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Editorial Views  |   February 2002
Multilead Precordial ST-segment Monitoring: “The Next Generation?”
Author Notes
  • Professor of Clinical Anesthesia, Department of Anesthesia and Perioperative Care, San Francisco Veterans Affairs Medical Center/University of California, San Francisco, San Francisco, California.
Article Information
Editorial Views
Editorial Views   |   February 2002
Multilead Precordial ST-segment Monitoring: “The Next Generation?”
Anesthesiology 2 2002, Vol.96, 259-261. doi:
Anesthesiology 2 2002, Vol.96, 259-261. doi:
A QUARTER century has passed since the first reports describing use of precordial lead V5to monitor for intraoperative ischemia were published, and over a decade has passed since we documented its sensitivity (75%) using continuous 12-lead monitoring in 100 patients. 1,2 Since then, V5has become “a clinical routine.” In this issue, Landesberg et al.  present “the next generation,” monitoring a larger cohort (185 patients) undergoing higher-risk surgery (all vascular surgery), for a longer period of time (48–72 h). 3 Their results extend our knowledge and add controversy, given their finding that leads V3(75%) and V4(83%) are either equal or more sensitive than V5(75%). They recommend use of V4over V5since its ST-segment is most commonly isoelectric on the baseline electrocardiogram, extrapolating that this makes it more likely to reflect ischemic changes. They also recommend the use of two precordial leads to approach 95% sensitivity to detect ischemia or infarction.
Should this study alter our current clinical practice? Should we “move to the right” in favor of V3or V4and abandon V5? Should we encourage bipartisanship by monitoring two precordial leads (requiring equipment modification)? Or should we take the Libertarian approach by encouraging simplicity in monitoring? I would argue that with the clinical data accumulated over the past 10–15 yr. documenting associations of perioperative tachycardia and ST-segment depression to adverse outcome and beneficial effects of β-blockade, that sophisticated monitoring is considerably less important than adequate prophylaxis and therapy. 4,5 However, since it is known that β-blockade cannot ensure suppression of ischemia nor prevention of infarction in all patients, evaluation of the current status of multi-lead monitoring remains worthy of serious consideration. 6 
Reference cardiology texts state that subendocardial ischemia induced by demand-related stress is manifested by ST-segment depression in lead V5and does not localize the anatomic site of coronary obstruction. 7 Yet even Mason and Likar, the first to use the now universal torso-mounted axial leads during exercise treadmill testing (ETT), reported that V6, not V5, was the most sensitive lead! 8 Subsequent investigators have reported varying sensitivity, particularly between V4, V5, and V69–13 (table 1).
Table 1. Studies of 12-lead Sensitivity
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Table 1. Studies of 12-lead Sensitivity
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How can we reconcile these differences? Examination of these studies reveals differences in ST-segment criteria, (including magnitude and timing after the J-point, varying even with the number of leads involved); the time period considered (during exercise, during recovery, perioperatively, etc.); temporal duration (with Landes- berg et al.  requiring prolonged duration > 10 min.) 3; mode of analysis (visual vs.  computerized); incorporation of other physiologic parameters; and less frequently, but of considerable theoretical interest, normalization based on the height of accompanying R-wave. 14 With all of these factors, any simple explanation is likely impossible. Given the common adage that the ST-segment vector during subendocardial ischemia is directed towards the apex of the ventricle (which V5is said to be closest to), it is possible that anthropomorphic factors influencing the position of the heart in the chest such as gender, body habitus, and chest diameter may be important. However, this has not been studied. Complex physiologic approaches using noninvasive body surface mapping have been used, and more recently invasive endo- and epicardial potentials with three-dimensional computer modeling has provided an alternative approach. 15 
Why is there not greater interest in the cardiology community to nail down the precise sensitivities? Possible explanations include (1) nearly all stress tests in this country use computerized 12-lead systems, (2) there is strong evidence that a positive response in multiple leads (along with greater magnitude of depression and presence of a downsloping ST-segment) is related to a larger area of myocardium at risk 16,17 and (3) despite calls for cost containment, thallium imaging, even after a positive endotracheal tube is very common (as is cardiac catheterization). In clinical practice, the whole of the 12-lead electrocardiogram is clearly greater than the sum of its parts.
