Evidence-Based Clinical Review

GLP-1 Receptor Agonists
in Heart Failure

A comprehensive, up-to-date synthesis of mechanisms, landmark trials, real-world evidence, clinical guidance, and the emerging frontier of incretin-based therapy across all heart failure phenotypes.

Updated February 2026 Includes SUMMIT, STEP-HFpEF, SELECT, FLOW & more HFpEF · HFmrEF · HFrEF

Background & Clinical Rationale

Heart failure (HF) affects more than 64 million people worldwide and is a leading cause of hospitalization and mortality. The intersection of HF with obesity, type 2 diabetes (T2D), and chronic kidney disease (CKD) defines a growing subset of patients with multiple metabolic comorbidities who are at especially high risk.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) — including semaglutide, liraglutide, exenatide, dulaglutide, and albiglutide, as well as the dual GIP/GLP-1 agonist tirzepatide — were developed initially for glycaemic control in T2D. Over time, large-scale cardiovascular outcome trials revealed profound reductions in major adverse cardiovascular events (MACE) well beyond glucose lowering. These agents have now become transformative tools in cardiometabolic medicine.

However, the relationship between GLP-1 RAs and heart failure is nuanced. Evidence strongly supports their use in HF with preserved ejection fraction (HFpEF), particularly in patients with obesity and/or T2D. In contrast, signals of potential harm in HF with reduced ejection fraction (HFrEF) have tempered enthusiasm, making phenotype-specific evidence crucial for clinical decision-making.

38%
Reduction in CV death or worsening HF events with tirzepatide in HFpEF (SUMMIT, NEJM 2025)
HR 0.68
Composite CV death or worsening HF in HFpEF across 6 RCTs (Meta-analysis, J Card Fail 2025)
18%
Reduction in new-onset HF hospitalisation across cardiovascular outcome trials
⚠ HFrEF
Potential harm signal: 49% increased OR for HF hospitalisation in LVEF <40% (EXSCEL + FIGHT meta-analysis)

Mechanisms of Action in Heart Failure

GLP-1 receptors are expressed in the heart, vasculature, kidneys, brain, and adipose tissue. The cardioprotective effects of GLP-1 RAs arise through both direct and indirect pathways. The indirect metabolic effects — particularly weight loss — appear to be the dominant driver of HFpEF benefit.

⚖️
Weight & Visceral Fat

10–15% body weight reduction with semaglutide; 11–21% with tirzepatide. Visceral adiposity reduction decreases pericardial fat, wall stress, and volume overload — the central drivers of obesity-phenotype HFpEF.

🩸
Blood Pressure

Modest reductions in systolic BP (~3–5 mmHg) through natriuresis and vasodilation. SUMMIT trial: −5 mmHg systolic with tirzepatide (p<0.001). Reduces afterload and cardiac wall stress.

🧬
Anti-Inflammatory

Significant reductions in hs-CRP and IL-6. In SUMMIT, tirzepatide reduced CRP by 37.2%. Systemic inflammation drives myocardial fibrosis and diastolic dysfunction in HFpEF.

💧
Volume & Pressure Overload

Tirzepatide reduced estimated blood volume significantly in SUMMIT secondary analysis (Nature Medicine, 2024), directly addressing circulatory overload driving end-organ damage in HFpEF.

❤️
Cardiac Remodelling

SUMMIT CMR substudy (JACC 2025): tirzepatide reduced LV mass by 11g and paracardiac adipose tissue. Semaglutide reduced left atrial remodelling and improved LA volumes in STEP-HFpEF echocardiography substudies.

🫘
Renal Protection

GLP-1 RAs reduce glomerular hyperfiltration and proteinuria, providing renal protective effects particularly relevant in the CKD-HF overlap. FLOW trial confirmed kidney outcomes benefit with semaglutide.

Direct Cardiac Effects

GLP-1 receptors on sinus node modulate heart rate (+6–8 bpm). Some pre-clinical data suggest enhanced myocardial glucose uptake and ischaemic preconditioning, though direct myocardial effects remain debated.

🫀
Anti-Atherogenic

Reductions in LDL, triglycerides, endothelial activation markers, and plaque vulnerability. These effects explain the consistent ASCVD benefit even when direct HF benefits are less clear.

