[Bradyarrhythmias (author's transl)]. / Bradykarde Rhythmusstörungen.

Bradyarrhythmias are due to disturbance of impulse formation and conduction in the heart. The sick sinus syndrome consists of both forms, sinusbradycardia being the most common type of arrhythmia, followed by sinus arrest and sinuatrial block. There is a wide range of the reported frequency of concomitant intermittent supraventricular tachycardia. Most patients have additional atrioventricular conduction disturbances. Diagnostic methods include measurement of the sinus node recovery time and sinoatrial conduction time, but therapy, i.e. pacemaker implantation depends largely on documentation of significant reduction of heart rate with clinical symptoms. The largest group of bradycardias is due to high degree atrioventricular block. As the prognosis of Mobitz Type II block is unfavorable in regard to development of complete distal av-block, differentiation between type I and II is of clinical importance, particularly in patients with additional fascicular block. Although exact localization of conduction disturbance with the Hisbundle-electrogram is possible, proof or exclusion of block distal to the Hisbundle including high frequency testing with atrial stimulation does not give the sole indication for therapeutic measures as follow up studies of patients with intraventricular conduction disturbances with and without distal block have demonstrated, that progression to complete av-block is difficult to predict.

[Results of embolectomy in massive pulmonary embolism (author's transl)]. / Ergebnisse der Embolektomie bei massiver Lungenembolie

In ten patients successful embolectomy after acute massive pulmonary embolism was performed. Clinical symptoms included circulatory arrest and shock as well as collaps, syncope and dyspnoe. Pulmonary angiography regularly showed massive, bilateral emboli. In 9 patients more than one half of the pulmonary artery system was involved (perfusion defect more than 50%). Right heart catheterization demonstrated pulmonary hypertension in all cases. In 8 patients the pulmonary artery mean pressure (PAm) exceeded 30 mm Hg. In 9 patients there were signs of right heart failure (RVEDP more than 11 mm Hg). At recatheterization 6 to 30 (mean 19) days after operation using cardiopulmonary bypass there was a marked improvement of pulmonary angiograms, which were normal in 3 cases. PAm decreased from 34.3 mm Hg to 14.6 mm Hg postoperatively and RVEDP from 14.4 to 5.1 mm Hg (p less than 0.001). These results confirm, that pulmonary embolectomy leads to a good functional results.

[Studies on the effect of Melixetin (Kö 1173) on AV-conduction time and sinus pulse automation in persons with healthy hearts and in patients with disorders of the impulse-conduction system]. / Untersuchungen über die Einwirkung von Mexiletin (Kö 1173) auf die AV-Uberleitungszeit und Sinusimpulsautomatie bei Herzgesunden und Patienten mit Erkrankung des Reizleitungs-systems

The influence of Mexiletine on the av-conduction time and sinus node recovery time of 24 patients with and without disturbance of impulse formation and conduction was examined. There was no change of conduction time proximal to the His-bundle. Four patients developed block distal to the His-bundle, 3 of which had a conduction disturbance before application of the drug consisting in 2:1 av-block or bifascicular block. Two patients with WPW-syndrome showed no change of impulse conduction. Five out of 12 patients showed an increase of the effective recovery period. Three out of 15 patients showed an increase of threshold potential from 0.35 to 0.7 volt with suppression of escape rhythm. The sinus node recovery time was prolonged in 2 out of 9 patients, one of which had a sick sinus syndrome. As there seems to be some influence of Mexiletine on sinus node impulse formation and the impulse conduction distal to the His-bundle, this drug probably should be used with caution in patients with disturbance of automaticity and distal av-conduction.

Left ventricular function after acute myocardial infarction.

10 patients with their first AMI were studied within the first 48 hours and again after 3 weeks. Central and peripheral haemodynamics (CI, SV, SW, TPR) were examined, including indices of contractility (dp/dtmax) and wall stiffness (deltaP/deltaV, relation deltaP/deltaV to P) of the left ventricle. In the early phase CI and SW, as well as LV dp/dtmax were depressed in accordance with symptoms of LV failure. deltaP/deltaV was increased. Elevation of LVEDP correlated well with ventricular gallop rhythm, but less consistently with LV functional disturbance. During convalescence CI increased uniformly, both in digitalized and non-digitalized individuals. In contrast heart rate, aortic pressure, LVEDP and dp/dtmax remained unchanged. The increase of CI, SV and SW was accompanied by a fall of TPR and deltaP/deltaV. LV wall stiffness was still elevated above normal after 3 weeks. The improvement of cardiac pumping during infarct convalescence may have been effected through a fall of TPR and LV wall stiffness. Recovery of depressed contractile performance was generally not observed, and does therefore not seem to contribute to recuperation.

