Functional capacity of patients with atrial fibrillation and controlled heart rate before and after cardioversion.

OBJECTIVE: To measure exercise duration (which frequently is diminished by atrial fibrillation) and to compare the gain in exercise duration achieved by heart rate control with the gain after cardioversion. METHODS AND RESULTS: Eighteen patients (10 with structural heart condition and eight with lone atrial fibrillation) did the treadmill exercise stress test using the Bruce protocol. Resting supine heart rate was lowered below 100 beats/min by verapamil (initial exercise stress test). An exercise stress test was then repeated as often as needed to achieve 'heart rate control' (less than 130 beats/min at the end of a 3 min walk at 10 degrees elevation and 2.74 km/h speed). This heart rate control was obtained by gradual increases in verapamil dose. Subsequently, the patients were converted to normal sinus rhythm chemically (seven patients) or electrically (11 patients) and an exercise stress test was repeated. At cardioversion, patients were on antiarrhythmic therapy and verapamil was discontinued in most. All patients had left atrial size measured by echocardiogram before and after cardioversion, and all were followed for four months. Upon achieving controlled heart rate, exercise duration increased in 16 patients (average gain was 164 s). After cardioversion to normal sinus rhythm, exercise duration further increased in 13 cases with an average additional gain of 90 s. The total increase in exercise duration after cardioversion was 254 s. Post cardioversion, all patients with lone atrial fibrillation improved. A decline in exercise performance occurred in four patients with fixed cardiac output. Average gain in exercise duration was independent of drugs used. Left atrial size remained increased post cardioversion (50.4 mm before and 52 mm after). During four months of follow-up, only eight patients could continue on the same medication given for cardioversion. Three patients did not maintain normal sinus rhythm. CONCLUSIONS: Conversion to normal sinus rhythm in patients with atrial fibrillation is associated with improved exercise tolerance except in cases with fixed cardiac output. Restoration of mechanical atrial function appears to be responsible for improved exercise performance following cardioversion.

Increased plasma endothelin-1 in the early hours of acute myocardial infarction.

Endothelin is a novel endothelium-derived vasoactive peptide with potent vasoconstrictor action in the coronary bed; however, its possible contribution to myocardial ischemia and infarction is not known. Plasma endothelin-1 concentration was measured with use of a radioimmunoassay in serial venous samples from 22 patients over a 72 h period after acute myocardial infarction (14 patients with uncomplicated infarction [group I] and 8 patients with hemodynamic or ischemic sequelae [group II]). Twenty-two normal subjects and seven patients with stable angina served as the control subjects. Endothelin-1 levels in patients with stable coronary disease were not different from those of normal subjects (0.62 +/- 0.56 and 0.76 +/- 0.38 pg/ml, respectively). In group I, plasma levels of endothelin-1 rose sharply after myocardial infarction, reaching a peak of 4.95 +/- 0.78 pg/ml at 6 h after the onset of chest pain (p less than 0.05 compared with values in control subjects) and returning rapidly toward the normal range by 24 h. Patients with complicated infarction (group II) demonstrated a similar rapid increase in plasma endothelin-1 to a peak value of 8.29 +/- 1.95 pg/ml; however, plasma endothelin-1 remained elevated in these patients, becoming significantly different from values in group I at 48 and 72 h. There was no correlation between peak increases in creatine kinase and peak endothelin-1 in either group, suggesting that the stimulus for elevation of endothelin-1 was not myocardial necrosis itself. Furthermore, left ventricular ejection fraction did not correlate with the increase in endothelin-1 in group I patients, whereas there was a significant inverse relation between ventricular function and plasma endothelin-1 in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiosarcoma of the heart.

A 17-year-old boy presented with severe chest pain which partially subsided on anti-inflammatory medication. Five week later he was admitted with fully developed cardiac tamponade. Within five days surgical exploration revealed an nonresectable right atrial tumour. Management of angiosarcoma of the heart is discussed.

The role of surgical exploration in the diagnosis of constrictive pericarditis. A case report.

Both constrictive pericarditis and restrictive cardiomyopathy present as biventricular failure. Although it is rarely necessary, surgical exploration may be required to definitively diagnose constrictive pericarditis. A case illustrating the value of surgical exploration is reported.