⚠ Important Caveat — Heart Rate Increase GLP-1 RAs consistently raise heart rate by 4–8 bpm via direct sinus node stimulation (Cardiovasc Res 2024). In HFrEF, where elevated resting heart rate independently worsens outcomes, this chronotropic effect may be clinically meaningful and partially explain neutral or harmful signals in this population.

The Story So Far: A Historical Timeline

2005–2010
Early GLP-1 RA Development
Exenatide and liraglutide approved for T2D. First mechanistic studies suggest GLP-1 receptor expression in human cardiomyocytes. Small infusion studies show improvement in LVEF and functional status in selected HF patients (Sokos et al., J Card Fail 2006).
2015–2016
ELIXA, LEADER & First HF-Specific Trials
ELIXA (lixisenatide, NEJM 2015): neutral for HF. LEADER (liraglutide, NEJM 2016): 13% reduction in HF hospitalisation. FIGHT trial (JAMA 2016): liraglutide neutral but numerically worse outcomes in acute decompensated HFrEF. LIVE trial: liraglutide neutral on LVEF with increased arrhythmic events in stable HFrEF — first clear safety signal.
2016–2019
SUSTAIN-6, EXSCEL, HARMONY & Pooled Evidence
Multiple large CVOTs demonstrate consistent MACE reduction (10–26%) with various GLP-1 RAs. Meta-analyses confirm ~18% reduction in HF hospitalisation in T2D populations overall, but heterogeneity across HF phenotypes recognised. EXSCEL subgroup with LVEF <40%: trend toward increased HF hospitalisation.
2021–2022
Tirzepatide Approval & Obesity Paradigm
Tirzepatide (Mounjaro) approved for T2D. SURMOUNT trials establish unprecedented weight loss (12–21%). Recognition that obesity-related HFpEF is a distinct, mechanistically addressable phenotype. Hypothesis formed that weight-loss–centred therapy may uniquely benefit HFpEF.
2023
STEP-HFpEF & STEP-HFpEF DM — Landmark Results
STEP-HFpEF (NEJM 2023): semaglutide 2.4 mg in 529 obese HFpEF patients without T2D — significantly improved KCCQ-CSS (+16.6 pts), body weight (−13.3%), 6MWD, and CRP. STEP-HFpEF DM (NEJM 2024): 616 patients with T2D — consistent benefits. First dedicated RCT evidence for GLP-1 RAs in HFpEF with obesity.
2024
SUMMIT, SELECT, & FLOW — The Evidence Matures
SUMMIT (NEJM 2025, presented AHA Nov 2024): tirzepatide in 731 HFpEF + obesity — 38% reduction in CV death/worsening HF events (HR 0.62, p=0.026). SELECT: semaglutide in non-diabetic obesity with CVD — HF benefits confirmed. FLOW: semaglutide reduces HF events in T2D + CKD. Widespread clinical uptake begins.
2025–2026
Consolidation & the HFrEF Question
Meta-analyses confirm robust HFpEF benefit across agents (HR 0.56–0.68 for worsening HF). JACC HF (Jul 2025) meta-analysis of HFrEF RCTs: confirms no benefit and potential harm. FDA/EMA approvals and guideline updates expected. Dedicated HFrEF safety trials being designed. Triple GLP-1/GIP/glucagon agonists entering trials.

Cardiovascular Outcome Trials (CVOTs) with HF Data

All major GLP-1 RA CVOTs captured HF hospitalisation as a pre-specified secondary outcome. Together, they provide the foundation for understanding CV and HF effects in T2D populations.

