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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Based upon electrocardiographic studies of conduction disturbances, the human intraventricular conduction system has been considered trifascicular: a right bundle and a bidivisional left bundle. Right bundle branch block, left anterior hemiblock, and left posterior hemiblock have been described. Microscopic and endocardial mapping studies, however, do not demonstrate a corresponding anatomical basis of this useful functional concept. Atrial premature beats in our two cases resulted in ventricular aberrancy which strongly suggests an additional form of a functional conduction delay. Such delay is manifest as a narrow QRS with anterior displacement in the horizontal plane but no axis shift in the frontal plane. This aberrancy is important to recognize because it can mimic the ECG findings of true posterior myocardial infraction. We do not postulate, however, a specific fascicle of the left bundle as the anatomic substrate for this recently recognized effect.
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PMID:Pure anterior conduction delay: a variant "fascicular" defect. 71 83

Seventy three infants who underwent neonatal anatomical correction for transposition of the great arteries with or without a ventricular septal defect were reviewed for evidence of conduction and rhythm abnormalities on preoperative and postoperative 12 lead electrocardiograms and during 24 hour Holter monitoring. There was a partial right bundle branch block pattern in 47% (29/62) of all patients and in 60% (24/40) of those with simple transposition. Complete right bundle branch block was noted in 21% including 5% with simple transposition. Holter monitoring showed sinus rhythm in all patients except three: one had episodes of supraventricular tachycardia, another an intermittent second degree heart block, and a third a complete heart block. Atrial extrasystoles were noted in 47% (29/62) of patients but were frequent in only three patients. Occasional unifocal ventricular extrasystoles were encountered in 37% (23/62) of patients and were frequent in a further 3% (2/62). Only one patient (2%) developed multifocal ventricular extrasystoles. The frequency of important cardiac arrhythmias after neonatal anatomical correction of transposition of the great arteries was 5%, significantly less than that reported after atrial inflow diversion for the same malformation.
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PMID:Cardiac conduction abnormalities and rhythm changes after neonatal anatomical correction of transposition of the great arteries. 155 42

Normal electrocardiographic criteria in the elderly are not well defined. The prevalence of electrocardiographic abnormalities is three times higher in subjects over 85 years than in subjects 65-69 years old. With aging the heart rate does not vary during rest and sinus rhythm is prevalent, although sinus pauses, overall at night, are frequently seen. First degree atrio-ventricular block is present in 8.1%-19% of the elderly. 11% of subjects over 70 years suffer from left anterior hemiblock. 4.3% of subjects over 65 years and 7% of those over 85 present a right bundle branch block. 1.7% of subjects older than 65 years and 9% of those older than 85 are affected by a left bundle branch block. Atrial ectopic contractions are present in 8.8% of subjects over 60 years and in all older subjects. Atrial fibrillation is more common as age increases, being found in 2% of under 75s, in 5% of all subjects over this age, in 14% over 85 years and in 27% of patients hospitalized or institutionalized aged over 90 years. The prevalence of ventricular ectopic contractions varies from 76% in studies performed with baseline electrocardiogram to 96% in studies performed with portable monitoring electrocardiogram. Major ST-T wave alterations are present in 6.3%-13% of the elderly. In 340 patients over 80 years, hospitalized for diseases, other than cardiovascular, we found atrial fibrillation in 27.9% of subjects, ectopic beats in 26.2%, first degree atrioventricular block in 8.5%, right bundle branch block in 11.2%, left bundle branch block in 5.9%, left anterior hemiblock in 8.2%, ST-T wave alterations in 23.8% of the population.
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PMID:[Changes in the electrocardiogram in the elderly patient. The limits between normality and pathology]. 770 41