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Biomedical subjects

M Condorelli

Publications and source records attributed to M Condorelli.

At least 289 records · Page 16Linked to original sources

Hemodynamic response to exercise after propranolol in patients with mitral stenosis.

Hemodynamic response to exercise before and 10 minutes after propranolol (5 mg intravenously) was studied in 10 young patients with pure mitral stenosis who had normal sinus rhythm and no cardiac failure. After propranolol the mean heart rate and cardiac index at rest were lower than during the control state (respectively, 95 +/- 4 versus 82 +/- 3 beats/min, P less than 0.005; 3.4 +/- 0.2 versus 2.8 +/- 0.1 liters/min per m2, P less than 0.025). As a result, the mean pulmonary wedge pressure and mean mitral valve gradient at rest were lower (respectively, 22 +/- 2 versus 18 +/- 2 mm Hg, P less than 0.005; 24 +/- 2 versus 17 +/- 2 mm Hg, P less than 0.001). During exercise after propranolol the values of pulmonary wedge pressure and mitral valve gradient were lower than control values during exercise (respectively, 39 +/- 3 versus 30 +/- 2 mm Hg, P less than 0.005; 44 +/- 3 versus 32 +/- 3 mm Hg, P less than 0.005), again because of the lower heart rate and cardiac index (130 +/- 6 versus 104 +/- 6 beats/min, P less than 0.001; 4.6 +/- 3 versus 3.7 +/- 2 liters/min per m2, P less than 0.01). Left ventricular end-diastolic pressure and stroke index showed no significant changes. Thus, propranolol may benefit patients with pure mitral stenosis with sinus rhythm and no cardiac failure whose symptoms occur during those reversible conditions characterized by an increase in heart rate or cardiac output, or both.

Adult↗

Automatic "scanning" by radiofrequency in the long-term electrical treatment of arrhythmias.

The use of programmed electrical stimulation in the long term treatment of re-entry tachycardia offers encouraging perspectives. Among the others proposed, the "scanning" system seems to be the most effective. However, an implantable stimulator with these features is not yet available and, thus, a temporary external lead is required. These difficulties have been overcome by utilizing radiofrequency to synchronize and stimulate. An implantable device was therefore designed which is triggered by the patient and automatically searches the interruption zone of the tachycardia by exploring the R-R cycle. The external transmitter, which can produce one or two synchronized impulses, is programmed to scan the R-R cycle with progressive steps of 5 or 10 ms; when tachycardia is interrupted, further stimulation is inhibited. The implanted module connected to an endocavitary lead does not have any power supply and, therefore, is very small. The efficacy of this method has been demonstrated in 4 patients with supraventricular tachycardia (3 with WPW syndrome) resistant to conventional pharmacologic therapy.

Chronic Disease↗

Protective effects of propranolol on the exercise-induced reduction of blood flow in arteriopathic patients.

The vascular steal phenomenow, that is, the shunting of blood from ischemic to normally perfused areas, is commonly observed during exercise in the affected limbs of patients with peripheral arterial insufficiency. Propranolol was administered to 18 arteriopathic patients before the exercise to ascertain whether the reverse situation can be induced. The results indicate that before propranolol administration, Jantsch's index (used to quantify the plethysmographic waves) decreased from 0.53 +/- 0.05 to 0.33 +/- 0.04 (P less than 0.001) at 1 minute, and to 0.38 +/- 0.04 (P less than 0.001) at 5 minutes after the end of the exercise. When the exercise was repeated after propranolol, Jantsch's index did not change. These findings indicate that propranolol can inhibit exercise-induced vascular steal.

Arterial Occlusive Diseases↗

[The effects of intravenous mexiletine on cardiac performance (author's transl)].

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.

Adult↗

[Clinical and hemodynamic effects of disopyramide phosphate administered i.v. in cardiopathic subjects (author's transl)].

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.

Adult↗

[Short-term and average-term automatic control of re-entry arrhythmias].

The AA. described an external stimulator to be utilized instead of invasive pharmacological treatment, as a short and middle-time therapeutic approach to re-entry tachycardia, in Departments of cardiology. The device must be connected with an electrode placed in atrium or in coronary sinus or in ventricle, according to individual request. A frequency discriminant device recognizes tachycardia and activates automatic scanning stimulator, synchronized on R or P waves, with progressive 5 msec stop delay; tachycardia interruption zone is automatically individuated. Stimulation has an automatic stop when tachycardia is interrupted; in case of persistent tachycardia scanning-function cycle will star again automatically. The device, which can be programmed for a simple or a double impulse emission, is equipped with a demand stimulator working if post-tachycardia asystole is present. Frequency discriminant device activates the scanning function beyond a defined threshold which can be varied within a wide range of frequencies.

Arrhythmias, Cardiac↗

[Echocardiographic size of the left atrium and pulmonary "capillary" pressure in different cardiopathies].

In order to investigate the relationship between left atrial pressure and volume, left atrial echograms and mean pulmonary wedge pressure were obtained on 64 patients with various cardiac diseases. A statistically significant relationship was found in the whole group (r = 0.67, p < 0.01), but there was a considerable degree of dispersion around the regression line. A good correlation was present in 6 patients with hypertrophic cardiomyopathy (r = 0.97, p < 0.01) and in 13 patients with long standing mitral valve disease (r = 0.85, p < 0.01). There was no correlation in coronary artery disease patients.

Adolescent↗