🚨 Bradyarrhythmias

Bradyarrhythmias are abnormally slow heart rhythms, typically defined as <60 bpm, which can lead to reduced cardiac output and organ hypoperfusion. They range from benign sinus bradycardia to life-threatening complete heart block requiring urgent intervention. UK management follows Resuscitation Council guidelines, focusing on identifying and treating reversible causes.

Patients may present with syncope, pre-syncope, dizziness, fatigue, dyspnoea, or chest pain. Severe bradycardia can cause hypotension, altered mental status, and signs of shock. Always consider drug-induced causes (e.g., beta-blockers, calcium channel blockers) or underlying cardiac conditions.

A: Ensure airway patency, check for stridor. B: Assess breathing rate, effort, and oxygen saturation; administer high-flow oxygen if hypoxic. C: Palpate pulse, measure blood pressure, assess capillary refill time, and obtain a 12-lead ECG immediately. D: Assess conscious level using AVPU/GCS, check pupillary response. E: Expose patient to look for signs of trauma or other pathology, check temperature.

Persistent hypotension (systolic BP <90 mmHg), signs of shock (cool peripheries, prolonged capillary refill, altered mental status), acute heart failure (pulmonary oedema), or myocardial ischaemia (chest pain, ECG changes) indicate haemodynamic instability. These necessitate immediate and aggressive management.

Bedside: 12-lead ECG (essential for rhythm diagnosis), continuous cardiac monitoring, pulse oximetry, blood pressure monitoring, blood glucose. Bloods: FBC, U&Es, LFTs, cardiac enzymes (troponin), thyroid function tests, toxicology screen if drug overdose suspected. Imaging: Chest X-ray if pulmonary oedema or other lung pathology is suspected.

If haemodynamically unstable, administer atropine intravenously. If no response, consider transcutaneous pacing or intravenous inotropes/vasopressors. Address reversible causes such as hypoxia, electrolyte imbalances, or drug toxicity. Prepare for transvenous pacing if temporary measures are ineffective or for long-term management. Maintain oxygen saturation and fluid balance.

Immediate senior medical review (Registrar/Consultant) is required for any haemodynamically unstable bradyarrhythmia. Cardiology consultation is essential for persistent symptomatic bradycardia or high-grade AV block. Consider ICU referral if requiring significant inotropic support or complex pacing.

First-degree AV block and Mobitz type I (Wenckebach) are often benign and asymptomatic, not requiring acute intervention unless symptomatic. Mobitz type II and complete heart block are more serious, often requiring pacing. Remember the 'P' wave relationship to QRS complexes on ECG for block diagnosis. Atropine is contraindicated in transplanted hearts and some high-grade blocks.