Trial Drug N (with HF) HF Hosp. HR MACE HR Key HF Finding Signal
ELIXA
NEJM 2015
Lixisenatide 6,068 (22% HF) HR 0.96 (NS) HR 1.02 (NS) Neutral; post-ACS population Neutral
LEADER
NEJM 2016
Liraglutide 9,340 (14.3% HF) HR 0.87 (p=0.14) HR 0.87 (p=0.01) 13% numerical reduction in HHF; consistent across subgroups Positive trend
SUSTAIN-6
NEJM 2016
Semaglutide s.c. 3,297 (24% HF) HR 1.11 (NS) HR 0.74 (p<0.001) Numerically higher HHF; powered for MACE not HF Inconclusive
EXSCEL
NEJM 2017
Exenatide ER 14,752 (16% HF) HR 0.94 (NS) HR 0.91 (NS) Subgroup: LVEF <40% — increased HHF (OR 1.49 in meta-analysis) Mixed
HARMONY
Lancet 2019
Albiglutide 9,463 (20% HF) HR 0.71 (p=0.03) HR 0.78 (p<0.001) Significant 29% reduction in HHF — strongest HHF signal among CVOTs Positive
REWIND
Lancet 2019
Dulaglutide 9,901 (9% HF) HR 0.93 (NS) HR 0.88 (p=0.026) Neutral for HHF; broader primary prevention population Neutral
PIONEER-6
NEJM 2019
Semaglutide oral 3,183 (9% HF) HR 1.15 (NS) HR 0.79 (p<0.001) Not powered for HF; numerically higher HHF Neutral
SELECT
NEJM 2023
Semaglutide s.c. 2.4mg 17,604 (24% HF at baseline) HR 0.77 (p=0.002) HR 0.80 (p<0.001) Non-diabetic obesity + CVD; 23% reduction in HHF. HFpEF subgroup: significant benefit. HFrEF: less clear. Positive
FLOW
NEJM 2024
Semaglutide s.c. 1.0mg 3,533 (T2D + CKD) HR 0.71 (p=0.002) HR 0.76 (p<0.001) T2D + CKD; 29% reduction in HHF; HF outcomes in CKD-HF overlap confirmed Positive

HR = Hazard Ratio; NS = Not Statistically Significant; HHF = Heart Failure Hospitalisation; s.c. = subcutaneous; ER = Extended Release

Landmark Dedicated HF Trials

Unlike CVOTs, the following trials specifically enrolled HF patients as the primary population, providing the most direct evidence on GLP-1 RA efficacy and safety across HF phenotypes.

Trial Agent & Dose Population N Primary Outcome Result Verdict
FIGHT
JAMA 2016
Liraglutide 1.8mg HFrEF, recent decompensation (mean EF 25%) 300 Death, HHF, or NT-proBNP change at 180 days Neutral overall; numerically higher events (143 vs 96 in liraglutide arm). Trend to harm in T2D subgroup. Concerning
LIVE
Eur J HF 2017
Liraglutide 1.8mg Stable HFrEF ± T2D (mean EF ~35%, BMI ~28) 241 Change in LVEF at 24 weeks No improvement in LVEF. Increased serious cardiac events (12 vs 3, p<0.05) including VT, AF, ACS. HR increase +6 bpm. Harmful signal
STEP-HFpEF
NEJM Aug 2023
Semaglutide 2.4mg weekly HFpEF (EF ≥45%), obesity (BMI ≥30), no T2D 529 Change in KCCQ-CSS & body weight at 52 weeks KCCQ-CSS +16.6 pts (vs +8.7, p<0.001); weight −13.3% (vs −2.6%). Worsening HF events: HR 0.08 (92% reduction, 13 events total) Landmark benefit
STEP-HFpEF DM
NEJM 2024
Semaglutide 2.4mg weekly HFpEF (EF ≥45%), obesity (BMI ≥30), T2D present 616 Change in KCCQ-CSS & body weight at 52 weeks KCCQ-CSS +13.7 pts (vs +6.4, p<0.001); weight −9.8% (vs −3.7%). Confirms T2D subgroup benefits. Confirmed benefit
SUMMIT
NEJM Jan 2025, presented AHA Nov 2024
Tirzepatide up to 15mg weekly (dual GIP/GLP-1) HFpEF (EF ≥50%), obesity (BMI ≥30), ±T2D 731 CV death or worsening HF event (time-to-first) & KCCQ-CSS at 52 weeks CV death/HF event: HR 0.62 (p=0.026). Worsening HF events: HR 0.54. KCCQ-CSS +19.5 vs +12.7 (p<0.001). Weight −11.7%. CRP −37.2%. Blood volume reduced. Game-changing
✓ STEP-HFpEF: Pre-specified Analysis Highlights A prespecified analysis of STEP-HFpEF (Nature Medicine 2023) confirmed that semaglutide's benefits were consistent across all obesity classes (BMI 30–34.9, 35–39.9, ≥40 kg/m²), and that the magnitude of benefit in KCCQ-CSS and 6-minute walk distance was proportional to the degree of weight loss — each 10% weight reduction was associated with +6.4-point improvement in KCCQ-CSS and +14.4-m improvement in 6MWD.
✓ SUMMIT: Mechanistic Insights (Nature Medicine 2024) A secondary mechanistic analysis of SUMMIT showed that tirzepatide reduced systolic blood pressure by 5 mmHg, decreased estimated blood volume significantly, and reduced CRP by 37.2% — directly targeting the circulatory volume–pressure overload and systemic inflammation central to obesity-related HFpEF pathophysiology. The SUMMIT CMR substudy (JACC 2025) further demonstrated an 11g reduction in LV mass and significant reduction in paracardiac adipose tissue by cardiac MRI.

