Incidence of perioperative myocardial ischemia detected by different electrocardiographic systems
S Slogoff1, A S Keats, Y David
1Division of Cardiovascular Anesthesiology, Texas Heart Institute, Houston 77225-0345.
Insights
Different electrocardiographic (ECG) systems significantly impact the reported incidence of perioperative myocardial ischemia during coronary artery bypass grafting (CABG). The choice of ECG system and its bandwidth settings influence ischemia detection rates, highlighting the need for standardized protocols.
Area of Science:
- Cardiology
- Medical Instrumentation
- Anesthesiology
Background:
- Perioperative myocardial ischemia is a critical complication following coronary artery bypass grafting (CABG).
- Reported incidence rates of perioperative ischemia vary, potentially due to differences in electrocardiographic (ECG) monitoring systems.
Purpose of the Study:
- To evaluate how different ECG systems and bandwidth settings affect the reported incidence of perioperative myocardial ischemia.
- To compare ST-segment displacement and ischemia detection across various ECG monitoring devices in CABG patients.
Main Methods:
- Simultaneous ECG recordings using five different systems (Spacelabs, Marquette, Del Mar Holter) with varying bandwidths in 109 CABG patients.
- Utilized a common V5 lead for consistent signal acquisition across all systems.
- Analyzed ST-segment position and incidence of new myocardial ischemia using the 0.1-mV displacement criterion compared to preoperative ECG.
Main Results:
- ST-segment position was similar on systems adhering to American Heart Association (AHA) low-frequency recommendations (0.05 Hz).
- The Spacelabs system (0.5-30 Hz) showed more negative ST-segment displacement; the Holter recorder showed less.
- Incidence of new myocardial ischemia varied significantly: 32.1% (operating room monitor), 12.8% (standard ECG), and 8.3% (Holter recorder) intraoperatively.
Conclusions:
- Electrocardiographic system bandwidth and type significantly influence the detection of perioperative myocardial ischemia.
- Lower bandwidth filters (e.g., 0.5-30 Hz) may lead to overestimation of ischemia, while higher bandwidths (e.g., 0.1-100 Hz) may underestimate it.
- Standardization of ECG systems and bandwidths is crucial for accurate reporting and management of perioperative ischemia.
Abstract:
To determine the extent to which different electrocardiographic systems account for differences in reported incidence of perioperative myocardial ischemia, the authors simultaneously recorded in 109 patients undergoing coronary artery bypass grafting (CABG) the V5 or modified CM5 lead on five ECG systems by means of a specially constructed common V5 lead. The systems included a Spacelabs Alpha 14 Model Series 3200 ECG Cardule at bandwidths of 0.05-125 Hz and 0.5-30 Hz (a typical operating room monitor), a Marquette Electronics MAC II ECG at 0.05-40 Hz and 0.05-100 Hz (a standard ECG), and a Del Mar Holter recorder at 0.1-100 Hz. Relative ST-segment position and incidence of new ischemia compared to the preoperative ECG were determined in 109 sets of preinduction traces and 877 sets of intraoperative traces. ST-segment position on the three recording systems conforming with the American Heart Association (AHA) low-frequency response recommendations (0.05 Hz) were similar. Compared to the standard ECG, ST-segment position on the Spacelabs at 0.5-30 Hz was consistently more negative. Displacement on the Holter was consistently less negative and less positive. By the 0.1-mV displacement criterion for diagnosis of myocardial ischemia on any one ECG system, 16.5% of patients on arrival and 32.1% of patients intraoperatively suffered new myocardial ischemia. Based on the operating room monitor, arrival and intraoperative ischemia were present in 15.6 and 27.5% of patients, respectively. Ischemia at the same periods was less frequent by the standard ECG system (5.5 and 12.8%, respectively) and least frequent by the Holter recorder (4.6 and 8.3%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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