Final answer:
Symptoms of instability are often not associated with heart rates below 50 bpm unless there is impaired ventricular function. Bradycardia, a condition where the resting heart rate is below 60 bpm, can indicate insufficient blood flow if symptoms like dizziness or fatigue are present. Treatment targets the underlying causes, which could vary from node irregularities to metabolic disorders or heart disease.
Step-by-step explanation:
Symptoms of instability are not usually caused by heart rates less than 50 bpm unless ventricular function is impaired. A normal resting heart rate (HR) for an adult ranges from 60 to 100 bpm, with bradycardia defined as a condition where the resting rate drops below 60 bpm. While bradycardia is not considered clinically significant without the presence of symptoms like weakness, fatigue, dizziness, fainting, chest discomfort, palpitations, or respiratory distress, it can indicate that the heart is not delivering enough oxygenated blood if these symptoms are present. Relative bradycardia is a term that can be used when a patient's heart rate is within the normal range but symptoms are still experienced. The underlying causes of bradycardia can be nuanced, including problems with the sinoatrial (SA) or atrioventricular (AV) node, ischemic conditions, metabolic disorders, external factors like drug use, or diseases affecting the heart muscle or valves. Determining and addressing the underlying issue is crucial for treatment, which may involve employing a pacemaker, providing supplemental oxygen, or medications.