Optical mapping of sarcoplasmic reticulum Ca2+ in the intact heart: ryanodine receptor refractoriness during alternans and fibrillation
- Resource Type
- Authors
- Wang, Lianguo; Myles, Rachel C; De Jesus, Nicole M; Ohlendorf, Alex KP; Bers, Donald M; Ripplinger, Crystal M
- Source
- Circulation research, vol 114, iss 9
- Subject
- Time Factors
cardiac
Clinical Sciences
Action Potentials
In Vitro Techniques
Cardiorespiratory Medicine and Haematology
Sarcoplasmic Reticulum Calcium-Transporting ATPases
Caffeine
Receptors
Animals
Calcium Signaling
Excitation Contraction Coupling
Myocytes
Isoproterenol
Refractory Period
Ryanodine Receptor Calcium Release Channel
Adrenergic beta-Agonists
ventricular fibrillation
Electrophysiological
Voltage-Sensitive Dye Imaging
Perfusion
Sarcoplasmic Reticulum
Cardiovascular System & Hematology
Adrenergic
Artificial
cardiovascular system
Calcium
beta
Cardiac Pacing
Rabbits
arrhythmias
- Language
RationaleSarcoplasmic reticulum (SR) Ca(2+) cycling is key to normal excitation-contraction coupling but may also contribute to pathological cardiac alternans and arrhythmia.ObjectiveTo measure intra-SR free [Ca(2+)] ([Ca(2+)]SR) changes in intact hearts during alternans and ventricular fibrillation (VF).Methods and resultsSimultaneous optical mapping of Vm (with RH237) and [Ca(2+)]SR (with Fluo-5N AM) was performed in Langendorff-perfused rabbit hearts. Alternans and VF were induced by rapid pacing. SR Ca(2+) and action potential duration (APD) alternans occurred in-phase, but SR Ca(2+) alternans emerged first as cycle length was progressively reduced (217±10 versus 190±13 ms; P