Can Iron Deficiency Cause Palpitations?
Yes, iron deficiency can directly cause cardiac palpitations, and this occurs through multiple mechanisms even in the absence of anemia. 1
Mechanisms Linking Iron Deficiency to Palpitations
Iron deficiency causes palpitations through several interconnected pathways:
Compensatory cardiac response: When iron stores are depleted, the heart must compensate for reduced oxygen-carrying capacity by increasing heart rate and stroke volume, which patients perceive as palpitations 1, 2
Direct myocardial effects: Iron-deficient cardiac myocytes demonstrate abnormal electrophysiological properties, including decreased action potential overshoot and shortened action potential duration, creating substrates for arrhythmogenesis 3
Hyperdynamic circulation: Chronic iron deficiency creates a hyperdynamic circulatory state with decreased systemic vascular resistance, forcing the heart to work harder and potentially triggering palpitations 2
Clinical Significance in Different Patient Populations
Patients with Heart Failure
- Iron deficiency affects 40-70% of chronic heart failure patients and is recognized as an important comorbidity independent of anemia 1
- The European Society of Cardiology (2016) recommends evaluating iron status in all newly diagnosed heart failure patients (Class I, Level C recommendation) 1
- Iron deficiency in heart failure patients is associated with worse symptoms, reduced exercise capacity, and increased hospitalizations 1, 4
Patients with Coronary Artery Disease
- Up to 60% of patients with coronary artery disease have iron deficiency 5
- Iron deficiency is associated with poor clinical outcomes in this population, independent of anemia 4
General Population
- Iron deficiency anemia symptoms specifically include cardiac palpitations along with fatigue, reduced exercise capacity, and dizziness 1
- Both iron deficiency with and without anemia can cause functional impairments 6
Diagnostic Approach
When evaluating palpitations potentially related to iron deficiency:
- Measure ferritin and transferrin saturation (TSAT) simultaneously - these should be evaluated together, not in isolation 1
- Iron deficiency is defined as: ferritin <100 μg/L OR ferritin 100-299 μg/L with TSAT <20% in heart failure patients 1
- Do not rely on mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), or serum iron alone - these are unreliable markers 1
Treatment Considerations
For Patients with Cardiovascular Disease
- Intravenous iron is preferred over oral supplementation in heart failure patients with iron deficiency, as it bypasses hepcidin-mediated blockade of intestinal absorption 7
- The European Society of Cardiology gives a IIA recommendation for IV iron therapy in heart failure patients with reduced ejection fraction and iron deficiency 7
- IV iron improves exercise capacity, quality of life, and reduces hospitalizations in heart failure patients 1, 7
For Patients Without Cardiovascular Disease
- Oral iron supplementation is first-line: ferrous sulfate 324 mg (65 mg elemental iron) daily or twice daily between meals 7
- Consider alternate-day dosing if palpitations or other side effects occur with standard dosing 3
- Continue treatment for 2-3 months after hemoglobin normalization to replenish iron stores 7
Important Caveats
- Avoid erythropoiesis-stimulating agents in patients with mild to moderate anemia and heart disease - harms outweigh benefits 1, 2
- Monitor patients with pre-existing cardiac conditions more closely when starting iron supplementation 3
- Withhold IV iron during active infections as these patients were excluded from clinical trials 1
- Iron deficiency should prompt investigation for underlying causes, including screening for celiac disease and endoscopic evaluation for gastrointestinal bleeding in appropriate patients 6