Key Points
- This study aims to explore the relationship between early afterdepolarizations and changes in intracellular calcium concentration in ventricular myocytes.
- Isolated guinea pig ventricular myocytes were used and loaded with fluo-3 AM.
- Myocytes were paced at frequencies between 0.1 to 2 Hz while examining calcium transients.
- Comparative analysis was performed on calcium dynamics during early and delayed afterdepolarizations induced by isoproterenol.
- Calcium transients during early afterdepolarizations peaked higher than those during delayed afterdepolarizations (77% vs 64%, P < .001).
- Calcium transients during early afterdepolarizations were synchronous across the cell, while those during delayed afterdepolarizations displayed greater spatial heterogeneity.
- The time lag between calcium transient peaks was significantly longer during delayed afterdepolarizations (290 ms) compared to early afterdepolarizations (40 ms, P = .006).
Structured PICO
PPopulationIsolated patch-clamped guinea pig ventricular myocytes, loaded with fluo-3 acetoxymethyl ester (fluo-3 AM)
IInterventionIsoproterenol (100 nmol/L) with pacing at 0.1 to 2 Hz
OOutcomeSpatiotemporal changes in intracellular Ca2+ concentration ([Ca2+]i) related to early afterdepolarizations (EADs) and delayed afterdepolarizations (DADs)surrogate
Calcium transients during early afterdepolarizations are synchronous and higher in amplitude compared to the wave-like, spatially heterogeneous transients observed during delayed afterdepolarizations.