supraventricular tachycardia (rate 160 beats/minute) was noted at the local hospital, and a chest x ray film showed cardiomegaly. She had been asymptomatic up to the time of the accident, and there was no history suggesting a recent viral illness or excessive alcohol consumption. Four weeks later she was referred to the Mayo Clinic with persistent tachycardia. She had remained asymptomatic. Chest x ray films showed cardiomegaly without pulmonary congestion, and an electrocardiogram showed a narrow complex supraventricular tachycardia (rate 150 beats/minute) with a long ventriculoatrial interval (Fig. 1). The P waves were negative in leads II, III, and aVF, and the ratio of the interval between the R wave and the retrograde P wave to the cycle length was >0*5, suggesting the permanent type of reciprocating junctional tachycardia. 12 The left ventricular ejection fraction measured during tachycardia by echocardiography (Fig. 2)

Propafenone was administered during electrophysiologic testing to determine its efficacy and safety for terminating and preventing reinduction of paroxysmal supraventricular reentrant tachycardia. Four men and 10 women (mean age 50 years, range 28 to 69) were studied. Five patients had Wolff-Parkinson-White syndrome with orthodromic atrioventricular (AV) reentrant tachycardia, three had a concealed accessory pathway with AV reentrant tachycardia and six had tachycardia due to reentry within the AV node. In the five patients with Wolff-Parkinson-White syndrome, propafenone terminated reentrant tachycardia in three (the tachycardia was reinducible in one) and had no effect in two. In the three patients with a concealed accessory pathway, propafenone terminated reentrant tachycardia in all three and prevented reinduction of the tachycardia in two. In the six patients with tachycardia due to reentry within the AV node, propafenone terminated and prevented reinduction of reentrant tachycardia. Propafenone had no effect on blood pressure, heart rate, PA interval, AV node refractoriness or rate of reentrant tachycardia. Propafenone significantly (p less than 0.05) prolonged the AH, HV, QRS and ventriculoatrial intervals and decreased the AV node Wenckebach rate. Of the nine patients receiving long-term oral propafenone therapy, eight had a reduction of at least 90% in reentrant tachycardia during a mean follow-up period of 14.5 months (range 11 to 22); all eight patients had had noninducible reentrant tachycardia after intravenous propafenone. One patient had increased frequency of reentrant tachycardia; this patient had had inducible reentrant tachycardia after intravenous propafenone. In conclusion, intravenously administered propafenone terminated reentrant tachycardia in 85% of patients and prevented reinduction in 71%, with no adverse hemodynamic effects.