Plasticizer Interaction With the Heart: Chemicals Used in Plastic Medical Devices Can Interfere With Cardiac Electrophysiology.
Level 5 - mechanism / opinion, no new human data
Ex vivo animal research (isolated rat hearts).
PubMed 31248280 · doi:10.1161/CIRCEP.119.007294
What was done
Optical mapping of transmembrane voltage and pacing protocols were performed on isolated, Langendorff-perfused rat hearts to evaluate the electrophysiological effects of acute exposure (30 minutes) to mono-2-ethylhexyl phthalate (MEHP) at a concentration equivalent to blood levels observed following clinical exchange transfusions, compared with controls.
What was found
Compared to controls, 30-minute MEHP exposure: - Increased atrioventricular node effective refractory period (147 vs 107 ms) and ventricular effective refractory period (117 vs 77.5 ms). - Prolonged action potential duration at slower pacing cycle lengths (reverse use dependence). - Steepened the plateau phase of the action potential duration restitution curve (slope 0.18 vs 0.06). - Prolonged late-phase repolarization leading to triangulation (70.3 vs 56.6 ms). - Slowed epicardial conduction velocity (35 vs 60 cm/s). - Inhibited Nav1.5 fast and late sodium currents with IC50 values of 874 µmol/L and 231 µmol/L, respectively.
Why it matters
This study demonstrates that acute exposure to MEHP at clinically relevant concentrations directly alters cardiac repolarization dynamics and slows conduction, providing a biological mechanism for potential arrhythmogenic risk from plastic medical devices.
Limits
The study was conducted ex vivo in isolated rat hearts rather than in living humans or intact animals, evaluated only acute 30-minute exposure, did not measure clinical arrhythmia outcomes in patients, and the abstract does not report the total sample size (n) of hearts tested.
Cited by
- context In rodent studies, exposure to the phthalate metabolite DBP decreases coronary flow, reduces cardiac contractility, slows heart rate, and slows electrical signal propagation in the heart.