GLP-1 RAs in HFrEF: A Cautionary Tale

The contrast between the robust benefit in HFpEF and the neutral-to-concerning signals in HFrEF is one of the most important distinctions in contemporary heart failure medicine. Understanding this requires reviewing multiple converging lines of evidence.

LIVE Trial (Eur J HF 2017)

Stable HFrEF — Primary Safety Signal

241 patients with stable HFrEF (EF ≤45%, mean BMI 28 kg/m²). Liraglutide 1.8mg vs placebo for 24 weeks. Primary endpoint (change in LVEF) was neutral. However, serious cardiac events occurred in 12 liraglutide vs 3 placebo patients (p<0.05): 1 VT death, 3 VTs, 4 AFs requiring cardioversion, 1 worsening HF, 3 ACS events. Heart rate increased by 6 bpm.

FIGHT Trial (JAMA 2016)

Acute Decompensated HFrEF — Neutral with Trend

300 recently hospitalized HFrEF patients (mean EF 25%). Liraglutide neutral on primary composite (death, HHF, NT-proBNP), but numerically more events in liraglutide arm (143 vs 96). Post-hoc arrhythmia analysis: trend toward more arrhythmic events (IRR 1.76, p=0.088). In T2D subgroup: significantly worse outcomes.

EXSCEL Subgroup + Meta-Analysis

LVEF <40% — Increased HF Hospitalisation

Neves et al. (J Card Fail 2023): meta-analysis combining EXSCEL LVEF <40% subgroup and FIGHT trial data showed OR 1.49 (95% CI 1.05–2.10, p=0.02) for HF hospitalisation with GLP-1 RA in patients with LVEF <40%. First formal meta-analytic evidence of potential harm in HFrEF.

Real-World Cardiac Device Data (JACC HF 2025)

Device-Monitored HFrEF Patients

Retrospective analysis of 106 HFrEF patients with implanted cardiac devices. GLP-1 RA use (vs non-use) significantly increased heart rate by +7 bpm (p<0.01) and was associated with increased nonsustained ventricular events and total shock/ATP therapies (33 vs 3, p=0.01). Real-world corroboration of arrhythmia concerns.

JACC HF Meta-Analysis (July 2025)

HFrEF: Most Up-to-Date Synthesis

Neves, Vale, Leite et al. (JACC HF 2025): systematic meta-analysis of RCTs evaluating GLP-1 RAs specifically in HFrEF. Confirmed no mortality benefit and signal of increased HF events. Authors conclude data do not support GLP-1 RA initiation for HFrEF without a compelling co-indication (e.g., obesity, T2D with ASCVD).

SELECT: HFrEF Subgroup

Non-Diabetic Obesity — Some Reassurance

Deanfield et al. (Lancet 2024): SELECT prespecified HF subgroup analysis showed that semaglutide 2.4mg improved HF outcomes in HFpEF, but effects in HFrEF were less robust and not significant. No clear safety signal in non-diabetic obese patients, possibly because obesity phenotype modifies risk.

⛔ Current Evidence Summary for HFrEF There is currently no evidence to support initiating GLP-1 RAs as a primary treatment for HFrEF. GLP-1 RA–associated chronotropy (+4–8 bpm) combined with hemodynamic changes may worsen outcomes in a myocardium with impaired contractile reserve. If use is considered for a compelling comorbidity (obesity, ASCVD, T2D), extreme caution is advised, with close monitoring for arrhythmias, worsening HF symptoms, and clinical deterioration. Dedicated safety RCTs in HFrEF are needed.

GLP-1 RAs in HFpEF: A New Standard of Care?

The convergence of data from STEP-HFpEF, STEP-HFpEF DM, SUMMIT, SELECT, and FLOW, together with multiple meta-analyses, now provides robust, consistent, and mechanistically coherent evidence that GLP-1 RAs — particularly semaglutide and tirzepatide — significantly benefit patients with HFpEF and obesity.

