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Effects of hemodialysis on body surface maps in patients with chronic renal failure
O Kinoshita1, G Kimura, S Kamakura
1Department of Medicine, National Cardiovascular Center, Osaka, Japan.
Insights
Hemodialysis alters electrocardiogram (ECG) readings, increasing QRS amplitude due to changes in thoracic conductivity and heart position, not cardiac issues. This impacts patients with chronic renal failure.
Area of Science:
- Cardiology
- Nephrology
- Biophysics
Background:
- Chronic renal failure (CRF) necessitates hemodialysis, a procedure with known cardiovascular implications.
- Electrocardiogram (ECG) changes during hemodialysis are not fully understood, particularly concerning non-ischemic factors.
Purpose of the Study:
- To investigate the impact of hemodialysis on ECG parameters using body surface mapping.
- To differentiate ECG changes related to hemodialysis from those caused by coronary artery disease (CAD).
Main Methods:
- 87-lead body surface electrocardiogram maps were recorded before and after hemodialysis in 38 CRF patients.
- Patients were categorized into coronary artery disease (CAD) and control groups.
- Analysis included QRS isopotential, isochrone, and QRS isointegral maps, measuring Peak R, Peak S, ventricular activation time (VATmax), and QRS duration (QRSd).
Main Results:
- In controls, hemodialysis increased Peak R and Peak S, and decreased VATmax, correlating negatively with body weight changes.
- In the CAD group, only Peak S increased significantly, also correlating negatively with body weight changes.
- Hemodialysis induced distinct changes in QRS isointegral maps, with increased positivity in controls and negativity in the CAD group on the anterior thorax.
Conclusions:
- Hemodialysis-induced increases in QRS amplitude are primarily attributed to altered thoracic conductivity and heart-chest wall position.
- These ECG changes are not indicative of myocardial ischemia or ventricular conduction delay in CRF patients undergoing hemodialysis.
Abstract:
To examine the effects of hemodialysis on the electrocardiogram, 87-lead body surface maps were performed in 38 patients with chronic renal failure, before and after hemodialysis. The patients were divided into two groups; 16 patients with coronary artery disease (CAD group), and 22 patients without ischemic heart disease (control group). Three maps were analyzed, QRS isopotential maps, isochrone maps, and QRS isointegral maps. Parameters measured were maximal R wave voltage (Peak R), minimal QRS wave voltage (Peak S), maximal ventricular activation time (VATmax) and QRS duration (QRSd). In the control group, Peak R and Peak S increased but VATmax decreased after hemodialysis. There were negative correlations between the changes of body weight and the changes in Peak R (r = -0.67, p < 0.01) and Peak S (r = -0.87, p < 0.001), although there were no correlations between changes in left ventricular diastolic dimension and the changes in Peak R and Peak S. In the CAD group, Peak S increased but Peak R and VATmax did not change significantly. There were negative correlations between the change of body weight and the change of Peak S (r = -0.73, p < 0.01). The most pronounced changes in mean QRS isointegral maps on hemodialysis were an increased magnitude of positivity in the control group and negativity in the CAD group on the anterior thorax. These findings suggested that the increase in the QRS amplitude after hemodialysis was influenced by the changes of the conductivity of extracardiac thorax and the relative heart position to the chest wall rather than myocardial ischemia or ventricular conduction delay.