Arrhythmias and Conduction Disease — Written Clinical Reasoning

Model answer — Part A: new AF with rapid response in sepsis

Frame the problem first. New AF in sepsis is common and is usually a marker of physiological stress rather than primary cardiac disease. The first question is stability: hypotension, worsening perfusion, ischaemia or pulmonary oedema attributable to the tachycardia would mandate synchronised cardioversion even in a septic patient ^[1]. His blood pressure of 100/60 on a weaning noradrenaline dose is borderline rather than frankly unstable — but the answer must state that any deterioration buys a shock, not a drug escalation ^[1].

Treat the driver. Sepsis, hypoxia, hypovolaemia, pain, electrolyte disturbance and catecholamine infusions all perpetuate the arrhythmia. The highest-yield management is aggressive treatment of the sepsis, correction of potassium and magnesium, and review of whether the noradrenaline dose can fall — rate often settles as the physiology settles ^[1].

Rate versus rhythm reasoning. In the critically ill, rate control is the pragmatic default: cardioversion in septic new AF has a high early recurrence rate while the trigger persists, and antiarrhythmic loading interacts with a shocked circulation. A sensible stated position is rate control now — a beta-blocker if the pressure allows, or digoxin where borderline perfusion limits beta-blockade — with amiodarone reserved for failure, and elective cardioversion reconsidered once the sepsis resolves if AF persists ^{[1] [5]}. A strong answer adds the EAST-AFNET 4 framing for later: once recovered, this is recently diagnosed AF with cardiovascular risk factors, where early rhythm-control strategy discussion belongs in outpatient follow-up rather than on the septic ward ^[2].

Anticoagulation now and at discharge. Do not start therapeutic anticoagulation reflexively during the acute unstable phase — but do not forget it either. The structured answer: calculate CHA₂DS₂-VASc now, reassess bleeding risk while septic and thrombocytopenic-prone, withhold during active instability and any planned procedures, and make a documented decision before discharge — a man of 68 with AF and vascular comorbidity will very likely meet the anticoagulation threshold, where a DOAC is preferred over warfarin for non-valvular AF ^{[3] [4]}.