Influence of the skeletal muscle activity on time and frequency domain properties of the body surface ECG during evolving ventricular fibrillation in the pig.

Aim Of The Study: To evaluate influence of the skeletal muscle activity (SMA) on time and frequency domain properties of ECG during VF.

Materials And Methods: We studied the first 9min of electrically induced VF (N=7). We recorded Lead II ECG, 247 unipolar epicardial ventricular electrograms (UEGs) and 3 bipolar skeletal electromyograms (EMGs) near the positions of the ECG electrodes (sampling rate, 500Hz).

Near-infrared voltage-sensitive fluorescent dyes optimized for optical mapping in blood-perfused myocardium.

Background: Styryl voltage-sensitive dyes (e.g., di-4-ANEPPS) have been used successfully for optical mapping in cardiac cells and tissues.

Spatiotemporal relationship between intracellular Ca2+ dynamics and wave fragmentation during ventricular fibrillation in isolated blood-perfused pig hearts.

Normal "master-slave" relationship between the action potential (AP) and intracellular Ca2+ transient (Ca(i)T) is sometimes altered during ventricular fibrillation (VF). The nature of AP/Ca(i)T dissociation during VF and its role in inducing wavebreaks (WBs) remain unclear. We simultaneously mapped AP (RH237) and Ca(i)T (Rhod-2) during VF in blood-perfused pig hearts.

Three distinct phases of VF during global ischemia in the isolated blood-perfused pig heart.

Changes in ventricular fibrillation (VF) organization occurring after the onset of global ischemia are relevant to defibrillation and survival but remain poorly understood. We hypothesized that ischemia-specific dynamic instability of the action potential (AP) causes a loss of spatiotemporal periodicity of propagation and broadening of the electrocardiogram (ECG) frequency spectrum during VF in the ischemic myocardium. We recorded voltage-sensitive fluorescence of di-4-ANEPPS (anterior left ventricle, 35 x 35 mm, 64 x 64 pixels) and the volume-conducted ECG in six blood-perfused hearts during 10 min of VF and global ischemia.