Bradycardia - ischemia (less than 60 beats per 1 min) heart rate (absolute bradycardia) or lag increase in pulse from increased body temperature (relative bradycardia). Absolute bradycardia may occur in healthy people. As a pathological symptom occurs when jaundice, increased intracranial pressure (with meningitis, brain tumor, a brain haemorrhage, shock, miksedeme, starvation, lead poisoning, under the influence of quinine, digitalis. Relative bradycardia typical of influenza, typhoid fever. Most often bradycardia occurs when the slowdown in the production of pulses in the sinus node - sinus bradycardia. It usually develops as the result of increase of a tone of the vagus nerve. Rarely aetiology related to the violation of conduction of impulses from the Atria to the ventricles. Unsharp aetiology not affect the blood circulation. Very sharp bradycardia may cause dizziness, loss of consciousness due to anemia of the brain. In such cases it is recommended injections under the skin of 1 ml of 10% solution of caffeine, 1 ml of 0.1% solution of sulphate of atropine.

Bradycardia (from the Greek. bradys - slow and kardia - heart) - reduction in heart rate below 60 beats per 1 min. Bradycardia occurs as normal, constitutionally due to the phenomenon of completely healthy people, well-trained athletes and also as one of the symptoms in many diseases.
Bradycardia may be caused by: a) the slowing of the pulse shaping in the sinus node in the result of oppression his excitability (the so-called sinus bradycardia) and b) the receipt termination impulses from the sinus node to the ventricles in violation atrioventricular conduction, causing the ventricles moving to a more rare than sinoatrial, atrioventricular or ventricular (the so-called idioventricular) the rhythm (Arrhythmia). Depression anxiety sinus node can be associated with the development of pathological processes in the heart (for example, sclerotic changes of myocardium) or by exposure to certain products of metabolism (e.g., bradycardia at jaundice) and medications (for example, quinine).
However, the most frequent reason is the strengthening of the parasympathetic influences on the heart by instituting centers stray nerves (for example, tumors, swelling and edema of the brain, in hemorrhages in the brain and the effects of some medicinal substances) or irritation of these nerves over (for example, tumors of the mediastinum). Bradycardia occurs when the reflex excitation of nuclei vagi (as a result of irritation baroretseptorov carotid sinus) and aortic arch (raising blood pressure), with pressure on the eyeballs (reflex of Dagnini - Achnera), irritation of receptors of the upper respiratory tract (e.g. ammonia fumes)receptors mesentery, peritoneal and internal organs (e.g., bradycardia with biliary colic)and Dura mater. Aetiology, as a rule, is observed in uremic and diabetic coma, typhoid fever, with agony. When hypothyroidism and starvation appearance bradycardia attributed to the decrease in sympathetic affects the heart.
Moderate aetiology itself does not cause any hemodynamic disorders. However, severe and prolonged B. may cause circulatory disorders in the periphery and especially in intracranial arteries. Very sharp B. accompanied by significant pale skin and mucous membranes, loss of consciousness and seizures as a result of anemizatsii brain. Cm. the Pulse.