Double atrial parasystole. Case report.

A 62 year-old man with hiatal hernia and complex atrial arrhythmia is reported. On the standard electrocardiogram a double atrial parasystole is found, with reversed coupling. During carotid sinus massage only one of the parasystolic foci is not influenced, and assumes the atrial activity, regularizing the cardiac rhythm.

Cardioversion of atrial fibrillation to sinus rhythm using quinidine given in rapid administration.

A rapid method using quinidine sulphate for the cardioversion of atrial fibrillation is presented. Intensive administration of the drug allows the use of lower doses (mean dose 1.159 g quinidine sulphate), with high convertibility rate (69.76%); 7 hours after the start of the procedure 94 per cent of the patients were already in sinus rhythm. The short duration of this procedure allows careful monitorization of the patients.

Ventricular pacing as a bedside method in the treatment of ventricular tachycardia.

In five patients with drug resistant ventricular tachycardia (VT) seven successful ventricular pacings were performed, using a bedside technique. The ventricular stimulation was always started with underdrive pacing, and in case of no result, continued with overdrive pacing. In two cases the underdrive pacing was successful, and in four cases only the overdrive pacing achieved suppression of tachycardia.

Parasystolic ventricular tachycardias in young healthy patients.

Seven patients with short episodes of parasystolic ventricular tachycardia, in the absence of organic heart disease, and in good healthy state, are presented. The tachycardic episodes were analyzed through simultaneous esophageal and standard electrocardiographic recordings. The persistent fetal dispersion of nodal and Hiss bundle fragments within the ventricular septum is proposed as a possible explanation.

First degree atrioventricular block with periodic variations in conduction time.

Periodic variations in PR interval from 0.16 sec to 0.36 sec is discussed in a patient without overt cardiac disease. The unequally blockage of slow and fast pathways within the A-V node is proposed as explanation of the phenomenon.

Role of ketanserin in the treatment of the essential arterial hypertension associated with ischemic heart disease.

This clinical study was set-up to evaluate the antihypertensive effect of ketanserin in essential hypertension (EH) associated with asymptomatic ischemic heart disease (IHD) in twenty-seven patients. Every patient received 20-40 mg ketanserin, a selective S2 serotoninergic antagonist, twice daily, for a three-month period. The blood pressure (BP) was significantly lowered during the treatment with ketanserin, much more in female patients and elderly group.

The residual myocardial contractile reserve in the rational use of digitalis.

A simple noninvasive method for the estimation of residual myocardial contractile reserve by using the postextrasystolic stimulation and systolic time intervals is proposed. The rational use of digitalis, avoiding the toxic effects, is possible only if the presence or absence of the residual contractile reserve is taken into consideration.

Digitalis, a defibrillatory drug.

Digitalis glycosides have an antiarrhythmic effect in atrial fibrillation, as defibrillatory drugs. These drugs could be classified in a group of antiarrhythmic drugs close to the ventricular defibrillating drugs recently proposed. The reasons for this opinion are shown in this work.

[Effects of lidocaine on supraventricular arrhythmias (author's transl)]. / Effetti della lidocaina nelle aritmie sopraventricolari

Using Lidocaine intravenously in 99 patients with atrial arrhythmias, it was observed that the drug has a regularising effect in 41 from 45 atrial arrhythmia, atrial tachycardia with block and accelerated ectopic supraventricular tachycardia, where the enhanced focal activity should be taken into account. No effect was observed in functional supraventricular tachycardia, paroxysmal atrial flutter and fibrillation and tachyarrhythmia in WPW syndrome, where the re-entry mechanism plays the major role. The effect of the drug is short lived, but may be prolonged by using the drug in perfusion or repeatedly with an intramuscular method. Lidocaine acts by depressing the enhanced atrial focal activity, and therefore may be of value in the treatment of these kinds of arrhythmias.

Emergency situations in sinus node dysfunction.

Sinus node dysfunction may produce in some cases life threatening medical emergencies. From 138 patients with sinus node dysfunction followed up in our department, we present 8 cases in which emergency situations required special therapeutical approaches (precordial thump, atrial or ventricular pacing, permanent pacemaker implantation). These situations appeared spontaneously, during the investigation procedures or after conversion of atrial fibrillation, performed for therapeutic purposes, when this arrhythmia concealed a sinus node dysfunction. The tachy-brady-arrhythmia could be influenced only by the implantation of a permanent pacemaker.

Peculiar atrial fibrillation in patients working with electric current.

During a period of 20 years, 8 patients with atrial fibrillation, without other cardiac abnormalities, resistant to electroconversion, but successfully defibrillated with quinidine, were examined. All were males, aged 40 to 50 years, working with electric current and exposed for many years to frequent electric shocks. The authors consider that chronic exposure to electric current induces a special form of atrial fibrillation, resistant to electric conversion. The inefficiency of the electroshock therapy in such cases might be explained by the increase of transthoracic impedance consecutive to repeated electrocutions.

