Complementary and Alternative Medicine in Heart Failure

Definition

Complementary and alternative medicine (CAM) encompasses medical practices, products, or systems that do not conform to standard conventional medicine. In HF, >30% of patients use CAM, yet evidence for most agents is limited and drug-interaction risks are clinically significant. The 2023 AHA Scientific Statement is the primary evidence synthesis document for CAM in HF, dividing agents into those with potential benefit (Table 1) and those with potential harm or interactions (Table 2).

Key Concepts

Prevalence and Disclosure

• 30% of HF patients use CAM; 1 in 5 use herbal therapy annually sources/alt-medicine-hf-aha-2023 (very high)

• Patients do not disclose CAM use to clinicians approximately 50% of the time; <15% of cardiac patients have ever discussed CAM with their clinician sources/alt-medicine-hf-aha-2023 (very high)
• Receipt of care by a cardiologist is independently associated with higher CAM use sources/alt-medicine-hf-aha-2023 (very high)

Regulatory Context

• The Dietary Supplement Health and Education Act (DSHEA, 1994) exempts dietary supplements from FDA pre-marketing safety and efficacy review — manufacturers are responsible for product purity but FDA cannot require pre-market testing sources/alt-medicine-hf-aha-2023 (very high)
• Red yeast rice: 21% of commercial brands contain monacolin K at pharmacological (statin-equivalent) levels; some brands also contain citrinin (nephrotoxin) sources/alt-medicine-hf-aha-2023 (very high)

Potentially Beneficial Agents (Table 1)

Omega-3 Polyunsaturated Fatty Acids (PUFA) / Fish Oil

• GISSI-HF trial (n=6975, NYHA II–IV, 1 g EPA/DHA daily): modest reductions in CV hospitalizations (HR 0.92) and all-cause death (HR 0.91) vs placebo sources/alt-medicine-hf-aha-2023 (very high)
• VITAL-HF (1 g/day omega-3): no reduction in first HF hospitalisation, but significant reduction in recurrent HF hospitalization (HR 0.86, P=0.048) in secondary analysis sources/alt-medicine-hf-aha-2023 (very high)
• Dose-dependent AF risk: high-dose omega-3 (≥4 g/day) significantly increases AF incidence in two large trials; risk:benefit balance favours doses <4 g/day sources/alt-medicine-hf-aha-2023 (very high)
• AHA 2022 Guideline Class 2b, LOE B-R: Omega-3 PUFA supplementation for NYHA II–IV as adjunctive therapy to reduce mortality and CV hospitalizations sources/alt-medicine-hf-aha-2023 (very high)
• Note: Fish oil supplements are NOT recommended for primary cardiovascular prevention in otherwise healthy adults — different evidence base and context sources/diet-aha-2026 (very high)

Coenzyme Q10 (CoQ10)

• Q-SYMBIO trial (n=420): significant improvement in NYHA class and 50% reduction in MACE (HR 0.50, 95% CI 0.32–0.80, P=0.003); no change in 6MWD or NT-proBNP sources/alt-medicine-hf-aha-2023 (very high)
• Meta-analysis: reduction in all-cause mortality with supplementation
• Theoretical concern: statins may lower endogenous CoQ10 levels — additive interaction remains unproven clinically
• Overall: uncertain evidence; no definitive guideline recommendation sources/alt-medicine-hf-aha-2023 (very high)

L-Carnitine

• Meta-analysis (Song et al., 2017): significant improvement in NYHA class, LVEF, LV dimensions, stroke volume, diastolic filling indices, BNP/NT-proBNP, and mortality sources/alt-medicine-hf-aha-2023 (very high)
• Mechanism: fatty acid transport into mitochondria, reducing oxidative stress; no major HF therapy interactions

Thiamine (Vitamin B1)

• Loop diuretics deplete thiamine; relative deficiency common in HF (dietary factors, age, diuretic use) sources/alt-medicine-hf-aha-2023 (very high)
• IV thiamine in patients on chronic furosemide: LVEF improvement from 0.27 to 0.33 (P<0.01); meta-analysis: +3.28% net improvement in LVEF (95% CI 0.64–5.93%)
• No benefit without deficiency: Oral thiamine supplementation in ambulatory HFrEF without clinically significant deficiency → no improvement in QoL, 6MWD, NT-proBNP, or LVEF sources/alt-medicine-hf-aha-2023 (very high)
• Clinically: screen for thiamine deficiency in HF patients on long-term loop diuretics; supplement if deficient

Hawthorn (Crataegus spp.)

