Pulsed Electromagnetic Fields Heal Heart Attacks in Mice and Pigs Without Surgery

Ischemic heart disease remains the world's leading killer, and standard reperfusion therapies—stenting and bypass surgery—are unsuitable for a significant subset of patients or are complicated by reperfusion injury and restenosis. This study sought preclinical validation for pulsed electromagnetic field (PEMF) therapy as a noninvasive, drug-free adjunct after myocardial infarction (MI).

Using permanent ligation of the left anterior descending coronary artery in both mice and Bama miniature pigs, the researchers applied 30 Hz, 3.0 mT PEMF for 45 minutes daily—14 days in mice and 28 days in pigs. Serial echocardiography tracked ejection fraction (LVEF), fractional shortening (LVFS), and ventricular volumes in mice, while cardiac MRI with late gadolinium enhancement (LGE) assessed infarct extent and wall motion in pigs. In mice, PEMF-treated animals showed significantly higher LVEF and LVFS alongside lower LVEDV and LVESV compared to untreated MI controls. Masson trichrome staining confirmed a meaningful reduction in scar size at day 14. In pigs, CMR demonstrated fewer LGE-positive segments and improved wall motion score index in the PEMF group versus controls at both 14 and 28 days post-MI.

Mechanistic work spanned in vitro and in vivo approaches. Macrophages exposed to the inflammatory post-MI milieu showed reduced pro-inflammatory cytokine output under PEMF. Cardiomyocyte survival improved, and cardiac fibroblasts secreted less collagen. At the molecular level, PEMF suppressed the TLR4/MyD88/NF-κB signaling axis—a key driver of post-infarct inflammation—and the TGF-β1/SMAD3 pathway responsible for maladaptive fibrosis. Crucially, adding the TLR4 agonist RS09 reversed PEMF's anti-inflammatory effects, and the TGF-β agonist SRI-011381 blunted its antifibrotic benefit, providing direct pathway-level evidence. Even in TLR4 knockout mice or after pretreatment with the NF-κB inhibitor PDTC, PEMF still conferred cardiac benefit, suggesting complementary or parallel mechanisms beyond TLR4 alone.

Safety profiling was thorough for a preclinical study. Liver and kidney function biomarkers remained normal throughout treatment in both species. Gut microbiota analysis in pigs showed no emergence of harmful bacterial populations, addressing a concern relevant to long-term electromagnetic exposure. No adverse events were reported in any animal.

The translational arc from mouse to pig is noteworthy: porcine cardiac anatomy and physiology closely mirror humans, and the use of CMR—the clinical gold standard for infarct assessment—strengthens relevance. These data collectively support PEMF as a candidate noninvasive physical therapy worth advancing toward human trials in post-MI and broader ischemic heart disease populations.