Clinical antiarrhythmic efficacy of mexiletine: a review.

This paper consists of a review of some of the most important papers which have recently been devoted to mexiletine. The electrophysiological effects of the drug in normal subjects and in patients with abnormal impulse formation or conduction are described. The results of open studies related to the clinical effects of mexiletine administered intravenously or orally are briefly reported.

The efficacy of intravenous moxaprindine on ventricular ectopic activity.

Moxaprindine, a new derivative of aprindine, has been showed to possess strong antiarrhythmic properties in the dog. It is significantly less toxic than aprindine on hematopoietic cells in culture. This drug was given intravenously (2 mg/kg given over a 30 min period), to 10 patients with severe, refractory and symptomatic ventricular arrhythmias.

[Hemodynamic complication of ventricular stimulation in a patient with moderate aortic stenosis].

This report is concerned with a patient aged 76 with mild to moderate aortic stenosis and transient A-V block who was treated by stand-by intracardiac pacing. In spite of this, the patient continued to present syncopal attacks. It is demonstrated that these episodes were related to dramatic decreases of systolic blood pressure and cardiac output occurring whenever the right ventricle was paced.

Histopathologic correlates of left posterior fascicular block.

Thirteen hearts from subjects (10 male, 3 female; mean age 65 years) with left posterior fascicular block were studied. Left posterior fascicular block was associated with right bundle branch block in nine cases and alternated with left anterior fascicular block in three. In nine of the patients, the conduction disorders were observed during an episode of acute myocardial infarction.

Electrophysiological effects of L 9394 (benzoyl-indolizine) in man.

The electrophysiological effects of L 9394 (benzoyl-indolizine), a substance chemically related to amiodarone, but devoid of iodine atoms, were investigated by programmed electrical stimulation of the heart in 12 patients with various forms of tachycardia. Four subjects had electrocardiographic evidence of the WPW syndrome and episodes of circus movement tachycardia. Paroxysmal supraventricular tachycardia, confined to the atrioventricular (AV) node, was found in 3 patients.

Histopathological correlates of sinoatrial disease.

Six hearts from patients suffering from rhythm disorders consistent with the diagnosis of sinoatrial disease were histologically examined. Four of the patients had shown a tachycardia-bradycardia syndrome, and the remaining two patients episodes of sinus arrest or sinoatrial block with a slow junctional escape rhythm. The rhythm disorders had occurred in the setting of chronic sinoatrial disease (3 cases), acute myocardial infarction (2 cases), and diphtheritic myocarditis (1 case).

Advances in the understanding of conduction disturbances.

The interest towards intraventricular conduction defects started some 10 yr after the introduction of the string galvanometer by Einthoven. As early as 1910, it was known that conduction blockade could occur along either branch of the intraventricular conducting pathway. It took some 20 yr to identify properly the electrocardiographic manifestations of right and left bundle branch blocks.

Model studies on activation of the heart.

Multiple dipole models of activation of the heart, in combination with a model of the thorax as an electrical conductor relate the action of individual cells to features of the electrocardiogram. The models can be used to develop diagnostic electrocardiographic criteria for ventricular hypertrophy, myocardial infarction or conduction disorders. Criteria derived with the use of Holt, Barnard and Lynn's model proved to be superior to well-established empirical rules.

Experience with a community screening program for hypertension: results on 24,462 individuals.

A hypertension screening program was conducted by means of mobile units generally used for detection of tuberculosis and chest diseases. From 1st October 1973 to 31st July 1976, 24, 462 individuals aged 35 and over were examined. 10.

Two unusual cases of intra-atrial gap.

Two cases are described in which, during investigation of rhythm disturbances, it was shown that, by delivering atrial stimuli of increasing prematurity, a point was reached where the artificial stimulus failed to induce an atrial response. However, with even more premature stimulations, atrial responses were again observed. These observations are best explained by a gap phenomenon in which very early stimuli delivered during the effective refractory period of the atria were delayed long enough in the exit area around the pacing electrode to allow atrial recovery.

The efficacy of intravenous mexiletine on ventricular ectopic activity.

Twelve patients with severe ventricular dysrhythmias were treated by one single dose of 250 mg of mexiletine injected intravenously over a 15 min. period. All patients showed some antiarrhythmic response.