Electrocardiographic changes during prolonged coronary artery occlusion in man: comparison of standard and high‐frequency recordings

Abstract

Detection of acute myocardial ischaemia using electrocardiographic methods is generally based on assessment of the ST segments in the standard 12-lead electrocardiogram (ECG). Several studies have also shown changes in high-frequency QRS components during acute ischaemia. The purpose of the present study was to determine the changes in high-frequency QRS components during prolonged percutaneous transluminal coronary angioplasty (PTCA) and to compare these changes with ST-segment deviations in the standard 12-lead ECG. The study population consisted of 19 patients receiving prolonged PTCA. Standard and high-resolution signal-averaged ECGs were recorded before and during balloon inflation. The high-resolution recordings were performed using bipolar X, Y and Z leads. The QRS complexes in the high-resolution signal-averaged ECGs were analysed within a bandwidth of 150-250 Hz. During inflation, significant reductions in high-frequency QRS components were observed (12-72%). Changes in the high-frequency QRS components were seen in four of the patients without ST-segments deviation in the standard ECG. The correlation between the ST-segment deviation and the reduction in high-frequency QRS components was weak (r = 0.27). Acute coronary artery occlusion produces changes in high-frequency QRS components, even in the absence of ST-segment deviation in the standard ECG. Further studies need to be carried out to evaluate whether analysis of high-frequency QRS components could provide a method for detecting myocardial ischaemia and give additional information to that available in the ST segment in the standard ECG.

High‐frequency QRS electrocardiogram

“…In humans, HF-QRS (150-250 Hz) has been recorded during PTCA (Pettersson et al, 1998(Pettersson et al, , 2000b. The results from these studies show that balloon-induced ischaemia leads to changes in HF-QRS RMS voltages in a majority of the patients.…”

Determination of the ability of high‐frequency ECG to estimate left ventricular mass in humans, determined by magnetic resonance imaging

“…It has previously been shown that diminution of HF-QRS is a more sensitive detector of acute myocardial ischaemia than changes in the ST segment of standard ECG (Abboud et al, 1987;Pettersson et al, 1998Pettersson et al, ,2000a. It has previously been shown that diminution of HF-QRS is a more sensitive detector of acute myocardial ischaemia than changes in the ST segment of standard ECG (Abboud et al, 1987;Pettersson et al, 1998Pettersson et al, ,2000a.…”

Assessment of myocardial ischemia through high frequency energy estimation over the time-frequency plane using wavelets

“…Different studies have reported high frequency energy changes (HFEC) during acute coronary occlusion. Abboud et al and Mor Avi et al [3,8] studied this phenomenon over human and animal models respectively; Petterson et al [4] could find HFEC even without ST deviations and obtained better sensitivity and specificity than the ST criteria. These studies of HFEC have used the 150-250Hz bandwidth, however, others research have included the bands of 80-300Hz [9], 20-30Hz, and 16-200 Hz [7], which shows that there is not a specific time-frequency region to evaluate HFEC.…”

“…Reversible ischemia was generally measured only during the repolarization process through ST segment deviation. Recent studies suggest that ischemic events can produce changes in highfrequency components of the QRS complex [3,4]. Because of its multi-resolution signal decomposition, wavelet analysis and specifically complex Morlet wavelet has been successfully used to characterize qualitatively patients prone to ventricular tachycardia (VT) [5,6] and short lasting events with the surface ECG before and after angioplasty [7].…”