A wet, hyperkalaemic heart failure patient with a wide QRS
A 68-year-old retired teacher with heart failure and reduced ejection fraction (ejection fraction 28%) is admitted with three weeks of worsening breathlessness. He is NYHA class III, has atrial fibrillation and takes apixaban. Current medication: sacubitril/valsartan 97/103 mg twice daily, bisoprolol 5 mg daily, furosemide 80 mg daily and spironolactone 25 mg daily. Blood pressure 104/66 mmHg, pulse 88 irregular, JVP raised, bilateral crackles to mid-zones, 3+ pedal oedema. Bloods: sodium 134, potassium 5.3 mmol/L, creatinine 168 micromol/L (eGFR 32), haemoglobin 11.8 g/dL, ferritin 45 ng/mL, transferrin saturation 12%. ECG: QRS 152 ms with left bundle branch block. He remains congested despite oral diuretic. Echocardiography confirms severely impaired systolic function.
1. He is congested and hyperkalaemic on near-maximal neurohormonal therapy. Set out your plan for the next 72 hours: what you would start, stop or defer, and the reasoning for each decision at the bedside.
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He is wet, hyperkalaemic and already on a near-maximal regimen, so the next 72 hours are about decongestion first and neurohormonal sequencing second - not about adding every drug at once.
Hours 0–24
- Give intravenous furosemide (40 mg bolus then infusion 5–10 mg/h, or 40 mg boluses 6-hourly) and target a negative balance of 1–1.5 L/day, with daily weight, strict fluid chart, urine output and orthostatic blood pressure. Do not stop bisoprolol; beta-blocker withdrawal in HFrEF with AF risks rebound tachycardia.
- Stop any potassium supplement, potassium-containing salt substitute, NSAID or trimethoprim. Recheck urea, electrolytes and magnesium 12-hourly.
- Potassium 5.3 with eGFR 32 is not a reason to abandon the MRA permanently, but it is a reason to defer dose escalation. If potassium rises above 6.0 or the ECG shows peaked T waves, hold spironolactone and treat.
- Once he is decongested and not hypotensive, start dapagliflozin 10 mg daily: it lowers potassium slightly, slows eGFR decline and reduces mortality. It is not a substitute for diuretic in acute congestion, but can be started during admission if he is eating and euvolemic.
- To preserve the MRA, use a potassium binder (patiromer or sodium zirconium cyclosilicate) with dietary review, then recheck potassium at 48–72 hours and rechallenge spironolactone 12.5 mg if potassium is ≤5.0.
- Reassess sacubitril/valsartan if systolic pressure falls below 90 mmHg; reduce rather than stop.
The judgement is to treat congestion and hyperkalaemia simultaneously rather than choosing between diuretic and MRA.
2. After decongestion he is stable and euvolemic, potassium 4.6 mmol/L, eGFR 34. Discuss referral for a cardiac device, explaining how his atrial fibrillation and the timing of referral affect your decision.
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He has a class I indication for cardiac resynchronisation on the basis of ejection fraction ≤35%, NYHA III–IV despite optimal therapy, and QRS ≥150 ms with left bundle branch block. His atrial fibrillation changes both the strength of evidence and the practical delivery.
- CRT: In AF, biventricular pacing only works if capture is near-complete (above 90–95%). If his ventricular rate is fast or he has frequent conducted beats, plan for AV-node ablation at the time of implant. Without guaranteed capture, the mortality benefit is attenuated. Refer now rather than waiting, because the combination of LBBB, wide QRS and AF with uncontrolled rate predicts progression; do not delay three months solely to satisfy a trial criterion if he remains symptomatic.
- ICD: Primary prevention is reasonable after at least three months of optimal medical therapy with documented ejection fraction ≤35%, expected survival more than one year and good functional status. If CRT is implanted, a CRT-D device covers both. Discuss the competing risk of non-arrhythmic death and his own priorities; CKD stage 3b raises periprocedural risk but is not an absolute contraindication.
- Before device: confirm euvolemia, repeat echocardiography after decongestion (ejection fraction can improve), correct iron deficiency with intravenous ferric carboxymaltose (ferritin below 100 with transferrin saturation below 20%), and document rate control.
- Do not forget: continue anticoagulation and screen for dental or line infection before implant.
The decision hinges on capturing the ventricle in AF, not on the QRS width alone.