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Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. [6] It is typically given intravenously or by injection into a muscle. [6]
Heart rate variability visualized with R-R interval changes Electrocardiogram (ECG) recording of a canine heart that illustrates beat-to-beat variability in R–R interval (top) and heart rate (bottom). Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the ...
In the heart, they act to slow the heart rate down below the normal baseline sinus rhythm, by slowing the speed of depolarization. In humans, under resting conditions, vagal activity dominates over sympathetic activity. Hence, inhibition of M 2 receptors (e.g. by atropine) will cause a raise
Atropine acts on the M2 receptors of the heart and antagonizes the activity of acetylcholine. It causes tachycardia by blocking vagal effects on the sinoatrial node . Acetylcholine hyperpolarizes the sinoatrial node; this is overcome by MRAs, and thus they increase the heart rate.
The vagus nerve acts on the sinoatrial node, slowing its conduction and modulating vagal tone, via the neurotransmitter acetylcholine and downstream changes to ionic currents and calcium of heart cells. [4] Because of its effect on heart rate, and cardio health, vagal tone can be measured and understood by examining its correlation to heart ...
In the 1850s, atropine was used as antispasmodic in asthma treatment and as morphine antidote for its mydriatic effect. [4] Bezold and Bloebaum showed that atropine blocked the effects of vagal stimulation on the heart in 1867. Subsequently in 1872, Heidenhain found its ability to prevent salivary secretion. [6]
Atropine is often used as a first line treatment of a third-degree heart block in the presence of a narrow QRS which indicates a nodal block, but, may have little to no effect in an infra-nodal block. [11] Atropine works by reducing vagal stimulation through the AV node but will not be effective in those who have had a previous heart transplant ...
A medical monitoring device displaying a normal human heart rate. Heart rate is the frequency of the heartbeat measured by the number of contractions of the heart per minute (beats per minute, or bpm). The heart rate varies according to the body's physical needs, including the need to absorb oxygen and excrete carbon dioxide.