Search PubMed⌕ Search

Biomedical subjects

R Frank

Publications and source records attributed to R Frank.

At least 685 records · Page 38Linked to original sources
PubMedDate not supplied

[Sudden death of a patient with a pacemaker caused by heart rupture in a "cloisonné" pericardium].

Myocardial infarction is sometimes accompanied by bradycardia requiring either temporary or permanent cardiac pacing. In addition an MI reduces the amplitude of endocardial action potentials which produces the conditions for defective detection of spontaneous ventricular complexes by the pacemaker. In this particular condition, the competing cardiac rhythm which arises frequently causes malignant arrhythmias which are potentially fatal. This danger is increased even further by endocardial stimulation of the right ventricle with myocardial infarction of the right ventricle. We have reported in this paper the instructive case of a patient with coronary heart disease, hospitalized for third degree AV block with syncope which developed following a massive postero-diaphragmatic MI, but with few symptoms. After secondary extension of the necrotic area, the artificial pacemaker implanted manifested defective firing which resulted in development of ventricular fibrillation. The latter was controlled by cardioversion, but the patient died from disordered conduction after 30 seconds of complete asystole. For one minute, the pacemaker did not stimulate the ventricle because of "electrical stunt to the myocardium", caused by the shock from the defibrillator. Anatomical examination (at autopsy) confirmed the cardiac rupture.

Aged↗
PubMedDate not supplied

Disappearance of organochlorine residues from abdominal and egg fats of chickens, Ontario, Canada, 1969-1982.

Abdominal fats were collected from 8-week old broilers slaughtered at provincially inspected abattoirs across Ontario between 1969 and 1982. Domestically produced hen eggs were collected from either egg grading stations or producers over the same period. Composite samples were analyzed for organochlorine insecticides and industrial chemicals. Between 1979 and 1982, organophosphorus insecticides were routinely included in these analyses. Sigma DDT and PCB residues declined rapidly between 1969 and 1982 in extractable lipids of both abdominal and egg fats, while dieldrin declined less markedly over the same period. Declines in residues followed first order logarithmic regression equations. Chlordane and heptachlor epoxide were rarely observed above the detection limit of 1 microgram/kg in egg fat; however, the incidence of these residues in abdominal fat increased after 1973 following the removal of aldrin, dieldrin, and heptachlor in 1969 and the subsequent increased use of chlordane for soil insect control until 1977. Lindane residues were rarely observed above the detection limit. In 1979, when the detection limit was reduced, both alpha-BHC and lindane were identified, but at levels below 1 microgram/kg. Endosulfan, methoxychlor, and fenthion were identified on one or 2 occasions over the 13-year period.

Adipose Tissue↗
PubMedDate not supplied

[Holter monitoring in patients with focal cerebral ischaemic attacks (author's transl)].

One hundred patients with focal cerebral ischaemic attacks of suspected embolic origin were investigated by Holter monitoring to determine whether paroxysmal arrhythmia may have been responsible for the episodes. There were 57 men and 43 women aged from 16 to 79 years (mean 50 years). Ninety-seven had residual focal neurological deficits and 3 had transient ischaemic attacks. The neurological lesions were verified by cerebral angiography in 68. Twenty-one had arterial hypertension and 9 had old myocardial infarction or angina. Nine had a history of palpitations. None had cardiac valve disease. All patients were in sinus rhythm, 4 had ventricular extrasystoles on routine ECG, and 4 had supraventricular extrasystoles. None of the patients were receiving anti-arrythmic drugs at the time of investigation. Holter monitoring was performed for 18 hours in 91 cases and for 24-54 hours in the remaining ones. The interval between the cerebral ischaemic attack and the monitoring was less than one month (mean 20 days) for 50 patients and longer for the others. Cardiac arrythmias were found in 36 patients. Sixteen had more than 10 supraventricular extrasystoles per hour, 13 had runs of 3 to 8 beats of supraventricular tachycardia, 1 had an episode of atrial fibrillation. Eighteen subjects had more than 5 ventricular extrasystoles per hour, 1 had accelerated ventricular rhythm, 2 had runs of 4 to 7 beats of ventricular tachycardia. Two patients had second degree A.V. block. None had palpitations during monitoring. Arrythmias were increasingly frequent with age. Our findings are similar to those obtained with monitoring in ambulatory asympatomatic subjects of the same age without apparent heart diseases reported by other authors. On the other hand, the frequency of arrythmia was unrelated to the time elapsed between the ischaemic attack and Holter monitoring. In conclusion, Holter monitoring performed several weeks after suspected cerebral embolism failed to reveal arrythmias likely to be responsible for a focal cerebral ischaemic attack.

Adolescent↗
PubMedDate not supplied

[Ventricular response in atrial fibrillation : normal conduction, consequences of conduction disorders and preexcitation syndromes. Therapeutic implications].