Intermittent concealed atrial conduction demonstrated through intracavitary leads.

An intermittent vanishing of the P wave from a standard electrocardiogram (ECG) while normal atrial activity was recorded on intracavitary leads was observed in a 58 year old man. This intermittent concealed atrial conduction is discussed.

An attempt to localize the accessory pathway in WPW syndrome using electrocardiographic methods.

In fifteen patients with WPW syndrome the standard electrocardiogram, the vector cardiogram and the precordial map were used togther in order to better localize the ventricular pre-excitation. These three noninvasive techniques permit a more precise location of the accessory pathway in WPW syndrome.

Postextrasystolic changes in ventricular depolarization (electrocardiographic observations).

Postextrasystolic changes in ventricular depolarization were found in patients with coronary artery disease in two situations: a) after a compensatory postextrasystolic pause and, b) after an interpolated ventricular beat. The explanation and the underlying conditions of this phenomenon are discussed. In our opinion the postextrasystolic change may be a silent myocardial ischemia.

Analysis of human atrial fibrillatory waves using monophasic action potential technique.

In 29 patients with atrial fibrillation, using the monophasic action potential technique, the fibrillatory waves were recorded and analyzed by statistical methods. Concerning the characteristics of the fibrillatory waves there are no differences between patients with rheumatic heart disease and with coronary heart disease. The patients with paroxysmal forms and those without heart failure and with normal heart size, have similar statistical data with regard to their fibrillatory waves. From the data presented, it could be possible to predict the efficacy of conversion to sinus rhythm and also the sinus rhythm stability after conversion.

Atrio-ventricular conduction disturbances occurring after strenuous physical effort.

Two young patients with a-v conduction disturbances occurring in relation with strenuous physical effort are presented. The possible mechanism may be an excessive vagal tone.

The efficacy of sublingual verapamil in controlling rapid ventricular rate in chronic atrial fibrillation.

The efficacy of sublingual verapamil (Verapabene, 40 mg) in acute control of high ventricular rate was assessed in 20 patients with chronic atrial fibrillation (AF) of ischemic origin (class NYHA II and III). The effect on irregularity of the rhythm was also studied using time domain parameters of heart rate variability. Four ECG recordings (before, and at 10, 30 and 60 minutes after the administration), of 10 minutes each, were performed in every patient in basal conditions. The parameters were compared using paired t-test and Wilcoxon's test. Mean heart rate became significantly lower (p = 0.0064) after 10 minutes, and reached progressively the lowest value after 60 minutes (from the initial 112.9 beats/min to 90.6 beats/min, after 60 minutes, p < 0.0001). The irregularity parameters (SDNN--from 114.7 ms to 148.6 ms, rMSSD--from 152 ms to 205.9 ms) and the NNmin interval (from 353 ms to 404.5 ms) increased significantly after 30 and 60 minutes (p < 0.0001), but the frequency corrected irregularity (coefficient of variability) remained unchanged (p > 0.4). Sublingually administered verapamil proved to be an efficient alternative in acute control of rapid ventricular rate in AF. The method has the advantage to be applicable by a properly instructed patient itself.

The monophasic action potential: a simple in vivo model to evaluate the effects of antiarrhythmic drugs at atrial level.

Monophasic action potential (MAP) represents an extracellular recording of electrical potentials variations produced simultaneously by several cells. Even if it does not represent the real cellular action potential, monophasic action potential generally reproduces with accuracy that aspect, being useful especially in the assessment of myocardial repolarisation phases. Monophasic action potential recording was performed with a quadripolar catheter designed by Franz; the quality of recordings was good and the procedure is safe. In clinical electrophysiology, monophasic action potential may be helpful in the study of certain aspects that cannot be evaluated adequately by standard electrophysiological techniques. The study was performed on six patients, in drug-free state. The duration of monophasic action potential at 90% of repolarisation and the atrial effective refractory period, at three basic cycle lengths (600, 500 and 400 msec) were determined. Both monophasic action potential duration at 90% of repolarisation and the atrial effective refractory period shortening at short cycle length and a linear correlation between these two parameters were seen. We conclude that the correlation between monophasic action potential duration and the effective atrial refractory period may be a simple and useful model to characterise in vivo the electrophysiologic profile of antiarrhythmic drugs.

Complex atrial arrhythmias studied by suction electrode technique.

Two elderly patients with coronary heart disease, chronic pulmonary disease, and complex atrial arrhythmias are presented. The suction electrode technique for right atrium monophasic action potential recording was used. This recording allows better analysis of the atrial arrhythmias and estimates the stability of focal activity.