PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Heart Conduction System”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1999

Neurocardiology: the benefits of irregularity. The basics of methodology, physiology and current clinical applications.

Cardiovascular variability in heart rate and blood pressure can be used to quantify the autonomic modulation of cardiovascular function. Although the first studies were only published 10 to 20 years ago, there is presently a vast amount of knowledge from numerous publications that allows a better insight into the neural control mechanisms of the heart. The development of methods such as heart rate variability and baroreflex sensitivity prompted a multidisciplinary approach since many aspects were involved: mathematics, signal processing, physiology and cardiology. Therefore, it is obvious that an adequate understanding of certain basic principles is necessary before its clinical potential can be fully exploited. This current review outlines the physiological background and the fundamental methodology used in the field of neurocardiology by presenting the newer insights and developments from both fundamental and clinical sides. Recent publications indicate that neurocardiological applications in (risk stratification of) myocardial infarction, congestive heart failure and heart transplant patients can be expected to enter daily clinical practice in the next millennium.

Baroreflex↗
PubMed1985

Role of autonomic nervous system on heart rate in experimental hypertension.

Heart rate and the role of the autonomic nervous system in hypertensive conscious rats by subtotal nephrectomy were studied. Heart rate is significantly higher in the hypertensive rats. Sympathetic blockade with an intravenous injection of propranolol produces a higher decrease in heart rate of hypertensive rats than in control rats. Intravenous injection of atropine produces an increase in heart rate in both groups of animals. It is significantly higher in the control rats than in hypertensive animals. When the autonomic nervous system is blocked with atropine and propranolol, intrinsic heart rate is similar in both groups of animals. Similar results are obtained after blocking ganglionic transmission with hexamethonium. No significative differences are observed in heart rate after intracerebroventricular injection of hemicholinium-3 between both groups of rats. Results show an increased cardiac sympathetic tone, reduced parasympathetic activities, no alterations in the pacemaker activity and implications of central acetylcholine. These alterations in the autonomic nervous system have an important role in the maintenance of elevated heart rate in this experimental model of arterial hypertension.

Animals↗
PubMed1979

[Clinical use of electrical atrial stimulation].

Electric auricle stimulation (EAS) was realized in a total of 77 patients. In 60 of the patients EAS was performed as a hypoxic test (step-wise increase of heart rate, with ECG registration and in many of the cases -- registration of certain indices of general and intracardial hemodynamics) with a view to precise diagnosis of ischemic heart disease and assessment of myocardial contraction function. In 91 per cent of the patients with stenosed coronary pathology on coronarogram, the symptoms of coronary insufficiency were positive (pain attack, ECG changes via ischemic type and/or deterioration of the myocardial functional curve) with the aid of EAS. Various correlations were established between the manifestations of coronary insufficiency and the deterioration of the functional curve of left ventricle. Furthermore, in the majority of the cases, one way results, among the data of veloergometry, coronarography and EAS, were recorded. In some cases EAS provided additional data for coronary insufficiency with negative veloergometric test (7 patients) and negative coronarography (5 patients). EAS could be applied in the diagnostics of ischemic heart disease, and in a hemodynamic aspect, via EAS a myocardial loading is realized with a minimum change of cardiac index and aortic pressure. In 16 patients EAS was applied with a view to the investigation of the functional state of sinal node and heart conduction system. In 13 patients, data about the syndrome of morbid sinal node were found (pathologic time of sinal node restoration) or for a latent lesion of heart conduction system. In the other three patients the suspicion of syndrome of morbid sinal node was not confirmed. The data obtained contributed to the determination of the therapeutic approach of those patients. In 5 patients a high frequency auricle electrostimulation was applied successfully in the interruption of paroxysms of supraventricular tachycardia. EAS was concluded, on the base of the data obtained, to be appropraite for application and precise diagnosis of ischemic heart disease, as well as in the studies on sinal node state and heart conduction system. In some rhythm disturbances, resistant to medicamentosus treatment, the electric auricle stimulation could prove a valuable therapeutic method.

Coronary Disease↗