Final answer:
Normal Sinus Rhythm (NSR) is the regular heartbeat initiated by the sinoatrial node, with a normal adult resting heart rate of 60-100 bpm. Bradycardia is below 60 bpm and tachycardia is above 100 bpm. Treatment of heart rhythm disorders depends on the underlying cause and may include addressing electrolyte imbalances or ischemia.
Step-by-step explanation:
Understanding Normal Sinus Rhythm (NSR)
Normal Sinus Rhythm (NSR) refers to the standard, regular heartbeat that occurs when the heart is functioning properly. The sinus rhythm is the normal contractile pattern of the heart, which starts in the sinoatrial node, responsible for setting the pace of the heart. In adults, a normal resting heart rate (HR) ranges from 60-100 beats per minute (bpm). When the heart rate drops below 60 bpm, the condition is known as bradycardia, and when it exceeds 100 bpm, it is referred to as tachycardia. Trained athletes may experience lower resting heart rates without adverse symptoms, which is typically not a cause for concern.
Bradycardia may not be clinically significant if the patient does not exhibit symptoms. However, if symptoms such as weakness, dizziness, or chest discomfort are present, it may indicate insufficient oxygenated blood flow to body tissues. Treatment for heart rate disorders focuses on identifying and addressing the underlying cause, which can range from electrolyte imbalances to endocrine system pathologies or heart muscle ischemia.
Effects of both parasympathetic and sympathetic stimulation can alter the normal sinus rhythm. Parasympathetic stimulation typically results in a slower heart rate, while sympathetic stimulation leads to an increased heart rate.