Comparison of 5F and 7/8F catheters for left ventricular and coronary angiography.

Fifty-two patients were randomized into two groups of 26 to the use of either 5 or 7/8F catheters for their first left heart cardiac catheterization. Clinical characteristics for the two groups were similar. 5F catheters were significantly inferior to 7/8F catheters in terms of torque control (P less than .001), ease of engaging coronary ostia (P less than .001), and quality of angiograms (P less than .05). Nine patients in the 5F group required a change to 7/8F catheters for completion of the procedure. There was no difference in procedure time or fluoroscopy time between the groups. Time to haemostasis was significantly shorter in the 5F group (P less than .01), but there was no difference between groups with respect to haematoma formation or rebleed after haemostasis. We conclude the slight advantage of 5F catheters in terms of haemostasis is outweighed by many disadvantages. Their routine use in cardiac catheterization, at least at this time, cannot be recommended.

Failure of amiodarone to prevent ventricular fibrillation (sudden death) in hypertrophic cardiomyopathy.

A case of ventricular fibrillation with successful resuscitation is described in a patient with hypertrophic cardiomyopathy and a history of syncope. Patients with hypertrophic cardiomyopathy who are at risk for sudden death can be identified by electrocardiographic monitoring which demonstrates episodes of ventricular tachycardia. Therapy with amiodarone has been shown to abolish ventricular tachycardia and to reduce the incidence of sudden death. Amiodarone therapy eliminated malignant ventricular ectopic activity in this patient during 48 h of ambulatory electrocardiographic monitoring, yet the subsequent exercise stress test provoked an episode of ventricular fibrillation.

Randomized double blind trial comparing sotalol and propranolol in chronic ventricular arrhythmia.

Sotalol is a beta-blocker which also prolongs repolarization. Its relative efficacy towards suppressing chronic ventricular arrhythmia was tested by comparison with propranolol. This double blind parallel comparison study involved 30 patients with or without coronary artery disease who had chronic symptomatic ventricular arrhythmia and more than an average of 30 premature ventricular complexes (PVCs) per hour. After the placebo baseline period patients received four weeks of active treatment with sotalol or propranolol. Responders were patients who had 75% or more reduction of PVCs during 24 h Holter monitoring. One patient in each treatment group had intolerable side effects on a low dose of the drug and were withdrawn. Side effects were present more frequently in the propranolol group compared with sotalol. Proarrhythmic effects were present in one patient on sotalol. There was no significant difference in suppression of ventricular extrasystoles (sotalol 65%, propranolol 44%), with reduction in ventricular couplets being 99% for sotalol and 49% for propranolol. There was a significant increase in QTc in patients on sotalol. Therefore, sotalol is a well tolerated drug and may be preferable to propranolol for control of chronic ventricular arrhythmia.

Safety of outpatient cardiac catheterizations.

Since 1979 most of the cardiac catheterizations at the investigators' institution have been performed as outpatient procedures. All cardiac catheterizations performed over a 66-month period were analyzed. A total of 3,071 outpatient cardiac catheterizations (83% of all cardiac catheterizations) were performed. The percutaneous femoral technique was used in 98% of the procedures. Most patients (79%) had both right and left-sided cardiac catheterization and coronary angiography, which showed significant coronary artery disease (70.4%). Only 13.6% of the study results were normal. Thirty-four patients (1.1%) had major complications, including 4 deaths (0.13%). Seventy patients (2.3%) were admitted for observation only. More than 96% of all patients did not have a major complication and were discharged the same day. Thus, outpatient cardiac catheterization can be performed safely, with a potential reduction in hospital costs and better utilization of medical beds.

Malignant granular cell myoblastoma with metastatic cardiac involvement: Case report and echocardiogram.

A malignant form of granular cell myoblastoma originating in the shoulder, gave rise to metastatic cardiac involvement causing infiltrative cardiomyopathy with heart block. The patient survived four months with a permanent pacemaker. The echocardiographic and histological features are described and the literature is reviewed. Features shown on the echocardiogram are indistinguishable from other causes of infiltrative cardiomyopathies.