Heart rate and drugs affecting heart rate

Heart rate refers to the rate of heart beat. It helps in quick evaluation of an individual’s health.
Autonomic nervous system (ANS) controls heart rate. ANS is, usually, associated with the regulation of heart, secretory glands, and smooth muscles.
In the ANS, sympathetic nervous system acts through beta1-adrenergic receptors in the sinoatrial (SA) node and increase the heart rate. The increase in heart rate is also referred to as tachycardia. Here, SA node is a specialized part in heart involved in pacemaker activity and control of heart beat. Muscarinic antagonists, such as atropine, also cause an increase in heart rate. Sympathetic nervous system is, usually, involved in regulation of cardiovascular system and body temperature.
On the other hand, in the ANS, parasympathetic nervous system acts through muscarinic receptors and decrease the heart rate. The decrease in heart rate is also referred to as bradycardia. Muscarinic agonists, such as bethanechol and pilocarpine, usually work through muscarinic receptors. Parasympathetic nervous system is, usually, involved in slowing of heart rate, emptying of bladder and bowel, and constriction of pupil.
Zusammenfassung in deutscher Sprache (Summary in German language)
Die Herzfrequenz bezieht sich auf die Herzschlagfrequenz. Das autonome Nervensystem steuert die Herzfrequenz. Das sympathische Nervensystem wirkt über Beta1-adrenerge Rezeptoren und erhöht die Herzfrequenz. Das parasympathische Nervensystem wirkt über Muskarinrezeptoren und senkt die Herzfrequenz.
Source:
Burchum, J., Rosenthal, L., & Yeager, J. J. (2018). Study Guide for Lehne’s Pharmacology for Nursing Care *- eBook. Elsevier Health Sciences.