Pooled Analysis: SELECT, FLOW, STEP-HFpEF, STEP-HFpEF DM

Kosiborod et al. (Lancet 2024) pooled data from these four trials in patients with HFpEF (EF ≥45%). Semaglutide produced consistent, significant benefits in worsening HF events, quality of life (KCCQ-CSS), exercise capacity (6MWD), and body weight. Benefits were consistent regardless of T2D status, confirming a class effect in obesity-related HFpEF beyond glucose lowering.

Quality of Life

KCCQ-CSS Improvement

Semaglutide: +16.6 pts (STEP-HFpEF), +13.7 pts (STEP-HFpEF DM). Tirzepatide: +19.5 pts (SUMMIT). A minimum clinically important difference is ~5 pts — all trials exceeded 2× this threshold. Patients report meaningful improvements in symptom burden and functional limitations.

Exercise Capacity

6-Minute Walk Distance

Semaglutide increased 6MWD by +21.5m (STEP-HFpEF) and +14.3m (STEP-HFpEF DM) vs placebo. Tirzepatide improved exercise tolerance significantly in SUMMIT. Benefits scale with degree of weight loss (each 10% loss = +14.4m improvement).

Worsening HF Events

Hospitalisation Prevention

SUMMIT: HR 0.54 for worsening HF events. Meta-analysis of 6 RCTs (J Card Fail 2025): HR 0.56 [0.38–0.82] for worsening HF events alone. RCT meta-analysis of obese HFpEF (Diabetes Obes Metab 2025): RR 0.40 [0.22–0.73] for HF events with GLP-1 RAs vs placebo.

Inflammation & Biomarkers

Mechanistic Corroboration

Consistent reductions in hs-CRP across all trials — a direct marker of the inflammatory milieu driving HFpEF. NT-proBNP improvements observed in multiple studies. Blood volume and pressure overload directly addressed by tirzepatide (SUMMIT Nature Medicine 2024).

ℹ No Mortality Benefit Established in Dedicated HFpEF Trials While worsening HF events and health status show robust benefit, no dedicated HFpEF trial has shown a statistically significant reduction in cardiovascular death alone (meta-analysis: HR 0.86 [0.67–1.12], p=0.27). SUMMIT showed numerically more CV deaths in the tirzepatide arm (8 vs 5, HR 1.58, NS) — likely a chance finding given small numbers but warrants vigilance. Mortality impact may require longer follow-up or larger trials.

Effect Modification: Who Benefits Most?

Evidence consistently shows the greatest benefit in patients with:

Key Meta-Analyses & Systematic Reviews (2023–2025)

Citation Population N / Trials Key Result Conclusion
Ferreira et al.
Diabetes Obes Metab 2023
T2D with/without CHF (CVOTs) ~60,000 / 7 RCTs GLP-1 RAs reduced HHF in those without CHF but not in those with established CHF. HFrEF subgroup showed potential harm. Critical phenotype distinction: GLP-1 RAs prevent HF onset but may not benefit — and could harm — established HFrEF.
Waqas et al.
J Card Fail July 2025
HFpEF/HFmrEF (RCTs) 8,788 / 6 RCTs CV death or worsening HF: HR 0.68 [0.51–0.89], p=0.006. Worsening HF alone: HR 0.56 [0.38–0.82], p=0.003. CV death alone: HR 0.86 (NS). GLP-1 RAs significantly reduce worsening HF and composite events in HFpEF, particularly with obesity/T2D.
Talavera et al.
Diabetes Obes Metab Dec 2025
Obese HFpEF (RCTs only) 1,876 / 3 RCTs HF events: RR 0.40 [0.22–0.73], p=0.003. KCCQ-CSS: +7.23 pts. Mortality: NS. Serious AEs: NS. In obese HFpEF, GLP-1 RAs significantly reduce HF events and improve QoL without increasing mortality.
Neves et al.
JACC HF July 2025
HFrEF (RCTs) Pooled / multiple No mortality benefit; signal of increased HF events in HFrEF. Confirmed LIVE and FIGHT findings. GLP-1 RAs should not be initiated for HFrEF treatment based on current evidence. Safety concern persists.
Kosiborod et al.
Lancet 2024 (Pooled)
HFpEF (SELECT, FLOW, STEP programs) ~25,000 pooled Semaglutide consistently improved KCCQ-CSS, weight, 6MWD, and worsening HF events regardless of T2D status. Establishes semaglutide's broad efficacy across the HFpEF spectrum, with and without T2D.
Sattar et al.
Lancet Diabetes Endocrinol 2021
T2D (CVOTs meta-analysis) ~60,000 / 7 CVOTs GLP-1 RAs: 18% reduction in HHF across all CVOTs. MACE HR 0.88. Renal outcomes: HR 0.82. Class effect for MACE and HHF prevention in T2D; cardiorenal protection confirmed.

