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Biomedical subjects

R Stroobandt

Publications and source records attributed to R Stroobandt.

At least 37 records · Page 2Linked to original sources
PubMed1986

Prediction of Wenckebach behavior and block response in DDD pacemakers.

At higher atrial rates, the behavior of a DDD pulse generator will depend on the atrial rate or spontaneous atrial interval (SAI) and the settings of the pacemaker: upper rate interval (URI), atrioventricular interval (AVI), and atrial refractory interval (ARI). An algorithm was developed enabling the prediction of the degree of Wenckebach block using the parameters mentioned above. In the absence of the programmed settings of the pacemaker, these parameters can be determined by noninvasive methods. AVI can be measured by application of a magnet over the pulse generator, while URI and ARI can be estimated during chest wall stimulation by progressively increasing the frequency of the external extrastimuli. The use of the formula in combination with chest wall stimulation allows the evaluation of the proper functioning of any DDD pacemaker during exercise and in patients with atrial rhythm disturbances, even when no information about the pacemaker settings is available.

Atrioventricular Node↗
PubMed1985

Simultaneous recording of atrial and ventricular monophasic action potentials: monophasic action potential duration during atrial pacing, ventricular pacing, and ventricular fibrillation.

A newly developed transvenous suction electrode was used in dogs to record monophasic action potentials (MAPs) from the right atrium and right ventricle simultaneously. Continuous MAP recordings could be made from the same endocardial site for test periods of 1.5 hours. Left ventricular pacing at increasing heart rates resulted in a statistically significant decrease of right ventricular MAP duration. A high degree of correlation was found between right ventricular MAP duration at 90% of repolarization and the QT interval during both right atrial and left ventricular pacing. At the onset of ventricular fibrillation (VF), right ventricular MAP duration shortened to 25% of the value obtained during left ventricular pacing at a cycle length of 250 ms. A cyclic alternation in amplitude of the right ventricular MAPs was observed during VF. Fast Fourier Transform Analysis of right ventricular MAPs during VF showed a significant dominant frequency at 12 Hz, with no levels of interest beyond this frequency. This observation might prove to be useful in elaborating a new algorithm for the automatic detection of ventricular fibrillation.

Action Potentials↗
PubMed1985

Efficacy and tolerance of intravenous lorcainide in patients with normal and impaired intraventricular conduction.

The effectiveness and safety of intravenous lorcainide was evaluated in 14 patients with normal (QRS less than 110 ms) and in 9 patients with prolonged QRS duration (QRS greater than or equal to 110 ms) showing chronic high frequency premature ventricular complexes (mean value of PVCs 17 min-1). Lorcainide was infused intravenously by intermittent bolus at 10 mg every minute to a total dose of 160 mg with exception of 5 patients with a prolonged QRS duration who only received 100 mg. The overall reduction of PVCs 1 hour after administration of the drug was 86% (p less than 0.05) in the patients with normal QRS duration and 98.5% (p less than 0.05) in the patients with a prolonged QRS duration. The mean plasma drug level achieved 1 h after treatment was 280 +/- 60 ng/ml in the patients with QRS less than 110 ms and 170 +/- 40 ng/ml in the patients with a QRS greater than or equal to 110 ms. Heart rate and blood pressure did not change but a significant increase (p less than 0.05) in QRS duration (+37%) was observed 30 min after the infusion of 160 mg lorcainide in the patient group with normal QRS duration. Lorcainide was well tolerated. Mild adverse effects were observed in five patients including: warmth sensation, vomiting, paresthesias, transient hypotension and the development of a junctional escape rhythm. Therefore lorcainide appears to be a safe and effective drug, that can even be administered to patients with a prolonged QRS duration.

Adult↗
PubMed1984

Efficacy and tolerance of intravenous flecainide in patients with chronic high frequency ventricular arrhythmias.

