Pulseless Electrical Activity as the Initial Cardiac Arrest Rhythm: Importance of Preexisting Left Ventricular Function

Figures

• 

  Figure 1. Animal Group 1 and Group 2 protocols. A subset of each group underwent ischemic preconditioning described in Figure 2. EF indicates ejection fraction; LAD, left anterior descending coronary artery; LCx, left circumflex artery; and RCA, right coronary artery.

• 

  Figure 2. Protocols for group subset allocation for ischemic preconditioning (IPC) vs no IPC. A, Schematic of Groups 1 and 2 and Group subsets 2a and 2b. B, Ischemic preconditioning protocols for Groups 1b and 2b. Group 1b underwent preconditioning using transient occlusions of the proximal left anterior descending coronary artery (LAD), whereas group 2b underwent preconditioning using transient occlusions of the distal LAD because proximal LAD occlusion led to profound hypotension.

• 

  Figure 3. Blood pressure and ECG changes over time following balloon occlusion. A, Example of ventricular fibrillation (VF) onset in a Group 1 animal (mean onset for the group 23.5±9.0 minutes from occlusion). B, Example of onset of pulseless electrical activity (PEA) in a Group 2 animal (mean onset for the group was 1.7±1.1 minutes from occlusion). C, Example of PEA degenerating to VF in a Group 2a animal (mean onset for the VF after PE in Group 2a animals was 12.3±5 minutes from occlusion).

• 

  Figure 4. Initial rhythm and time to arrest following balloon occlusion. A, Initial arrest rhythm by prearrest left ventricular (LV) function. The initial arrest rhythm was ventricular fibrillation (VF) in those with normal prearrest ejection fraction (EF) and pulseless electrical activity (PEA) in those with low prearrest EF. Prearrest LV function was determined by transthoracic echocardiography before cardiac arrest. B, Time to VF, PEA, and VF after PEA following balloon occlusion. Time from occlusion to PEA was significantly shorter than the time from occlusion to VF. Animals in the VF after PEA column are the same animals as the PEA column.

• 

  Figure 5. Effect of ischemic preconditioning on Group 1 and Group 2 animals. A, Freedom from ventricular fibrillation (VF) in animals with normal left ventricular (LV) function following balloon occlusion. Group 1 subgroups, Group 1a and 1b, are compared demonstrating the effect of preconditioning. B, Freedom from VF after pulseless electrical activity (PEA) in animals with severe LV dysfunction following balloon occlusion. Group 2 subgroups, Group 2a and 2b, are compared demonstrating the effect of preconditioning. IPC indicates ischemic preconditioning.

• 

  Figure 6. Coronary reactive hyperemia. A, Time to peak coronary flow velocity during reactive hyperemia at baseline (52±15 seconds) and after ischemic preconditioning (IPC) (27±8 seconds) (P<0.0005, t test). B, Coronary flow vs time during reactive hyperemia at baseline. C, After IPC.

• 

  Figure 7. Translocation of PKCε (protein kinase C epsilon) to the particulate fraction with preconditioning. Western blot analysis was used to measure PKCε translocation to the mitochondria‐enriched particulate fraction (A). Densitometric comparison of PKCε signal between cytosolic and particulate fractions revealed the translocation of PKCε to the mitochondria‐enriched particulate fraction in the ischemic preconditioning (IPC) animals compared with no IPC controls (B). Mitochondria enrichment in the particulate fraction was measured using an antibody toward the β subunit of complex V adenosine triphosphate synthase β (ATPβ), showing equal enrichment in mitochondria in both no IPC and IPC samples (C). C indicates cytosolic fraction; DB71, direct blue 71 staining, a general protein staining to control for equal loading and transfer efficiency; and P, particulate fraction. Cyt indicates the term cytosolic fraction and Part indicates particulate fraction. An asterisk (*) indicates statistically signifant difference and more the asterisk count more statistical difference.

• 

  Figure 8. Ventricular fibrillation (VF) vs pulseless electrical activity (PEA) as the initial cardiac arrest rhythm. Prearrest left ventricular (LV) function is a major factor for initial cardiac arrest rhythm during acute coronary occlusion. Onset of PEA occurs sooner than VF. VF uniformly develops after ischemic PEA in the absence of preconditioning.