• Multiple small RCTs: improvement in exercise workload, exercise tolerance, HF symptoms (dyspnoea, fatigue, palpitations) sources/alt-medicine-hf-aha-2023 (very high)
• SPICE trial (>5000 patients, Crataegus extract WS 1442): Failed primary endpoint; adverse effects similar to placebo sources/alt-medicine-hf-aha-2023 (very high)
• Potential HARM in low LVEF: Subanalysis data indicate potential progression of HF in patients >18 years with NYHA II–III and LVEF ≤40%, especially LVEF ≤35%, over 6 months sources/alt-medicine-hf-aha-2023 (very high)
• Pharmacodynamic (not pharmacokinetic) interaction with digoxin — avoid combination

Yoga and Tai Chi

• Multiple RCTs: improvements in peak VO2, quality of life, exercise self-efficacy, 6MWD; reductions in BNP and serum inflammatory markers (IL-6, hsCRP) sources/alt-medicine-hf-aha-2023 (very high)
• Tai chi in HFpEF: higher 6MWD increase vs. aerobic exercise; improvement in mood and quality of life in HFrEF
• Mechanism: increased parasympathetic and decreased sympathetic activity
• Safe and well-tolerated as adjunctive therapies alongside GDMT sources/alt-medicine-hf-aha-2023 (very high)

Other Agents with Modest Evidence

• D-Ribose: Small RCTs show improvement in LV function, NYHA class, quality of life (ATP synthesis substrate)
• Acupuncture: Improvement in 6MWD and quality of life in small RCTs; no change in LVEF or peak VO2

Potentially Harmful or High-Interaction Agents (Table 2)

Licorice

• Glycyrrhetinic acid inhibits 11-β-hydroxysteroid dehydrogenase type 2 → apparent mineralocorticoid excess → sodium retention, hypertension, hypokalemia, cardiac arrest sources/alt-medicine-hf-aha-2023 (very high)
• Risk potentiated in patients receiving MRA; regulated under US Code of Federal Regulations
• Red licorice (not derived from licorice extract): no risk

Vitamin E ≥400 IU/day

• HOPE trial (n=9541): 13% increased risk of incident HF; 21% increased risk of HF hospitalisation vs. placebo sources/alt-medicine-hf-aha-2023 (very high)
• GISSI-Prevenzione: 50% increased risk of symptomatic HF in patients with LVEF <50%
• Moderate dietary vitamin E intake is safe; high-dose supplementation should be avoided

Grapefruit Juice

• Inhibits intestinal CYP-450 3A4 → increases bioavailability of drugs undergoing first-pass metabolism sources/alt-medicine-hf-aha-2023 (very high)
• Clinically significant interactions with common HF medications:
  • Amiodarone: increased bioavailability + additive QT prolongation risk
  • Carvedilol: +16% bioavailability
  • Losartan: decreased efficacy
  • Clopidogrel/ticagrelor: impaired antiplatelet effect (CYP2C19 inhibition)
  • Statins: increased plasma concentrations
  • QT-prolonging antiarrhythmics (dofetilide, sotalol, procainamide, disopyramide): additive risk
• High-risk population: older patients (>70 years) with multiple HF medications; ≥200 mL within 4 hours of affected medication is clinically significant; repeated ingestion cumulative
• Recommendation: avoid grapefruit juice in patients taking any of the above HF medications

L-Arginine (Harm Context)

• AVOID after acute MI: RCT demonstrated initiation post-infarction increases mortality in older patients; does not improve vascular stiffness or EF post-MI sources/alt-medicine-hf-aha-2023 (very high)

High-Dose Alcohol

• 10 drinks/week + hypertension + LV hypertrophy: increased new-onset AF (HR 1.60) sources/alt-medicine-hf-aha-2023 (very high)

• 6–7 drinks/day: alcoholic cardiomyopathy (reversible with abstention if not long-standing)
• See concepts/Alcoholic-Cardiomyopathy for full detail

