TY - JOUR
T1 - Amplitude changes during ventricular fibrillation: A mechanistic insight
AU - Caldwell, Jane
AU - Caldwellf, Jane C.
AU - Burton, Francis L.
AU - Cobbe, Stuart M.
AU - Smith, Godfrey L.
PY - 2012
Y1 - 2012
N2 - Introduction: Clinically in ventricular fibrillation (VF), ECG amplitude, and frequency decrease as ischemia progresses and predict defibrillation success. In vitro ECG amplitude declines without ischemia, independent of VF frequencies. This study examines the contribution of cellular electrical activity and global organization to ECG amplitude changes during VF. Methods and Results: Rabbit hearts were Langendorff-perfused (40 mL/min, Tyrode's solution) and loaded with RH237. During VF ECG, and epicardial optical action potentials were recorded (photodiode array; 256 sites, 15 mm × 15 mm). After 60s of VF, perfusion was either maintained, global ischemia produced by low-flow (6 mL/min), or solution [K +] o raised to 8 mM. Peak-to-peak amplitude was determined for all signals. During VF in control, ECG amplitude decreased to a steady-state (~57% baseline), whereas in low-flow steady-state was not reached with the amplitude continuing to fall to 33% of baseline by 600 s. Optically, LV amplitude declined more than RV, reaching significance in control (LVvs. RV; 33 ±5 vs. 63 ±8%, p
AB - Introduction: Clinically in ventricular fibrillation (VF), ECG amplitude, and frequency decrease as ischemia progresses and predict defibrillation success. In vitro ECG amplitude declines without ischemia, independent of VF frequencies. This study examines the contribution of cellular electrical activity and global organization to ECG amplitude changes during VF. Methods and Results: Rabbit hearts were Langendorff-perfused (40 mL/min, Tyrode's solution) and loaded with RH237. During VF ECG, and epicardial optical action potentials were recorded (photodiode array; 256 sites, 15 mm × 15 mm). After 60s of VF, perfusion was either maintained, global ischemia produced by low-flow (6 mL/min), or solution [K +] o raised to 8 mM. Peak-to-peak amplitude was determined for all signals. During VF in control, ECG amplitude decreased to a steady-state (~57% baseline), whereas in low-flow steady-state was not reached with the amplitude continuing to fall to 33% of baseline by 600 s. Optically, LV amplitude declined more than RV, reaching significance in control (LVvs. RV; 33 ±5 vs. 63 ±8%, p
KW - ECG
KW - Floating microelectrode
KW - Ischemia
KW - Optical mapping
KW - Ventricular fibrillation
U2 - 10.3389/fphys.2012.00147
DO - 10.3389/fphys.2012.00147
M3 - Article
VL - 3
JO - Frontiers in Physiology
JF - Frontiers in Physiology
M1 - Article 147
ER -