Acute Changes in QRS Voltage in the Bipolar Leads on the Surface ECG Following Therapy in Acute Congestive Cardiac Failure Patients

Abstract

Following decongestive therapy in patients with acute heart failure, it has been observed that there is an increase in the QRS amplitude in the bipolar limb leads on the surface electrocardiogram (ECG). We wanted to study this phenomenon to identify any markers of improvements in heart failure. Patients with atrial flutter, atrial fibrillation, implanted permanent pacemaker, acute coronary syndrome and those treated with sodium nitroprusside were excluded. Net fluid loss over the course of diuresis was calculated as fluid lost-fluid administered. All patients had two standard 12-lead ECGs recorded at admission prior to starting diuresis and after conclusion of therapy which was at discharge. There were 59 patients. All were treated with decongestive therapy and observed over a period of 8 ± 3.2 days. The urine output following therapy was similar in both groups of patients. The left ventricular internal diameter in diastole (LVIDd) and left ventricular internal diameter in systole (LVIDs) were less in the group with increase in QRS amplitude (Group 2) compared to the group who did not show change in QRS amplitude (Group 1), 4.4 \(\pm\) 0.8 cm vs 4.9 \(\pm\) 0.8 cm, p = 0.036, and 3.1 \(\pm\) 0.5 cm vs 3.7 \(\pm\) 1.0 cm, p = 0.002. The ratio between the peak velocity blood flow in early (E wave) and late diastole (A wave) in group 2 was 1.2 \(\pm\) 0.7 compared to 1.7 \(\pm\) 1.0 in group 1, p = 0.087. The deceleration time (DT) was higher by 45.2 \(\pm\) 21.5 ms in group 2 compared to group 1 with no change in QRS amplitude, p = 0.04. Following decongestive therapy in a group of patients with heart failure, the QRS amplitude reflected in the limb leads improved significantly from pre-treatment values in the patients with less LV remodelling in terms of LV dilatation and LV diastolic dysfunction.