St. John's Wort (Mentioned in Text)

• Potent CYP3A4 inducer → reduces plasma concentrations of warfarin, simvastatin, methadone, calcineurin inhibitors sources/alt-medicine-hf-aha-2023 (very high)

Caffeine

• 500 mg within 5 hours: no arrhythmia increase in regular coffee drinkers with HF (RCT n=51)
• Before cardiac perfusion imaging → false positives (adenosine antagonism)
• Moderate consumption (<300–400 mg/day) generally safe but avoid in patients prone to tachyarrhythmias

Other Harmful/High-Interaction Agents

• Gossypol: K⁺ depletion → hypokalemia → enhanced cardiac glycoside toxicity; avoid with digoxin or K⁺-wasting diuretics sources/alt-medicine-hf-aha-2023 (very high)
• Bitter orange: Sympathomimetic + CYP3A4 inhibitor → BP/HR increase; may cause angina
• Plant cardiac glycosides (Lily of the Valley, Oleander, Strophanthus, Ouabain): Narrow therapeutic index; potentiated by hypokalemia; arrhythmia toxicity
• Vitamin E interaction: Anticoagulant/antiplatelet at high doses → interacts with warfarin

Clinical Practice Principles

1. Clinicians should inquire about CAM at every encounter — shared decision-making model
2. Only omega-3 PUFAs have a guideline recommendation (Class 2b) for HF; all others lack sufficient evidence
3. A multidisciplinary team (cardiologist + pharmacist + nurse) improves CAM documentation and drug-interaction detection
4. Reporting CAM-related adverse reactions to FDA MedWatch or Health Canada MedEffect is encouraged

Contradictions / Open Questions

• Fish oil / omega-3 PUFA: disease-specific distinction: Omega-3 PUFA is AHA Class 2b for HF symptom management but NOT recommended for primary CVD prevention in healthy adults (diet-aha-2026). Both documents agree high doses (≥4 g/day) increase AF risk. Clinicians must distinguish between the HF-specific indication and general dietary advice. sources/alt-medicine-hf-aha-2023 (very high), sources/diet-aha-2026 (very high)
• Alcohol observational data vs. population-level recommendation: This statement notes low-to-moderate alcohol is associated with 10–23% lower HF incidence in observational data; however, randomised trial evidence (MR analyses) does not support cardioprotection from alcohol initiation, and the overall AHA dietary guidance recommends against initiating alcohol for health purposes. This is a confounding-driven discrepancy, not a true clinical contradiction. sources/alt-medicine-hf-aha-2023 (very high), sources/diet-aha-2026 (very high)
• Hawthorn: symptom benefit vs. potential harm in low LVEF: Multiple small RCTs demonstrate symptom improvement and exercise tolerance benefit, yet SPICE trial (>5000 patients) failed its primary endpoint, and post-hoc data suggest potential harm in LVEF ≤35%. Evidence is inconsistent across study sizes and populations. sources/alt-medicine-hf-aha-2023 (very high)
• CoQ10 Q-SYMBIO 50% MACE reduction without 6MWD or NT-proBNP change: The mechanism by which CoQ10 could halve MACE without changing NT-proBNP (a sensitive marker of HF severity) is unexplained and biologically implausible without a larger confirmatory trial — the result may reflect random variation in a single trial. sources/alt-medicine-hf-aha-2023 (very high)

Connections

• Related to entities/Heart-Failure — all CAM evidence reviewed in HF patients
• Related to entities/Atrial-Fibrillation — high-dose omega-3, hawthorn, grapefruit juice + antiarrhythmic interactions, licorice-induced hypokalemia
• Related to concepts/Heart-Healthy-Dietary-Patterns — fish oil supplements vs. dietary fish; alcohol population-level guidance
• Related to concepts/Alcoholic-Cardiomyopathy — high-dose alcohol as HF cause
• Related to concepts/Drug-Induced-Arrhythmia — grapefruit juice CYP3A4 interactions with QT-prolonging agents
• Related to concepts/HFpEF — tai chi in HFpEF; omega-3 PUFA across HF phenotypes
• Related to sources/alt-medicine-hf-aha-2023

Sources

• sources/alt-medicine-hf-aha-2023
• sources/diet-aha-2026