Milton W. Anderson

Atrioventricular and Ventriculoatrial Excitation in Wolff-Parkinson-White Syndrome (Type B) Temporary Ablation at Surgery

A patient with an atrial septal defect, paroxysmal tachycardia, and the Wolff-Parkinson-White syndrome (type B) had epicardial exploration to determine the nature of the excitation anomaly. Right bundle-branch block in association with the WPW syndrome (type B) was evidenced by the late activation (0.12 sec) of the epicardium over the outflow tract of the right ventricle. Early activation of the base of the right ventricle (near the atrioventricular groove at the right border of the heart) was interpreted as indicating an actively conducting atrioventricular muscle bridge (bundle of Kent) in this region. During paroxysms of tachycardia, the ventricular area excited much later than when sinus mechanism was present, and the adjacent right atrium was excited in sequence. This sequence supported the concept of a circus movement, that is, movement from atrium to ventricle via atrioventricular bundle (His) and ventricle to atrium via a muscle bridge (Kent). Injection of procaine into the base of the right ventricle abolished the pre-excitation of the ventricle.

Cor triatriatum: Hemodynamic and angiocardiographic diagnosis

Abstract Three cases of cor triatriatum are reported. Each patient presented with breathlessness and had signs of pulmonary hypertension, with electrocardiographic evidence of right ventricular overload. Plain radiographs of the chest showed moderate left atrial enlargement and changes indicative of pulmonary venous engorgement. Left atrial enlargement was confirmed in 2 cases by angiocardiography and was quantitated by measurement of the left atrial volumes. Hemodynamic studies revealed a considerable increase in the pulmonary arterial pressure (78 mm. Hg systolic and 32 mm. Hg diastolic to 125 mm. Hg systolic and 75 mm. Hg diastolic) and in the “wedge” pressure (28 mm. Hg systolic and 20 mm. Hg diastolic to 65 mm. Hg systolic and 18 mm. Hg diastolic), with normal left ventricular end-diastolic pressures. Angiocardiography was performed in 2 patients, and in each the intra-atrial diaphragm was clearly demonstrated. Removal of the left atrial diaphragm was successful in 2 patients. The third patient, who had severe pulmonary vascular disease, died on the first postoperative day.

Valvular heart disease in older people.

Chronic valvular heart disease was found in 8.3 per cent of patients 50 years of age or older who were necropsied at the Mayo Clinic in 1950 and 1951. Although many lived to old age the valvular deformities presented hazards which indicate that ante- mortem recognition is of importance.

Severe Hyperkalemia in a Case of Chronic Renal Insufficiency

Severe hyperkalemia in the presence of chronic renal insufficiency may cause fatal cardiac arrest unless diagnosed early and treated promptly.Hyperkalemia may be diagnosed immediately through study of serial electrocardiographic tracings. The first electrocardiographic changes observed seem related to a disturbance in depolarization, excitation or conduction processes.Medical treatment of hyperkalemia includes reduction of potassium intake and protein catabolism, correction of renal acidosis, and maintenance of an adequate urinary output.