Atrial fibrillation is the most common arrhythmia in man. It is characterized by: 1) a rapid and irregular atrial electrical activity, 2) an irregular ventricular response which follows complex laws in the absence of advanced disorder of atrio-ventricular conduction. The study of these laws of complex transformation which govern the ventricular response can be approached by histograms of the RR interval: the shortest interval between two QRS complexes corresponds approximately to the functional refractory period of the atrio-ventricular conduction pathways--the longest interval corresponds to the maximal intranodal hidden conduction in the central part of the node. Depending on the values obtained and the morphological type of the distribution, we can diagnose all degrees of atrio-ventricular conduction disorders. This has great practical significance in patients receiving or about to receive cardiotonics or antiarrhythmics. In the same way, in cases of pre-excitation syndrome, this method can be used to evaluate the refractory period of the accessory pathway and to guide treatment.

Atrial Fibrillation↗
PubMedDate not supplied

[Electrocardiographic effects and antiarrhythmic action of 1200 mg of oral amiodarone per day].

The authors administered 1 200 mg of amiodarone orally to 30 patients with paroxysmal supraventricular and ventricular arrhythmias for a period of 6 days. They evaluated the electrocardiographic modifications induced on the surface ECG as well as the anti-arrhythmic action which was assessed by continuous Holter ECG monitoring and endocavitary electrophysiological investigations. They found that the sinus rhythm was slowed by 22%, that the PR interval was prolonged by 22%, that the QTc interval was increased by 13.5% and that there were alterations in ventricular repolarisation in 48% of cases. These ECG modifications were maximal between the 5th and 7th days. The amiodarone controlled the arrhythmia in 57% of cases. Independent of the nature of the arrhythmia, the anti-arrhythmic effect appeared after a mean of 3.9 +/- 1.8 days. There was no significant relationship between the electrocardiographic modifications and the anti-arrhythmic effect. In three cases (10%), major side effects were observed, related to depression of sinus automatism. They only appeared after the 6th day. Thus, a loading dose of 1 200 mg/day of amiodarone p.o. can be administered without fear of major side effects for 4 to 5 days. Such treatment will control about 60% of cases of severe paroxysmal arrhythmias after 4 days.

Administration, Oral↗
PubMedDate not supplied

[Fulguration of extrasystolic ventricular focus].

A case is presented of symptomatic premature ventricular contractions refractory to drug therapy with right bundle branch block QRS morphology and left axis deviation in a 68-year-old female without structural heart disease. Endocardial mapping localized the extrasystolic focus at meso-inferoapical region of the left ventricular septum suggesting an origin from the Purkinje network of the left posterior fascicle. Catheter ablation with direct-current energy abolished extrasystolic complexes, without complications. The patient remained asymptomatic over a follow-up of 3 months.

Aged↗
PubMedDate not supplied

[Radiofrequency ablation in ventricular tachycardia: initial experience and evaluation of its limitations].

The purpose of this paper is to report our initial experience with radiofrequency catheter ablation in 21 patients with ventricular tachycardia of different etiologies and to evaluate the causes which play a role in its limitation. The results show a low rate of effectiveness: total clinical success of 43%. Nevertheless there was a high success rate in a specific subsets of patients. The results depends on several factors: the electrophysiologic mechanisms and substrates of the tachycardia, the criteria to localize the critical area perpetuating the arrhythmia and the biophysical aspects of radiofrequency energy. Its usefulness is manifested in ventricular tachycardia with structurally normal heart and it has a limited success in cases with organic heart disease. Improvement of technical aspects and better understanding of the mechanisms of the tachycardia and characteristics of the target site will enhance the results of radiofrequency catheter ablation in ventricular tachycardia.

Adult↗
PubMedDate not supplied

[Transcatheter ablation of atrioventricular accessory pathways. Immediate results and long-term follow-up].

We present the immediate results and follow-up, from our initial serie of patients, where radiofrequency was attempted to ablate atrio-ventricular accessory pathways. Initiation policy included direct current-shocks following every unsuccessful radiofrequency session. Initial ablation success rate with radiofrequency solely was 75% (17/22), same as when direct current-shocks were associated 80% (8/10); but accessory pathway conduction recurrence was present only in this latter (6/10). During follow-up period of 18 to 25 months, from the recurrence group, one patient had spontaneous delta-wave disappearance, and four more required two to three ablation sessions. Permanent elimination with both methods was attained in 91% (20/22 pathways), and all patients remain asymptomatic, and drug free. There were one acute major complication, but no deaths. Because of its superior initial success rate, minor technical requirements, and their economical implications, radiofrequency catheter ablation of accessory pathways is the first choice of treatment. At our institution, direct current-shock remain an alternative method whenever a serious tachycardia prevents radiofrequency treatment.

Adolescent↗