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Biomedical subjects

P Rizzon

Publications and source records attributed to P Rizzon.

At least 253 records · Page 14Linked to original sources
PubMed1978

Chronic juvenile AV nodal dysfunction associated with mitral valve prolapse.

The prevalence of atrioventricular (AV) conduction disturbances amongst patients with mitral valve prolapse is higher than may be expected by chance, thus implying the existence of a true association. The main clinical and electrophysiologic findings in 4 patients with mitral valve prolapse showing chronic AV conduction disturbances are presented. Supra-His localization, mild and variable degree of impairment, regression upon Atropine administration, apparent absence of progression, are common features of these disturbances. The most likely mechanisms considered are an AV node developmental abnormality or an AV nodal artery running in contact with the border of the mitral annulus and thus impaired by the abnormal dynamics of the mitral valve.

Adolescent↗
PubMed1977

Effects of prindolol on impulse formation and conduction in man.

Electrophysiologic changes produced by intravenous administration of 0.6 mg Prindolol were studied in 16 subjects with normal impulse formation and conduction. The most important changes were: sinus bradycardia, prolongation of atrial refractory periods, depression of intranodal conduction and prolongation of A-V node refractory periods. Sinus node recovery time was unchanged, and sinoatrial conduction time was only slightly increased. Intraventricular conduction time and the refractory period of the His-Purkinje system and of the bundle branches were unchanged.

Atrioventricular Node↗
PubMed1977

Intra-His bundle block in acute myocardial infarction. Report of two cases.

Two patients with acute intra-His bundle block, both secondary to myocardial infarction, are described. The diagnosis of the block was proved by means of His bundle recordings during the phase of complete atrio-ventricular (A-V) block. Two His bundle potentials, one (H) following each A wave and the other (H') preceding each QRS complex, were detected. In both cases, as well as in the few cases reported in the literature, the site of the infarction was in the inferior wall, an occurrence which shows the functional importance of the posterior blood supply to the His bundle. In both cases the block developed into a chronic form, requiring the implantation of a transvenous pacemaker in one case. This evolution suggests that the post-infarction intra-His bundle block may be due to irreversible anatomic damage.

Aged↗
PubMed1977

Electrophysiologic properties of intravenous oxprenolol in man.

Electrophysiologic modifications produced by intravenous administration of 0.1 mg/Kg Oxprenolol were studied in 16 subjects with estimated normal impulse formation and conduction. Significant effects were sinus bradycardia, mild increase of sino-atrial conduction time, depression of intranodal conduction and prolongation of A-V node refractory periods. Sinus node recovery time and atrial refractory periods were unchanged. Infranodal conduction and the refractory periods of the His-Purkinje system, as well as of the bundle branches, were unchanged. These effects are compared with those observed after intravenous Propranolol and Prindolol.

Adult↗
PubMed1977

Electrophysiologic evaluation of intravenous bunaphtine in man.

The acute electrophysiologic effects of intravenous Bunaphtine 1,5 mg/kg body weight, a new antiarrhythmic drug, were studied in 19 subjects with estimated normal impulse formation and conduction. Significant effects were sinus bradycardia, prolongation of atrial refractory periods, depression of intranodal and infranodal conduction and prolongation of His-Purkinje system refractory periods. These properties are compared with those of amiodarone and quinidine and form the basis for a correct use of Bunaphtine in the management of arrhythmias.

Adult↗
PubMed1976

[Prinzmental's angina and disturbances of the stimulus conduction (author's transl)].

Our series (30 cases) of variant angina as well as the reports from literature, were reviewed, to investigate the consequences of an acute regional ischemia on seno-atrial, atrio-ventricular and intraventricular conduction. Sinoatrial conduction was never affected independently from the anterior or posterior localization of the ischemia. A junctional impairment of atrio-ventricular conduction was rather frequent in cases of variant angina affecting the inferior wall, ranging in different series from 8% to 25%. Only one case of bundle branch block was observed. Hemiblocks were found to be extremely rare, while a deviation of the main axis of the QRS on the frontal plane, especially to the left in cases with anterior localization of the ischemia, was observed quite frequently. This axis deviation, in the absence of changes of the initial vector of the QRS compatible with the diagnosis of hemiblocks, were considered to be depending on a parietal block.

Angina Pectoris↗
PubMed1976

[Mitral valve prolapse and the ventricular pre-excitation syndrome (author's transl)].

One of the most important clinical aspects of the mitral valve prolapse syndrome is the high incidence of arrhythmias. Some recent reports on the association of mitral valve prolapse with ventricular pre-excitation may be relevant to the understanding of such arrhythmias. In order to evaluate the clinical relevance of this association, all patients with proven idiopathic mitral valve prolapse who came under our observation during the last twelve months, were submitted to careful electrocardiographic examination with the aim of detecting even subtle degrees of pre-excitation. His bundle recording and programmed atrial stimulation were performed if there was any suspicion of a delta wave. The association with ventricular pre-excitation was proved in 6 out of 41 examined cases. The main clinical, phonocardiographic, echocardiographic, angiographic and electrophysiologic data, as well as the familial study of these cases, are presented. The need for electrophysiologic study in some cases with doubtful electrocardiographic pattern is pointed out. While previous reports only described cases with left-sided accessory pathways, examples of right-sided pathways are presented in our series. The high incidence of mitral valve prolapse, and especially of pre-excitation syndrome and arrhythmias in the familial study, suggests that the association is not an occasional one. The detection of ventricular pre-excitation in cases of mitral valve prolapse complicated by recurrent tachy-arrhythmias may be of practical importance for an appropriate therapeutic approach.

Adult↗
PubMed1976

[Coronary spasm and acute coronary insufficiency (author's transly)].

A series of cases illustrating a spectrum of acute coronary episodes associated with transient subepicardial injury, namely the variant form of angina, angina intermedia with electrocardiographic changes similar to those of the variant angina, acute myocardial infarction complicated by variant angina with electrocardiographic changes localized to the infarcted area, acute myocardial infarction preceded and followed by variant angina, is presented. The role of a coronary spasm as a common mechanism of the above mentioned episodes is postulated. Coronarographic demonstration of this mechanism is produced.

Adult↗
PubMed1976

[Ischemic lesions of the left branch of the bundle of His. Their relation of left hemiblock].

The term "hemiblock of the left branch of the bundle of His" seems to a histologist to be too precise to be accepted without reservation. Ten cases with septal infarction, with or without left intraventricular conduction problems, were studied by serial sectioning of the heart; these are used as a basis for a discussion of the concepts of electrocardiography, and its implications in the prognosis of patients with myocardial necrosis.

Bundle of His↗