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The effects of intravenous Mexiletine (Kö1173) on cardiac performance has been studied in 20 patients affected by myocardiosclerosis (10 patients were classified in the 1st or 2nd NYHA classes, 10 cases in the 3rd or 4th ones. Mexiletine (1.5 mg/Kg) was given intravenously over a period of 1 minute. The effect on myocardial function has been evaluated by means of the systolic time intervals (STI). The drug caused non-significant changes of the left ventricular ejection time (LVET); on the contrary it caused a significant increases of the pre-ejection period (PEP), isometric contraction time (ICT) and the PEP/LVET ratio. These alteration became evident after 5--10 minutes and disappeared about 30 minutes after administration of the drug.

The antiarrhythmic action of disopyramide (1.5 mg/Kg) administered i.v. as a bolus was assessed in 30 patients with ischemic heart disease and different arrhythmias. In 75% of supraventricular parossistic tachycardia and in 75% of parossistic atrial fibrillation, arrhythmia was interrupted within few minutes from drug injection; in 90% with premature ventricular contractions (PVC) and in 100% of ventricular tachycardia, disopyramide was capable to interrupt the arrhythmias. The hemodynamic effects of the same dose of disopyramide were evaluated in other 17 patients, 9 of which in I-II class NYHA and 8 in III-IV class. We used STI's as parameters of cardiac performance. In all patients following the injection of disopyramide, a significant increase of PEP, ICT and PEP/LVET ratio and a significant decrease of LVETc were observed. Thus, the disopyramide impaired cardiac performance and its effect appeared more evident in patients in III-IV class NYHA. In conclusion, disopyramide showed to be effective in interrupting different arrhythmias; however, its depressant action on cardiac performance suggests that caution should be used in patients with severely impaired myocardial function.

The goal of this study was to identify, utilizing apexcardiogram, other noninvasive parameters useful to evaluate the functional condition of the pulmonary vascular bed in patients with mitral stenosis and insufficiency. The patients of both sexes with mitral stenosis and insufficiency underwent left and right heart catetherization and simultaneously a polygraphic study was performed. Recordings of polygraphic as well as hemodynamic parameters were performed under control condition and after 5 min breathing of 100% Oxygen administered by facial mask. These results indicate that changes in rapid filling angle have a close relationship with changes in pulmonary capillary wedge pressure and variation of rapid filling interval are correlated with changes in pulmonary capillary wedge pressure and variation of rapid filling interval are correlated with changes in cardiac output.

In this study the effects of metoprolol administration (200 mg daily per os) to 20 hypertensive subjects (WHO stage I and II), as a 20-days course, on heart rate (HR), systolic blood pressure (BP) and myocardial performance evaluated by systolic time intervals, were studied both at rest and during exercise. This treatment was able to reduce significantly HR and BP in all the patients, both at rest and during exercise. After the 20 days treatment, the left ventricular ejection time corrected for HR (LVETc) did not show any significant change both at rest and during exercise. On the other hand, the pre-ejection period (PEP) changed at rest in all the subjects studied after metoprolol treatment, but increased significantly during exercise only in patients in the I WHO class and only at the highest work load (at 70 watts, from 63 +/- 2 to 78 +/- 7 msec, P ¿ 0.05). Furthermore, in the same group of patients the maximal work load increased significantly after metoprolol treatment (from 67.5 +/- 6 to 85 +/- 8 watts, P < 0.05).