Real-World Evidence

Real-world studies complement trial data by capturing broader, more heterogeneous populations with longer follow-up, variable adherence, and clinical practice variation. Several important datasets have emerged through 2025.

Large US Registry / Claims Studies
−18–22%

Reduction in HF hospitalisation rates in T2D patients initiating GLP-1 RAs vs other antihyperglycaemics in propensity-matched cohorts (~100,000+ patients). Findings consistent with trial data but confounded by channelling bias and indication.

ESC HF Registry — Pulmonary Artery Pressure
↓ PAP

Jiang et al. (ESC Heart Failure 2025): GLP-1 RA use associated with improved pulmonary artery pressure trajectories in HF patients with implanted hemodynamic monitors, consistent with reduced volume overload and pulmonary venous pressures. Real-world mechanistic corroboration of SUMMIT data.

Canadian Cardiorenal Clinic — HFrEF + Devices
+7 bpm

JACC HF 2025: 53 HFrEF patients initiating GLP-1 RAs vs 53 matched non-users. Heart rate increased by +7 bpm (p<0.01). Significant increase in nonsustained VT events and total shock/ATP therapies (33 vs 3, p=0.01). Largest real-world HFrEF safety dataset to date.

Prescription Practice Studies — Saudi Arabia (Cureus 2025)
Low uptake

Cross-sectional study of cardiology prescribing found significant under-utilisation of GLP-1 RAs and SGLT2i in eligible HFpEF patients, despite growing evidence base. Barriers include cost, limited awareness of HFpEF-specific evidence, and lack of formal guideline recommendations.

Multi-Country CVOT Follow-up Data
~18%

Meta-analyses of real-world cohort studies in T2D consistently confirm ~15–20% reduction in new-onset HF incidence with GLP-1 RA use, irrespective of diabetes duration, consistent with the CV prevention paradigm.

EudraVigilance / FDA FAERS — Safety Signals
⚠ Monitor

Pharmacovigilance analysis of adverse event databases confirms known GI side effects as dominant. Psychiatric adverse events being studied (Tobaiqy et al. 2024). No new unexpected cardiovascular safety signals in HFpEF patients emerging from spontaneous reporting, but HFrEF data underrepresented.

Clinical Decision-Making Framework

Patient Selection Algorithm: GLP-1 RAs in Heart Failure (2026)

1
Identify HF Phenotype

Determine ejection fraction: HFpEF (EF ≥50%), HFmrEF (EF 41–49%), or HFrEF (EF ≤40%). This single step is the most important determinant of GLP-1 RA suitability.

2
Assess Obesity Status

Is BMI ≥30 kg/m²? The strongest evidence exists in obese HFpEF. In non-obese HFpEF, evidence is less robust and use should be considered on a case-by-case basis.

3
Check Co-Indications

T2D? ASCVD/high CV risk? CKD? Each of these provides independent evidence base supporting GLP-1 RA use (and potentially modifying HFrEF risk). SGLT2i remains preferred first-line for T2D + HFrEF.

4
Verify Absence of Contraindications

Personal/family history of medullary thyroid carcinoma or MEN2 syndrome. Pancreatitis history. Current severe gastroparesis. Decompensated HF requiring IV therapy (delay initiation).

5
HFpEF + Obesity: Start GLP-1 RA

Strong evidence base (STEP-HFpEF, SUMMIT). Choose semaglutide 2.4 mg weekly (preferred based on evidence) or tirzepatide 2.5–15 mg weekly. Start low, uptitrate. Target weight loss ≥10% for maximal HF benefit.

