Electrical Activation During Ventricular Fibrillation in the Subacute and Chronic Phases of Healing Canine Myocardial Infarction

Abstract

During VF, in animals with subacute or chronic healing MI, (1) the size of activation wave fronts is larger, (2) the cycle length of VF is longer, (3) the conduction velocities are slower, and (4) the degree of organization is greater than in control animals. Thus, the characteristics of VF throughout the heart are altered by the presence of regional myocardial infarction. The implications of these findings for the initiation and maintenance of VF in the presence of different underlying myocardial substrates require further study.

Characteristics of ventricular fibrillation in relation to cardiac aetiology and shock success: A waveform analysis study in ICD-patients

“…The lower frequencies may be the result of ischemic cell damage and the presence of scar. In a mapping study in dog hearts with a previous MI, it was observed that during VF the mean size of activation wave fronts was larger than in controls 17 . Larger wave fronts may translate into a lower dominant (or fundamental) frequency of VF on the ECG, as was shown in a study analyzing the effect of ischemia on VF dynamics in rabbit hearts 18 .…”

Infarct Tissue Heterogeneity by Magnetic Resonance Imaging Identifies Enhanced Cardiac Arrhythmia Susceptibility in Patients With Left Ventricular Dysfunction

“…Infarcts can have marked spatial heterogeneity, with areas of necrosis interspersed with bundles of viable myocytes, particularly in the border zones and periphery of the infarct. [12][13][14] Tissue heterogeneity in these regions may create areas of slow conduction that generate the substrate for the development of lethal reentrant arrhythmias. 14 -16 In the present study, we examine the utility of ceMRI in identifying patients with increased vulnerability to ventricular arrhythmias.…”

Effects of the Location of Myocardial Infarction on the Spectral Characteristics of Ventricular Fibrillation

“…Several experimental studies have shown that the existence of an infarcted area may change the frequency content of local EGMs during VF. In a canine model of chronic MI, the cycle length of VF was longer and the degree of organization greater than in the control group 16 . In a similar experimental preparation, Jacobson et al 8 found no significant changes in the f d or in the fractional peak power at the f d peak, but demonstrated a significant reduction of the total and peak power in the infarcted animals.…”