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High frequency electrocardiography of three orthogonal leads in dogs during a coronary artery occlusion
S Abboud1, J M Smith, B Shargorodsky
1Raymond and Beverly Sackler, Faculty of Exact Sciences, School of Physics and Astronomy, Tel Aviv University, Israel.
Insights
High-frequency electrocardiography detected changes in canine cardiac ischemia during coronary artery occlusion. Signal averaging revealed waveform alterations, indicating potential for non-invasive ischemia detection.
Area of Science:
- Cardiology
- Biomedical Engineering
- Veterinary Medicine
Background:
- Cardiac ischemia detection is crucial for timely intervention.
- Traditional electrocardiography has limitations in detecting subtle ischemic changes.
- High-frequency electrocardiography offers potential for enhanced sensitivity.
Purpose of the Study:
- To evaluate the efficacy of high-frequency electrocardiography (HFECG) and signal averaging in detecting canine cardiac ischemia.
- To analyze changes in QRS complex morphology during induced ischemia and reperfusion.
Main Methods:
- Cardiac ischemia was induced in dogs using a balloon occluding cuff on the left anterior descending coronary artery.
- Surface electrocardiograms were recorded using orthogonal bipolar leads (X, Y, Z).
- Signal averaging and band-pass filtering (150-250 Hz) were applied to high-frequency QRS complexes.
Main Results:
- Coronary ligation induced changes in high-frequency QRS complex morphology, including reduced amplitude zones.
- Reduced amplitude zones appeared during occlusion and disappeared upon reperfusion in most cases.
- The presence and width of these zones correlated with the ischemic state, potentially indicating slow conduction.
Conclusions:
- High-frequency QRS complex morphology analysis using signal-averaged electrocardiography can detect myocardial ischemia in dogs.
- This technique may provide a valuable non-invasive method for diagnosing cardiac ischemia.
- Further research could explore its clinical applicability in veterinary and human medicine.
Abstract:
The ability to detect cardiac ischemia in dogs was studied using high frequency electrocardiography and signal averaging technique. Ischemia was induced via a balloon occluding cuff placed around the left anterior descending coronary artery. Three surface orthogonal bipolar leads (X, Y, and Z) were recorded prior to inflation of the occluding cuff. The cuff was then inflated, causing a complete occlusion of the coronary artery. The surface electrocardiogram was recorded before and during ligation and during reperfusion. The recorded waveforms were divided into sequential 10-15 second segments representing different stages of the ischemic state and were aligned using cross-correlation scheme, averaged and band pass filtered between 150-250 Hz. Analysis of the filtered high frequency QRS complexes revealed that coronary ligation was accompanied by changes in waveform morphology including the appearance of zones of reduced amplitude. In seven out of ten experiments reduced amplitude zones were absent before the ligation, present during the occlusion and absent following reperfusion. In two experiments, reduced amplitude zones that were present prior to ligation became wider during occlusion. In one experiment no reduced amplitude zone was present during any stage of the experiment. Such zones may represent slow conduction in regions of the heart rendered ischemia during coronary ligation. Therefore, the morphology of the high frequency QRS complex, as determined by analysis of the signal averaged electrocardiogram, may provide useful information regarding the presence of myocardial ischemia.