The QRS amplitude in the electrocardiogram is modified by pericardial fluid and its content of sodium chloride
Fuenmayor, A.J.; Vitale, D.; Villalobos, M.A.; Winterdaal, D.M.; Fuenmayor, A.M.; Dávila, D.
Acta Cientifica Venezolana 39(4): 336-339
1988
ISSN/ISBN: 0001-5504 PMID: 3270291 Document Number: 306476
The effects of pericardial fluid and its NaCl concentration on the electrocardiographic QRS complex size were studied in Wistar rats submitted to thoracotomy and pericardiotomy. A first electrocardiogram (ECG) was recorded for control and a second one after drying the epicardial surface. During the ECG continuous recording, the following solutions were added to the dry epicardium: dextrose in water 5% (DW5%) and NaCl in water 0.45%, 0.9%, 1.35% and 1.8% respectively. The QRS amplitude variation were expressed as percentages and were analyzed with a one-way variance analysis and linear and polynomial regression. It was found that: 1) Drying the pericardium causes a 20% reduction in QRS amplitude (p < 0.01). 2) Immediately after adding the solutions to this organ the QRS amplitude increases between 24% and 59% (p < 0.01). 3) With DW 5% the QRS amplitude increase is inferior to the one observed with the NaCl solutions (p < 0.05). 4) The 0.9% NaCl solution causes the largest increase in QRS amplitude (p < 0.05). A weak polynomial (parabolic) correlation was observed between the QRS amplitude variation and the NaCl correlation in pericardial fluid. These results suggest that the pericardial fluid and its NaCl concentration have a direct influence on the QRS amplitude and that this amplitude does not only depend upon the conductivity of the pericardial fluid.