Acute pseudogout in chronic renal failure.

Acute pseudogout (calcium pyrophosphate dihydrate deposition disease [CPPD disease]) developed in two patients with chronic renal failure. The disease had atypical features. The calcification of the involved joints was more diffuse than the usual linear stippled calcification. The first patient, age 39, was young to have pseudogout. The second patient had pseudogout and chondrocalcinosis limited to the elbow. Review of wrist roentgenograms of 82 patients (mean age, 49.0 years), undergoing hemodialysis for chronic renal failure revealed three patients (a 3.7% incidence) with chondrocalcinosis. The incidence increased to three of 19 (15.8%) in the patients over the age of 60. Although considered uncommon, pseudogout may cause acute arthritis in chronic renal failure more often than previously suspected. Joint aspiration and identification of CPPD cystals with compensated polarized light microscopy will establish the diagnosis of pseudogout.

Effects of changes in airway pressure on the left ventricle and left atrium of dogs.

The effects of negative and positive airway pressure were examined in eight closed chest, chronically instrumented dogs to determine beat to beat changes in left ventricular pressure, left ventricular dP/dt, left ventricular dimensions, and oesophageal pressure. As an index of afterload, systolic transmural pressure was calculated by subtracting oesophageal pressure from left ventricular pressure. With each change in airway pressure left ventricular end systolic minor axis diameter and left ventricular end diastolic minor axis diameter increased significantly. Left atrial end diastolic dimension increased significantly with negative airway pressure and did not change with positive airway pressure. Left ventricular dP/dt and left ventricular fractional shortening did not change. With the Mueller manoeuvre left ventricular systolic pressure decreased significantly from 106(4.2) mm Hg to 100.9(4.2) mm Hg and systolic transmural pressure increased significantly from 105.1(4.6) mm Hg to 110.4(4.3) mm Hg. With a transient increase in positive airway pressure of 30 mm Hg (4.0 kPa), left ventricular pressure increased significantly from 106.9(4.8) mm Hg to 113.9(5.9) mm Hg and systolic transmural pressure decreased significantly from 106.6(4.9) mm Hg to 99.8(4.6) mm Hg. The addition of positive end expiratory pressure of 10 cm H2O (0.98 kPa) or autonomic blockade with atropine and propranolol did not alter these results. Thus manoeuvres which cause opposite effects on systolic transmural pressure produce similar increases in left heart dimensions, suggesting that increases in pulmonary venous return and not changes in afterload may be the important determinants of left ventricular dimensional changes during changes in airway pressure.

Conversion of atrial fibrillation to sinus rhythm by acute intravenous procainamide infusion.

We evaluated the efficacy of an intravenous infusion of procainamide in 26 consecutive candidates for cardioversion of atrial fibrillation. Procainamide was administered at a rate of 15 to 20 mg/min up to a maximum of 1000 mg. The treatment was considered effective only if cardioversion occurred during the procainamide infusion. Conversion to sinus rhythm occurred in 15 patients. Converters had a significantly shorter mean duration of atrial fibrillation (6 +/- 7 days, mean +/- S.D.) compared to nonconverters (79 +/- 88 days) (p less than 0.01). The mean left atrial size of converters (4.3 +/- 0.6 cm) did not differ significantly from that of nonconverters (4.7 +/- 0.9 cm). The dose of procainamide required for cardioversion ranged from 3.6 to 16.4 mg/kg. Two patients developed nonsustained ventricular tachycardia, and there was one episode of bifascicular block during the infusion. Intravenous procainamide is an effective form of therapy for conversion of atrial fibrillation of new onset.