Can atrial fibrillation cause heart failure?

Yes. AF can lead to heart failure through several mechanisms: the irregular rapid heartbeat reduces the heart's pumping efficiency, prolonged tachycardia can cause tachycardia-induced cardiomyopathy, and loss of coordinated atrial contraction reduces cardiac output by 20-30%. Conversely, heart failure can also cause AF by stretching the atria. The two conditions frequently co-exist and worsen each other.

What's the difference between HFrEF and HFpEF in trials?

HFrEF (heart failure with reduced ejection fraction, EF <40%) has a larger trial landscape with proven drug and device therapies. HFpEF (preserved EF, ≥50%) has fewer approved treatments and is a major research focus. Some trials also include HFmrEF (mid-range, 41-49%). Your echocardiogram results determine which category — and therefore which trials — apply to you.

Are there trials for AF patients with heart failure?

Yes. Several UK trials specifically enrol patients with both AF and heart failure. These test combined management strategies including catheter ablation for AF in HF patients, rate vs rhythm control in HF, anticoagulation optimisation, and combined device therapy. Having both conditions can actually broaden your trial eligibility.

Cardiovascular Comparison Updated 27 May 2026

Atrial Fibrillation vs Heart Failure — Clinical Trial Comparison

Q: Are there trials for AF patients with heart failure?

Yes. Several UK trials specifically enrol patients with both AF and heart failure. These test combined management strategies including catheter ablation for AF in HF patients, rate vs rhythm control in HF, anticoagulation optimisation, and combined device therapy. Having both conditions can actually broaden your trial eligibility.

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Atrial Fibrillation

Irregular rapid heart rhythm

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Heart Failure

Heart cannot pump blood effectively

Atrial fibrillation (AF) and heart failure are the two most common heart conditions in UK adults, and they frequently co-occur. AF can cause heart failure through sustained rapid heart rates, while heart failure can trigger AF by stretching the atria. Their trial landscapes are both extensive but focus on very different interventions — rhythm control and anticoagulation for AF, versus pump function and fluid management for heart failure.

Key Differences at a Glance

Feature	Atrial Fibrillation	Heart Failure
Core problem	Electrical — chaotic atrial electrical activity, irregular ventricular response	Structural/functional — reduced pump function (HFrEF) or stiff filling (HFpEF)
UK prevalence	~1.5 million diagnosed (many more undiagnosed)	~1 million diagnosed; ~920,000 in UK
Key symptoms	Palpitations, irregular pulse, shortness of breath, fatigue, dizziness	Breathlessness, ankle swelling, fatigue, exercise intolerance, orthopnoea
Types	Paroxysmal, persistent, permanent	HFrEF (EF <40%), HFmrEF (41–49%), HFpEF (≥50%)
Major risk	Stroke (5× increased risk)	Hospitalisation, death, progressive pump failure
Key diagnostic	ECG, Holter monitor, echocardiogram	Echocardiogram (EF), BNP/NT-proBNP, cardiac MRI

Clinical Trial Availability

Trial Aspect	Atrial Fibrillation	Heart Failure
UK trials actively recruiting	40–60 studies	60–80 studies
Most common trial phase	Phase 2–3	Phase 2–4
Top interventions tested	Catheter ablation (PFA), LAA closure, anticoagulants, mapping technology	SGLT2 inhibitors, ARNI, vericiguat, omecamtiv mecarbil, device therapy
Device trials	Ablation catheters, LAA occluders, wearable monitors	ICDs, CRT, LVADs, implantable haemodynamic monitors
Drug trials	Factor XIa inhibitors, antiarrhythmic drugs	SGLT2 inhibitors (dapagliflozin, empagliflozin), ARNI, soluble guanylate cyclase stimulators
HFpEF-specific trials	N/A	Growing rapidly — historically undertreated population

Exciting Emerging Treatments

Atrial Fibrillation Trials

Pulsed field ablation (PFA) — non-thermal tissue-selective ablation with fewer complications
Factor XIa inhibitors (abelacimab, milvexian) — anticoagulants with potentially lower bleeding risk than DOACs
AI-guided ablation mapping — machine learning identifying optimal ablation targets
Next-gen LAA closure devices — less invasive alternatives to lifelong anticoagulation
Wearable AF detection and early intervention — smartwatch-triggered treatment pathways

Heart Failure Trials

SGLT2 inhibitors for all EF ranges — dapagliflozin and empagliflozin transforming HF treatment regardless of diabetes status
Vericiguat (soluble guanylate cyclase stimulator) — for worsening heart failure events
Cardiac myosin activators (omecamtiv mecarbil) — improving heart contraction without increasing oxygen demand
Implantable haemodynamic monitors — preventing hospitalisation through early detection of decompensation
Gene therapy for heart failure — targeting SERCA2a and other molecular pathways

💡 Have both AF and heart failure? Combined trials exist

Up to 40% of heart failure patients also have AF. Several UK trials specifically enrol this combined population, testing whether catheter ablation improves heart failure outcomes, optimal rate vs rhythm control strategies, and combined device approaches. Having both conditions significantly increases your trial eligibility — ask your cardiologist about combined AF-HF studies.

Eligibility Differences

Atrial Fibrillation Trial Criteria

AF type (paroxysmal, persistent, permanent) — most ablation trials target specific types
CHA₂DS₂-VASc score for stroke risk stratification
Symptom burden (EHRA score) — some trials require symptomatic AF
Left atrial size and duration of AF for ablation trials
Anticoagulation status and bleeding risk

Heart Failure Trial Criteria

Ejection fraction category: HFrEF (EF <40%), HFmrEF (41–49%), HFpEF (≥50%) — trials target specific categories
NYHA class (I–IV) — symptom severity classification
BNP/NT-proBNP levels — biomarker confirming heart failure severity
Recent heart failure events (hospitalisation, IV diuretics) for worsening HF trials
Stable optimised background therapy — most trials require patients on guideline-directed medical therapy

💓 AF Trials

Find actively recruiting atrial fibrillation clinical trials across the UK

View AF Trials

💔 Heart Failure Trials

Find actively recruiting heart failure clinical trials across the UK

View Heart Failure Trials