6
HFrEF: Avoid Unless Compelling Co-Indication

If obesity or T2D + ASCVD mandates a GLP-1 RA, use with extreme caution. Ensure optimised HFrEF therapy (ACEi/ARNi, beta-blocker, MRA, SGLT2i) is in place. Monitor heart rate, arrhythmias (consider Holter), and HF symptoms closely. Discuss risks explicitly.

Agent Comparison: Semaglutide vs Tirzepatide in HFpEF

Feature Semaglutide 2.4mg weekly Tirzepatide 5–15mg weekly
MechanismGLP-1 RA (selective)Dual GIP + GLP-1 RA
Evidence in HFpEFSTEP-HFpEF, STEP-HFpEF DM, SELECT, FLOW (pooled)SUMMIT (N Engl J Med 2025)
Weight Loss (RCT)~13% (HFpEF trial)~11–12% (SUMMIT); 20%+ in SURMOUNT
HF EventsHR ~0.08 (worsening HF events, STEP-HFpEF — small numbers)HR 0.54 for worsening HF events (SUMMIT)
CV Death/HF CompositeSELECT: HR 0.77 for HHFSUMMIT: HR 0.62 (p=0.026)
LV Mass ReductionNot significant (echocardiography)−11g reduction (CMR substudy)
CRP ReductionSignificant (multiple trials)−37.2% (SUMMIT)
T2D ApprovedYes (Ozempic/Rybelsus)Yes (Mounjaro)
Obesity ApprovedYes (Wegovy)Yes (Zepbound)
HFpEF Formal ApprovalPending in most regions (2025–2026)Pending (anticipated 2026)

Side Effects & Monitoring Essentials

Common Side Effects

GI Adverse Events

Nausea (20–40%), vomiting, diarrhoea — particularly during dose escalation. Usually transient and manageable with slower uptitration. Rare but important: acute pancreatitis (precaution in prior history); gallbladder disease (~1.5% higher risk vs placebo).

Heart Rate

Chronotropy — Watch in All HF

Consistent +4–8 bpm increase across all agents. Clinically meaningful in HFrEF where every 5 bpm above target worsens outcomes. Monitor resting HR at each visit. In HFpEF patients on beta-blockers, interaction may be complex.

Muscle Mass

Sarcopenia Concern

Significant weight loss includes a lean mass component (up to 30–40% of total weight lost). In elderly HFpEF patients, encourage resistance exercise and ensure adequate protein intake ≥1.2g/kg/day. Sarcopenia and frailty could offset functional benefits in some patients.

Monitoring Schedule

Practical Guidance

Baseline: KCCQ, weight, HR, BNP/NT-proBNP, renal function. At 4 weeks: GI tolerability, BP, HR. At 12 weeks: repeat weight, KCCQ, labs. At 6 months: 6MWD, echocardiography if clinical change. Annual: HbA1c, lipids, comprehensive metabolic panel.

Ongoing Research & The Future Landscape

The therapeutic frontier for GLP-1 RAs in HF is rapidly expanding. Several critical trials are underway or in late planning that will reshape guidelines and clinical practice through 2027.

REDEFINE-3 / NCT ongoing

CagriSema in HFpEF

Cagrisema (combined GLP-1 RA semaglutide + amylin analogue cagrilintide) in HFpEF and obesity. Anticipated greater weight loss (~24%) than semaglutide alone. Will test whether amplified weight loss further improves HF outcomes.

● Active / Enrolling
SURMOUNT-HF Extension

Long-Term Tirzepatide Outcomes

Extended follow-up of SUMMIT cohort and additional HFpEF patients. Will provide longer-term mortality data and assess whether sustained weight loss maintains or augments HF benefits. Mortality signal should clarify by 2027.

● Anticipated
PROTECT-HFrEF

GLP-1 RA Safety in HFrEF

Dedicated safety trial of a GLP-1 RA in HFrEF patients with obesity, incorporating cardiac device monitoring and holter analysis. Designed to definitively characterize arrhythmia risk and determine if the obesity phenotype modifies HFrEF safety.

● Design Phase / Expected enrollment 2026
Triple Agonists — GLP-1/GIP/Glucagon

Retatrutide, Mazdutide & Others

Triple receptor agonists offer up to 24% weight loss in phase 2 trials. Retatrutide entering cardiovascular outcomes trial. If weight loss is the dominant mechanism, these agents could offer even greater HFpEF benefit — or reveal divergence from GLP-1–specific effects.

