What is the first-line treatment for bradycardia with life-threatening features?

The first-line treatment for bradycardia with life-threatening features is atropine. Atropine is an anticholinergic agent that works by inhibiting the vagus nerve's effects on the heart, leading to an increase in heart rate. In cases of symptomatic bradycardia, particularly when the bradycardia is causing significant hemodynamic instability, atropine is administered as it acts quickly to alleviate the symptoms associated with insufficient cardiac output.

Bradycardia can often present with dangerous symptoms such as hypotension or altered mental status, making prompt treatment essential. Atropine is indicated in these scenarios because it effectively counteracts the excessive vagal tone that can lead to dangerously low heart rates. Its rapid action allows medical personnel to stabilize the patient while further assessment and supportive measures are implemented.

In contrast to atropine, other medications such as isoprenaline are not typically used as first-line treatments due to their more indirect effects on heart rate and potential side effects. Aminophylline and glucagon also do not serve as primary interventions for severe bradycardia and are not indicated in acute management of this condition. Thus, atropine stands out as the recommended initial approach when addressing bradycardia with life-threatening features.