Intracardiac Shunt-Use of the Hydrogen-Sensitive Catheter to Clarify False Positive Diagnosis of Left-to-Right Shunt.

The charts of 142 patients who had diagnostic right heart catheterization with conventional oximetry, oxygen content determinations and hydrogen electrode curve recording for left-to-right shunt were reviewed. A false positive diagnosis of surgical significance would have been made in nine patients if the hydrogen electrode had not been used. In addition, a diagnosis of left-to-right shunt could have been made at the wrong chamber level in three additional cases.

Electrical cardioversion-effectiveness of quinidine prophylaxis following countershock.

Direct current countershock was given to 46 patients with chronic atrial fibrillation of diverse causes, with successful conversion in 87 per cent of them. Patients were observed while receiving quinidine prophylaxis, with serial determination of serum quinidine levels, for up to 22 months. Two quinidine preparations were employed, one a long-acting form, in various dosage regimens and both preparations were found to be effective prophylactic agents for maintaining reliable serum quinidine levels. Fifty per cent of patients remained in normal sinus rhythm at three months, 28 per cent at six months and 13 per cent at twelve months.