The effectiveness and safety of intravenous flecainide was evaluated in 33 patients with chronic high frequency premature ventricular complexes (mean value of PVCs 23.7 min-1). Flecainide was injected intravenously at a rate of 20 mg per 2 min until complete disappearance of ventricular arrhythmias or up to a total dose not exceeding 200 mg. Total suppression of PVCs occurred in 31 out of 33 patients at the end of the injection (mean dose 132 mg). The overall reduction of PVCs was 94 per cent (P less than 0.001) at the end of infusion and 74 per cent (P less than 0.001) 1 h later. The mean plasma drug level attained 1 h after administration was 287 ng ml-1 (range 82-984). Heart rate and blood pressure did not change, but a significant increase (P less than 0.001) in PR (+12%), QRS (+13%) and QTc (+4%) duration occurred after drug administration. Flecainide was well tolerated. An idioventricular tachycardia was induced in one patient and two patients experienced side effects of the central nervous type: dizziness, blurring of vision and a sensation of warmth. In view of its activity flecainide appears to be a valuable addition to the antiarrhythmic armamentarium.

Adult↗
PubMed1984

Dose related efficacy of betaxolol in combination with nitroglycerin in patients with angina pectoris: a double blind cross-over study.

The effect of three different oral doses, 5 mg, 10 mg and 20 mg of betaxolol (BTX), a new long acting cardioselective beta-adrenergic blocking drug, on exercise tolerance was studied in a randomized double blind, cross-over study with latin square distribution in nine male patients with angina pectoris, under continuous therapy with oral nitroglycerin. BTX caused a significant reduction of heart rate (p less than 0.001) for all different dose levels during exercise. Systolic blood pressure was significantly decreased at peak exercise for BTX 10 (p less than 0.01) and BTX 20 (p less than 0.001). During the three treatment periods a significant drop of the rate pressure product (p less than 0.01) was observed and a statistically significant improvement of exercise tolerance, before the occurrence of anginal pain, could be demonstrated. No differences could be detected in oxygen uptake, carbon dioxide output and ventilation between placebo- and treatment periods. BTX was well tolerated in all patients and exerted its effect also in the presence of nitroglycerin. Its cardioselectivity, ease of dosing and complete absence of side effects makes BTX an attractive choice as antianginal agent for chronic use.

Adrenergic beta-Antagonists↗
PubMed1983

Efficacy of intravenous sotalol on ventricular arrhythmias occurring during maximal exercise stress testing.

The efficacy and safety of an intravenous dose of 40 to 100 mg sotalol was evaluated in fourteen symptomatic patients with ventricular arrhythmias occurring during maximal exercise stress testing. A statistically significant reduction in premature ventricular complexes (PVC's) occurring as singles, doublets and triplets was observed during both exercise (p less than 0.05) and recovery (p less than 0.01). Sotalol plasma levels after administration of 100 mg i.v. ranged from 3.7 to 4.75 micrograms/ml (average 4.2 micrograms/ml). The injected dose was well tolerated in all patients. Neither arrhythmogenic nor adverse effects were observed.

Adolescent↗
PubMed1982

Clinical efficacy of torasemide, a new diuretic agent, in patients with acute heart failure: a double blind comparison with furosemide.

Torasemide 60 mg and furosemide 120 mg were administered intravenously in a randomized double blind study in twelve patients with acute heart failure. The action of both drugs on urinary electrolyte and water excretion was very similar. The administration of torasemide but not of furosemide resulted in a significant reduction of systolic and diastolic blood pressure. No side effects occurred with either of the drugs in this elderly patient group.

Adult↗
PubMed1982

Reproducibility of exercise-induced ventricular premature beats.

Repeated maximum exercise testing with an intertest interval of one hour is a valid model for testing drug efficacy and safety on ventricular arrhythmias occurring during exercise. In the two consecutive exercise tests the mean total number of VES was 182 and 184 respectively and the slope of the regression equation relating both tests was close to unity.

Adult↗
PubMed1981

Intravenous metoprolol for the treatment of acute supraventricular tachyarrhythmias.