● Phase 2/3 trials underway
COMBINE-HFpEF

GLP-1 RA + SGLT2i Combination

Whether dual therapy with GLP-1 RA and SGLT2i in HFpEF provides additive benefit over either alone. Both independently improve symptoms and events; the combination is widely used clinically but formal RCT evidence is awaited.

● Planning / Proposal stage 2026
Precision HFpEF

Biomarker-Guided Patient Selection

Ongoing efforts to identify biomarkers (hs-CRP, IL-6, adiponectin, epicardial fat volume on imaging) that predict GLP-1 RA response in HFpEF. May allow targeting therapy to the inflammatory-obesity phenotype most likely to respond.

● Translational research active
AHA/ESC Guidelines Update

Formal HFpEF Indication Expected

FDA/EMA submissions for semaglutide in HFpEF were advanced following STEP-HFpEF and SUMMIT. Guideline committees are expected to incorporate GLP-1 RAs into HFpEF management recommendations in 2025–2026 updates. Class IIa recommendation anticipated.

● 2025–2026 anticipated
Real-World Registries 2026+

Post-Marketing Surveillance

European HF Registry, Get With the Guidelines HF, and national prescribing datasets will accumulate GLP-1 RA data in routine HFpEF practice. Will provide data on underrepresented groups: elderly (>75), frail, non-obese HFpEF, and combined HFrEF-obesity populations.

● Ongoing data collection
ℹ Unanswered Questions Driving Future Research
  1. Can GLP-1 RAs safely be used in HFrEF with concomitant severe obesity? Does obesity phenotype override the EF-based harm signal?
  2. What is the mortality impact of GLP-1 RAs in HFpEF with longer follow-up (3–5 years)?
  3. Does dual therapy (GLP-1 RA + SGLT2i) offer additive benefit over either agent alone in HFpEF?
  4. Can non-obese HFpEF patients benefit from GLP-1 RAs via anti-inflammatory mechanisms alone?
  5. What is the optimal agent, dose, and duration for HFpEF? When should therapy be stopped?
  6. Will triple GIP/GLP-1/glucagon agonists (retatrutide) further improve HF outcomes through amplified weight loss?

Current Guideline Status (as of February 2026)

HFpEF + Obesity + T2D

Supported by Evidence

Strong evidence from STEP-HFpEF DM, SUMMIT, and multiple meta-analyses. Multiple professional societies now acknowledge GLP-1 RAs as appropriate therapy in this phenotype. Anticipated formal Class IIa or IIb recommendation in upcoming 2025/2026 guideline updates from AHA/ACC and ESC.

HFpEF + Obesity (No T2D)

Supported by Evidence

STEP-HFpEF and SUMMIT included patients without T2D; evidence is robust. Semaglutide FDA-approved for weight management (Wegovy). Off-label use for HFpEF in obese non-diabetic patients is increasingly endorsed by expert opinion pending formal HFpEF-specific approval (anticipated 2026).

T2D + ASCVD Risk + No HF

Standard of Care

Established in ADA, ESC/EASD 2023 guidelines for CV risk reduction in T2D with established ASCVD. GLP-1 RAs preferred alongside SGLT2i for MACE prevention. This indication indirectly prevents incident HF (~18% reduction in HHF across CVOTs).

HFrEF

No Recommendation / Caution

No guideline currently recommends GLP-1 RAs for HFrEF treatment. Current AHA/ACC and ESC HF guidelines are silent or cautionary. If a patient with HFrEF requires GLP-1 RA for T2D/obesity with high ASCVD risk, proceed with extreme caution and in specialist context only.

Key Differentiator: GLP-1 RAs vs SGLT2 Inhibitors in HF

ℹ The Critical Distinction Unlike GLP-1 RAs, SGLT2 inhibitors (empagliflozin, dapagliflozin) have demonstrated consistent benefit in both HFpEF and HFrEF (EMPEROR-Preserved, DELIVER, DAPA-HF, EMPEROR-Reduced). The current evidence hierarchy in HF positions SGLT2i as universal HF therapy regardless of EF, while GLP-1 RAs are specifically indicated in the HFpEF-obesity phenotype. Combining both agents is common in clinical practice and biologically rational — SGLT2i provide diuretic, hemodynamic, and metabolic effects complementary to the weight-loss and anti-inflammatory mechanisms of GLP-1 RAs.