Ventricular tachycardia induced cardiomyopathy: improvement with radiofrequency ablation.

Cardiomyopathy and congestive heart failure due to ventricular and supraventricular tachycardia is a well-recognized phenomenon. The mechanism of such cardiomyopathy is not clear. Ablation of the supraventricular tachycardia focus, either surgically or electrically, has been reported to result in the resolution of the left ventricular dysfunction. Similarly, the treatment of ventricular tachycardia with surgery or antitachycardia pacing has also been reported to result in improved ventricular systolic function. We present here a case of improvement in left ventricular systolic function after successful radiofrequency ablation of the ventricular tachycardia focus in the right ventricular outflow tract. We postulate that cardiomyopathy was due to the incessant or frequent ventricular tachycardia. To the best of our knowledge, this is the first such case being reported.

Adenotonsillar hypertrophy and cor pulmonale: clinical and echocardiographic correlation.

It is well recognized that upper airways obstruction by adenotonsillar hypertrophy can lead to cor pulmonale, but delays in diagnosis still occur, leading to an appreciable morbidity and even occasional mortality. In the case presented, echocardiographic recognition of right ventricular enlargement and abnormal pulmonary valve motion served to complement and confirm the clinical diagnosis. Following surgical relief of the airways obstruction, the echocardiographic examination usefully documented the regression in right ventricular size and the return to normality of pulmonary valve motion.

The effects of amiodarone on thyroid function.

The effects of amiodarone on thyroid function tests in 100 patients treated for 6 weeks to 8 years are reported. One patient became thyrotoxic and 10 developed latent or overt hypothyroidism. Twenty-five patients remained clinically euthyroid throughout, but had free thyroxine indices above the normal range. In these patients with apparently anomalous results, total tri-iodothyronine was normal in 19 cases and low in 1; conversely, free thyroxine was high in all 17 cases in which it was measured. Thyrotrophin releasing hormone (TRH) tests were abnormal in 4 of the 13 patients who had the test. Reverse tri-iodothyronine was significantly raised after 2 weeks amiodarone in 5 healthy subjects, but an equivalent amount of iodine in 9 healthy individuals did not significantly affect any of these tests. We believe that these changes are due in part to inhibition of peripheral conversion of thyroxine to tri-iodothyronine with diversion to reversed tri-iodothyronine. Thyroid function tests should be checked once or twice a year in all patients on maintenance amiodarone. Tests indicating hypothyroidism are likely to be clinically relevant, whereas levels of thyroxine suggesting thyrotoxicosis may be misleading and do not usually imply the need to discontinue treatment with the drug.

Ocular changes resulting from therapy with amiodarone.

Amiodarone, a powerful antiarrhythmic agent recently made available in Britain, is known to cause corneal changes, but the clinical implications of this unwanted effect are still controversial. We have made serial observations on 105 patients treated with the drug for periods ranging from 3 months to over 7 years. Corneal abnormalities were detected by slit-lamp examination in 103 patients (98%). These always progressed over several months but subsequently showed a stable pattern which changed only with alteration of dose. The abnormalities regressed and disappeared within 7 months in the 16 patients whose treatment was discontinued for reasons unconnected with ocular changes. No macular changes or permanent sequelae occurred. Ocular symptoms were unusual: 6 patients had reactions in the skin of the eyelids, and 6 others had minor symptoms related to the corneal changes. We do not believe that ophthalmological surveillance is mandatory in asymptomatic patients on long-term amiodarone therapy.

Use of an automated external defibrillator-pacemaker by ambulance staff.

A new portable external device detects ventricular fibrillation and profound bradycardia or asystole by analysis of wave forms; it automatically delivers a defibrillating shock or repetitive pacing stimuli. Ambulance crews used the device on 27 cardiac-arrest patients. The initial group (16) was restricted to patients prejudged as probably beyond successful resuscitation, and none survived. The subsequent group (11) was not restricted. 5 were discharged alive from the hospital. The device is simple to use, and its application by modestly trained technicians and lay people may be feasible. Widespread use of the device as an adjunct to conventional cardiopulmonary resuscitation could reduce mortality from out-of-hospital cardiac arrest. The capability for external cardiac pacing enhances the efficacy of treatment.

Role of labetalol in acute myocardial infarction.

1 The role of labetalol in managing acute myocardial infarction is reviewed. 2 After intravenous infusion labetalol lowers blood pressure in patients with increased blood pressure associated with acute myocardial infarction. 3 Although average heart rate was decreased, cardiac index fell only slightly and stroke index was substantially unchanged. 4 In patients whose pretreatment pulmonary artery end-diastolic pressures were increased, labetalol induced decreases, whereas in the presence of normal pressures, these were unchanged. 5 It is concluded that labetalol infusion in patients with acute myocardial infarction is unlikely to precipitate heart failure and is likely to be of value in reducing myocardial oxygen requirement.

Defibrillation at a football stadium: an experiment with Brighton and Hove Albion.

Over a five-year period arrangements have been made to increase the prospects of resuscitation for victims of sudden death at a large football stadium. Seven cases of ventricular fibrillation occurred. Four were resuscitated successfully and were subsequently discharged from hospital.