[Plasma level studies of quinidine retard, their significance for dosage and onset of effect]. / Blutspiegeluntersuchungen bei Depot-Chinidin Bedentung für Dosierung und Wirkungseintritt

A new sustained-action preparation of quinidine-bisulfate (BM-Chinidin Retard) was investigated in 21 patients. After a single oral dose of 1 g peak plasma levels are reached within 3-4 hours with an unsubstantial decrease during the following 4 hours. After 2 g in three divided doses within 12 hours maximal plasma levels are found after 14-16 hours, but an effective level is reached as early as 4 hours after the first dose. With 1 g Chinidin retard given in two doses within 24 hours, varying plasma concentrations are reached after 24 hours, reaching a maximum after 48 hours and decreasing to a medium level thereafter. The minimal concentrations measured were 23 percent lower than the maximal concentrations suggesting that during longterm application rather stable plasma levels are achieved. The effectiveness of the preparation was demonstrated in patients with atrial fibrillation and flutter, supra-ventricular and ventricular premature beats. Longterm treatment was attempted in all patients. Quinidine effectiveness and plasma concentrations were constant throughout the observation period. Side effects were rare: inappetence, vertigo, and headache were observed transiently in 4 patients without necessitating a change in medication. ECG-alterations occurred as described for quinidine-prepartions in general.

[Antiarrhythmic treatment of ventricular ectropic arrhythmies with Disopyramide]. / Antiarrhythmische Terapie mit Disopyramid bei ventrikulären Extrasystolen

Disopyramide (D.) is a new antiarrhythmic agent, which is not related chemically to any of the known substances. Animal experiments have shown a close similarity to quinidine action. Side effects are mainly due to anticholinergic effects. Pharmacokinetic studies with radioactive labelled D. have demonstrated that 80 per cent are elimated via the kidneys and 15 per cent through the gut. Gastrointestinal reabsorption in 90 per cent. We have studied the antiarrhythmic properties of D. in ventricular ectopic arrhythmias in twenty male patients. There were 13 myocardial infarctions, 5 cardiomyopathies, one severe oartic regurgitation with prosthetic valve replacement, one case with VPB of unknown aetiology. In ten cases the influence of D. on ventricular excitation threshold in implanted pacemakers was studied. The effects were correlated with Disopyramide-plasma levels. D. was effective in suppressing VPB. It was successful in 67 per cent, in 30 per cent the effect was unsatisfactory. Pacemaker-threshold remained unaltered. Side effects included constipation. Two deaths were observed. Their relationship to the adminstration of D. is not definitely proved. Nevertheless should the drug because of its negative inotropic action be employed with caution in cases with congestive heart failure.

Effect of diazoxide on left ventricular performance in hypertension.

The effect of diazoxide on left ventricular performance during rest and isometric exercise (handgrip) was examined in 16 unselected hypertensive patients, 6 of whom had been pretreated with the beta-adrenergic blocking agent pindolol. Diazoxide regularly and promptly produced a fall in left ventricle systolic and end diastolic pressures, and an increase in heart rate and left ventricular dp/dtmax. Haemodynamic changes were maximal 2 minutes after injection of the drug and decreased little over the next 8 minutes. After beta-adrenergic blockade, diazoxide caused a more pronounced reduction in left ventricular systolic pressure and a less marked fall in end-diastolic pressure, whilst the diazoxide-induced rise in heart rate was partially and the increase of dp/dtmax was completly inhibited. The increase in systolic pressure during isometric exercise was not influenced by diazoxide, but the positive inotropic reaction was augmented. The findings appear to show that cardiac stimulation by diazoxide is due to a reflex mechanism transmitted by baroreceptors, and that improvement of cardiac performance is mainly due to a reduction of left ventricular after-load.

[Corrected transposition of great vessels in adult age]. / Korrigierte Transposition der grossen Gefässe im Erwachsenenalter

Two adult cases of corrected transposition of the great arteries are presented. One of the two males had associated ventricular septal defect, the other one presented as an isolated anomaly. The characteristic clinical features are: loud second heart sound with audible pulmonic component of the left sternal border in the absence of pulmonary hypertension. Abnormal precordial impulse upon palpation. Chest X-ray shows absence of pulmonic segment and of the aortic knob with the contour of the ascending aorta to the left of the mediastinum. Ecg anomalies may be multiple; typically anomalous septal Q-waves are consistently absent. Corrected transposition is well tolerated even into adulthood. Prognosis is dominated by assiciated anomalies.