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Biomedical subjects

H E Kulbertus

Publications and source records attributed to H E Kulbertus.

At least 109 records · Page 6Linked to original sources
PubMed1978

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. 10.7% were found to have elevated blood pressure (greater than 160/95 mm Hg). Among these subjects, 43% of the male and 24% of the female had never been told they were hypertensive. 5.6% of the men and 7% of the women had a diastolic reading of 105 mm Hg or more. Undetected hypertension decreased with age and was less frequent in women than in men. Young male hypertensives were frequently aware of their disease. When known, hypertension remained untreated in 14.5% of cases and badly controlled in 26%. One yr after screening, 400 patients who had been found to have undetected hypertension were contacted; 358 (89.5%) had seen their family doctor and 42% of them were under continuous medical treatment. These results further underline the challenge of undetected, untreated and uncontrolled hypertension.

Adult↗
PubMed1978

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. Their approach restricts position, direction and polarity of the current dipole vectors in the model. In the Selvester model, and later in the Ritsema van Eck model, in addition to these restrictions time-constraints are imposed on the dipole activity. In a validation study of the Ritsema van Eck model activation of a beating dog heart is compared in detail with simulated activation in a computer replica of the same heart. Myocardial spread of activation is found to be stimulated correctly. Simulated spread of activation along the Purkinje fiber network however, differs considerably from reality. In apical regions excitation spreads in reality much faster than in the model, in basal regions much slower. The model can be improved by slowing endocardial excitation from apex to base with the time-course of activation. Further improvement is obtained by the use of a more detailed pattern of endocardial excitation, based on studies of endocardial excitation in opened ventricles. The model can predict the time-course of activation with an accuracy of 5% of total ventricular activation time.

Action Potentials↗
PubMed1978

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. A further 30 yr were needed to obtain a sound correlation between these functional disorders and the presence of anatomical lesions. The more recent introduction of the concept of left hemiblocks further improved our understanding of intraventricular conduction defects. The latter concept is based on the hypothesis of the anatomical and functional bifascicularity of the left bundle branch, a hypothesis which cannot be accepted without some reservations. Later developments indicated that left hemiblocks associated with right bundle branch block represent manifestations of bilateral conduction disturbances (incomplete bilateral bundle branch block). Such an association may constitute a forerunner of complete atrioventricular block, or an indicator of the possibility of sudden death. Whether these complications occur frequently or unfrequently in the setting of incomplete bilateral bundle branch block remains an unsettled question.

Adult↗
PubMed1977

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.

Arrhythmias, Cardiac↗
PubMed1977

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. In 9 cases, the ventricular premature beats were totally or almost totally abolished up to 20 to 100 min. after the end of the infection. In most patients (5/7), there existed a correlation between the plasma concentration of the drug and the antiarrhymic action. However, the drug levels were not different in the good responders as compared to the poor responders or in those who manifested a prolonged antiarrhythmic activity as compared to the others. Side-effect appeared in three cases and consisted of vomiting, tremor, and episodes of sinus arrest.

Aged↗
PubMed1976

Vectorcardiographic study of aberrant conduction anterior displacement of QRS: another form of intraventricular block.

Aberrant ventricular conduction was induced in 44 subjects by introduction of atrial premature beats through a transvenous catheter-electrode. Multiple patterns of aberrant ventricular conduction were obtained in 32 patients and, in the whole group, 116 different configurations were recorded. Of these, 104 showed a classical pattern of mono- or biventricular conduction disturbance. The pattern frequencies were as follows: right bundle-branch block, 28; left anterior hemiblock combined with right bundle-branch block, 21; left anterior hemiblock, 17; left posterior hemiblock combined with right bundle-branch block, 12; left posterior hemiblock, 10; complete left bundle-branch block, 10; and incomplete left bundle-branch block, 6. The remaining 12 configurations could not be classified into the usual categories of intraventricular blocks. In 7 of them, the alterations only consisted of trivial modifications of the QRS contour. In the other 5 instances, aberrant conduction manifested itself by a conspicuous anterior displacement of the QRS loop, with increased duration of anterior forces. The latter observation is worthy of notice, as it indicates that, in the differential diagnosis of the vectorcardiographic pattern characterized by prominent anterior forces, conduction disturbances should be considered a possible aetiological factor in addition to right ventricular hypertrophy, and true posterior wall myocardial infarction.

Adolescent↗
PubMed1975

Quantitative study of left bundle branch fibrosis in left anterior hemiblock: A stereologic approach.

Serial sectioning of the interventricular septum was carried out in 16 hearts, 8 from elderly subjects with no conduction disturbance and 8 from patients with chronic left anterior hemiblock. The histologic slides were studied stereologically, and the relative density of fibrosis was quantitatively assessed by the point counting technique at various levels of the main subdivisions of the left bundle branch system. Statistical analysis revealed the following: (1) Although some fibrosis was found in the control hearts, the density of fibrosis was consistently and significantly greater throughout the conduction system in patients with left anterior hemiblock. (2) In the group with hemiblock, the relative density of fibrosis tended to increase significantly from the posterior ramification to the midseptal fibers and, finally, to the anterior fascicle. (3) Among the eight patients with hemiblock, fibrosis appeared to be evenly distributed throughout the conduction system in four. It was predominantly located in the anterior and midseptal fibers in one patient and showed an increasing severity from the posterior to the midseptal and anterior fibers in the remaining three patients. From this quantitative study, it is concluded that left anterior hemiblock is a reliable sign of left bundle branch disease but that the underlying lesions are more widely distributed than would be from the expected electrocardiographic terminology since they were found predominantly in the anterior ramifications in only half of the studied cases.

Adult↗
PubMed1975

Sinus node recovery time in the elderly.

Measurement of the sinus node recovery time has been proposed as a diagnostic tool for recognition of the sick sinus syndrome. The latter is most frequently encountered in elderly patients with hypertension, coronary heart disease, and atherosclerosis. In order to provide normal values for the sinus node recovery time in this particular population group, atrial pacing studies were carried out in 30 subjects over 50 years of age, all with peripheral vascular disease and some with angina pectoris (10), residua of infarction (6), or hypertension (7). On stimulation, 7 patients maintained a I:I atrioventricular conduction up to the rate of 180/min. Second degree atrioventricular block developed in all other cases. On six occasions, Wenckebach's periods appeared at the relatively slow pacing rate of 120/min. The maximum postoverdrive pause ranged from 680 to 1600 ms with an average of 1100 ms plus or minus 190 (10). For each pacing speed, a correlation was found between the duration of the pause and the control intrinsic cardiac rate, longer pauses being associated with longer resting PP intervals. Beyond 120/min, the duration of the pause was seen to shorten progressively as the driving rate was increased. Finally, the behavior of the sinus node pacemaker following interruption of pacing showed individual variations. After pacing at relatively slow rates, a prompt return to near control values was consistently observed, whereas, after fast rates of driving, a phase of secondary depression developed in about one-half of the studied cases.

Action Potentials↗
PubMed1975

[Complete atrioventricular block in bacterial endocarditis].

A case of bacterial endocarditis complicated by complete auriculoventricular block is reported. The pathological findings and data from previously reported cases point to the fact that this complication is generally indication of very extensive cardiac and valvular damage. Surgery, although dangerous, should be attempted in the circumstances.

Aged↗