The antiarrhythmic effect of the cardioselective beta-adrenoreceptor blocking agent metoprolol, given intravenously, was studied in 20 patients with acute supraventricular tachyarrhythmias, including patients with congestive heart failure, acute myocardial infarction and complete bundle branch block. Six patients out of 9 with atrial fibrillation reverted to sinus rhythm. In all patients with atrial tachycardia and 3 out of 4 patients with atrial flutter restoration of sinus rhythm occurred. The drug was well tolerated and is of clinical value for the treatment of supraventricular tachyarrhythmias even in an elderly patient group.

Aged↗
PubMed1980

Potential causes of spurious programming: report of a case.

The possibility of false or inadvertent reprogramming increases with the availability of different and more complex programming mechanisms. A case of spurious programming during application of the Vitatron MPA1 analyzer to a Medtronic impulse generator (IPG) is described and the nature of the phenomenon is explained. It is concluded that the introduction of a simple and standardized "security-maneuvre" to which every IPG will respond safely, in the event of fortuitous dysprogramming, is required.

Aged↗
PubMed1979

Clinical experience of encainide (MJ 9067): a new anti-arrhythmic drug.

Encainide is a new anti-arrhythmic drug, which is highly effective against ventricular extrasystoles, both single and coupled, in the dose range of 80--140 mg i.v. Ventricular extrasystoles were abolished in 31 out of 33 cases treated. The drug is also relatively effective against supraventricular extrasystoles, but has little effect on atrial fibrillation. Both subjects with clinically normal hearts and those with ischaemic heart disease have been successfully treated. The drug prolongs the QRS and QT duration. Its effectiveness appears to be of the same order of magnitude and the range of indications similar to those of aprindine and lorcainide. Further study of the drug seems to be warranted.

Anilides↗
PubMed1977

Clinical experience with lorcainide (R 15 889), a new anti-arrhythmic drug.

The anti-arrhythmic properties of a new drug, lorcainide, have been evaluated. Lorcainide is highly efficient for the treatment of ventricular arrhythmias, especially ventricular extrasystoles and recurrent ventricular tachycardia. It is also efficient in the treatment of supraventricular extrasystoles and repetitive auricular tachycardia. It is ineffective in cases of auricular fibrillation and flutter. The drug also has effective anti-arrhythmic properties when administered orally. It has a small negative inotropic effect which was not clinically relevant in the patient group studied. Side effects were within acceptable limits and essentially consist of dizziness, tremor and blurring of vision, occurring only during rapid i.v. injection and depending upon the speed of injection.

Acetamides↗
PubMed1976

Anomalous coronary arterial pattern.

The clinical history of an adult patient with anginal-like pain is described. A coronary angiography revealed the existence of a hypoplastic left coronary artery, a right coronary artery which passed around the posterior surface of the heart and continued into the anterior surface of the heart to give off an anterior descending artery and the presence of a "conus" artery. The embryonic genesis of hypoplastic coronary artery and of a similar aberration, single coronary artery, are discussed.

Angiography↗
PubMed1975

Hypertrophic non-obstructive cardiomyopathy caused by disorder of the myofiber texture.

A case of hypertrophic non-obstructive cardiomyopathy caused by a disorder of the myofiber texture was observed in a 10 year old boy. The heart weighed 390 g and showed concentric hypertrophy of the left and right ventricles as well as of the ventricular septum. Additional findings consisted in an abnormal septum membranaceum and a accessory tricuspid valve leaflet. Severe cardiac hypertrophy was associated with prominent interstitial and subendocardial fibrosis, and pronounced intimal fibrosis of the intramural arteries. Electron microscopy revealed various degrees and stages of hypertrophy of the myocardial cells combined with severe degenerative changes. Additional changes of the sinus node and conduction system were responsible for a tachycardia-bradycardia syndrome, complete left bundle branch block and final total AV-block.

Autopsy↗