PubMed Health⌕ Search

Biomedical subjects

S F Schaal

Publications and source records attributed to S F Schaal.

At least 73 records · Page 4Linked to original sources
PubMed1977

Negative inotropic effect of lidocaine in patients with coronary arterial disease and normal subjects.

The effect of administration of lidocaine on left ventricular performance was studied using systolic time intervals in nine normal subjects, eight patients with stable angina, and 15 patients with acute myocardial infarction. The greatest response in systolic time intervals occurred at three minutes after intravenous injection of lidocaine (100 mg), with values returning to baseline at 10 to 15 minutes. Administration of lidocaine produced a significant prolongation of the preejection period (PEP) corrected for heart rate in all groups and a prolongation of the ratio of PEP to left ventricular ejection time (PEP/LVET) in patients with angina. The group with acute myocardial infarction exhibited a hyperadrenergic state, as shown by a short baseline QS2I. The QS I was lengthened by administration of lidocaine in all groups, but this was more profound in those with acute myocardial infarction. These changes in systolic time intervals were still present at two hours after injection in six patients with acute myocardial infarction in whom an infusion of lidocaine followed the initial bolus. The effect of administering lidocaine after intravenous injection of propranolol (5 mg) was also studied in six normal subjects. Although propranolol therapy along prolonged the PEP/LVET, a further significant prolongation followed subsequent injection of lidocaine.

Acute Disease↗
PubMed1976

First-degree sinoatrial heart block: sinoatrial block in the sick-sinus syndrome.

Sinoatrial conduction time (SACT) was estimated from the delay in the atrial recovery period after premature depolarization applied in that portion of atrial diastole when increasing prematurity resulted in a constant recovery interval. In 20 normal patients SACT was 169 msec. +/- 91 (2 S.D.). At least nine of 19 patients with "sick-sinus syndrome" (SSS) demonstrated SACT that were longer than seen in these normal subjects. SACT was prolonged in seven of nine SSS patients with abnormal A-V nodal conduction. Among 10 SSS patients with normal A-V conduction, only two had prolonged SACT. This study identifies first-degree sinoatrial block as a frequent manifestation of SSS associated with the presence of A-V node conduction abnormalities.

Arrhythmia, Sinus↗
PubMedDate not supplied

Effect of cimetidine on quinidine bioavailability.

Elevations in quinidine steady-state serum concentrations have been reported in patients who received cimetidine concurrently. Studies in normal volunteers have shown that areas under the serum concentration-time curve of orally administered quinidine are higher when quinidine is given during chronic cimetidine therapy as compared to under control conditions. The mechanism for this interaction is generally ascribed to decreased hepatic clearance as a consequence of enzyme inhibition. In this study, we show that cimetidine also decreases the bioavailable fraction of quinidine.

Administration, Oral↗
PubMedDate not supplied

Effects of commonly used cardioactive drugs on atrial and sinoatrial conduction in man.

Atrial and sinoatrial conduction intervals were measured in patients before and after the intravenous administration of one of four cardioactive drugs: procainamide, atropine, ouabain, and propranolol. Procainamide uniformly prolonged atrial conduction and shortened sinoatrial conduction. Atropine also shortened sinoatrial conduction but did not significantly alter atrial conduction. Ouabain prolonged sinoatrial conduction in patients with normal control sinoatrial conduction intervals and did not affect atrial conduction. Propranolol did not significantly alter sinoartrial conduction and only prolonged interatrial conduction in patients with normal base line atrial conduction intervals. Of the cardioactive drugs tested, only procainamide and propranolol significantly altered the atrial conduction intervals; furthermore, the effects of these cardioactive drugs on sinoatrial conduction were disparate from their effects on atrial conduction.

Adult↗
PubMedDate not supplied

Electrophysiologic and antiarrhythmic effects of nitroglycerin in man.

The electrophysiologic properties and the arrhythmic disposition of the human heart were determined in 16 patients before and after the intravenous administration of nitroglycerin (0.25 and 0.50 micrograms/kg/min). At the higher dose, nitroglycerin significantly shortened the atrial and ventricular effective refractory periods and bundle of His-Purkinje conduction (HV interval). Otherwise, a paucity of general electrophysiologic effects was noted; atrial conduction intervals were not altered, and although a trend toward shortening occurred, the sinus node function studies (conduction and recovery times) and atrioventricular nodal conduction did not change significantly with nitroglycerin. Nitroglycerin demonstrated antiarrhythmic properties; the ventricular echo zone and the number of ventricular echo-repetitive ventricular response beats following ventricular stimulation decreased significantly with nitroglycerin. Nitroglycerin ameliorated the tendency toward sustained repetitive ventricular response in 4 of 5 patients and obliterated the development of this tachyarrhythmia in 1. Although the precise mechanisms were not delineated by this study, it is clear, that nitroglycerin causes some change in the electrophysiologic properties of the human heart and that it appears to have (or elicit) beneficial antiarrhythmic effects.

Adult↗