Heart failure & cardiomyopathiesResearch article
Clinical and experimental insights into hydroxychloroquine-associated electrical abnormalities and cardiomyopathy
- retrospectively analysed
- endomyocardial biopsy with transmission electron microscopy
- in vitro hiPSC-CM experiments
Authors' conclusion
Hydroxychloroquine therapy was associated with electrical abnormalities and cardiomyopathy. Experimental findings in hiPSC-CMs recapitulated key clinical features and provided biological support for the clinical observations.
Study context
- Population
- Hydroxychloroquine (HCQ)-treated patients
- Participants
- 261 HCQ-treated patients
- Comparison
- QTc and PR intervals pre-treatment vs on-treatment; hiPSC-CMs exposed to HCQ
Main finding
As reported in the abstract
HCQ discontinuation and clinically significant cardiotoxicity
HCQ discontinued
14 patients
Clinically significant cardiotoxicity (heart failure or isolated conduction abnormality), among the 14 who discontinued
3 patients (1.1% of the cohort)
Further findings
| Outcome | Values |
|---|---|
| QTc interval · pre-treatment vs on-treatment · increased; modest but statistically significant change | pre-treatment median 413 (IQR 399-426 ms) ms · on-treatment median 421 (IQR 407-440 ms) ms |
| PR interval · pre-treatment vs on-treatment · increased modestly | pre-treatment 148 (IQR 140-163 ms) ms · on-treatment 150 (IQR 142-168 ms) ms |
- QTc interval: P = 0.003
- PR interval: P = 0.041
Corrected field potential duration in hiPSC-CMs
- Prolonged with HCQ exposure; induced arrhythmic activity
- P = 0.013
- in vitro
Peak relaxation velocity in hiPSC-CMs
- Reduced, with concomitant attenuation of contractile function
- P < 0.01
- in vitro
Transmission electron microscopy
- Lamellar inclusions consistent with myelin-like bodies
Autophagy-related protein levels
- Significantly increased with HCQ exposure, suggesting impaired autophagic degradation
Original publication
Clinical and experimental insights into hydroxychloroquine-associated electrical abnormalities and cardiomyopathy. Eur Heart J Cardiovasc Pharmacother. Published 25 August 2026. doi:10.1093/ehjcvp/pvag063
Summarised from the published abstract; every number is checked against it