Another factor is the growing interest in continuous 12-lead monitoring for patients with acute coronary syndromes (ACS). With transmural ischemia, lead sensitivity is closely associated with the site of coronary occlusion (whether transient or permanent) with leads V2and V3most sensitive for left anterior descending occlusion, and lead III most sensitive for the right coronary artery. In this setting, ST-segment elevation is a nearly universal finding. Circumflex occlusion results in a variable response with primary elevation in posterior precordial leads (i.e.  , V7, V8, etc.) or reciprocal ST-depression in other precordial or axial leads. 1 A recent multidisciplinary working group recommends leads III, V3, and V5as the most sensitive combination for patients with ACS. 18 
Krucoff et al.  were the first to make a serious argument for the value of continuous 12-lead electrocardiogram monitoring in ACS patients with the concept of the “12-lead fingerprint,” a unique pattern of leads and ST segment magnitude sensitive to detecting reocclusion after percutaneous transluminal coronary angioplasty (PTCA). 19 This approach has been used in major studies of thrombolysis. Many intensive care unit bedside monitors (and telemetry monitors) are now “12-lead ECG capable” with a precordial lead cable and continuous ST segment trending of all 12 leads. Recent American and European ACS Guidelines now acknowledge the utility of this approach but make no firm recommendations for it. 20,21 However, this approach includes a high rate of false-positive responses (40%) because of changes in QRS amplitude or vector with positional changes, arrhythmia/pacing artifact and heart-rate–related changes in ST-segment contour. 22 In the perioperative setting, the array of catheters, monitors, and drains and the need to mobilize patients quickly are major logistical obstacles. Artifact issues and the economically unfavorable task of investigating episodes are formidable factors.
Aside from the monitoring issues raised by this study, there is important information on perioperative ischemia. As noted in the parent publication, duration of ischemia is a significant predictor of peak cTn-I level, ischemic events associated with infarction are preceded by increased heart rate (32 beats/min). People with diabetes and patients with left ventricular hypertrophy (LVH) are at highest risk. 23 Diabetics are already known to be at high risk for adverse outcome. 24 Less is known about LVH since many studies excluded these patients because of concerns that the increased QRS voltage may exaggerate the ST-segment response. 14 We previously noted that LVH was the strongest preoperative factor multivariately associated with postoperative ischemia. 25 Left ventricular hypertrophy is associated with accelerated atherosclerosis, subendocardial ischemia, and adverse long-term outcome. 26 But its association with plaque disruption  , likely the necessary ingredient for overt morbidity, is suggested by a recent study comparing angiographic results over a 6 months interval. 27 The strongest adverse multivariate associations were LV mass and elevated heart rate (> 80 bpm), while the strongest protective association was with chronic β-blocker use.
Integrating the monitoring and clinical data, it seems reasonable that sophisticated monitoring may be of value to people with diabetes and those with LVH. A targeted study in these cohorts of the value of therapeutic intervention guided by multi-lead monitoring (in the setting of concurrent β-blockade) would be most helpful. My clinical observations are that precordial lead placements by physicians and nurses at all levels of training remain imprecise (and are unavoidably affected by surgical factors). Thus, I recommend that clinicians use a “true” V4or V5along with an inferior axial lead, control heart rate and pain, and use β-blockers as tolerated for all patients at risk.
References
London MJ, Kaplan JA: Advances in electrocardiographic monitoring, Cardiac Anesthesia, 4th edition. Edited by Kaplan JA, Reich DL, Konstadt SN. Philadelphia, WB Saunders, 1999, pp 359–400
London MJ, Hollenberg M, Wong MG, Levenson L, Tubau JF, Browner W, Mangano DT: Intraoperative myocardial ischemia: Localization by continuous 12-lead electrocardiography. A nesthesiology 1988; 69: 232–241London, MJ Hollenberg, M Wong, MG Levenson, L Tubau, JF Browner, W Mangano, DT
Landesberg G, Mosseri M, Wolf Y, Veselov Y, Weissman C: Perioperative myocardial ischemia and infarction: Identification by continuous 12-lead with on-line ST-segment monitoring. A nesthesiology 2002;in press 
Mangano DT, Browner WS, Hollenberg M, London MJ, Tubau JF, Tateo IM: Association of perioperative myocardial ischemia with cardiac morbidity and mortality in men undergoing noncardiac surgery. N Engl J Med 1990; 323: 1781–8Mangano, DT Browner, WS Hollenberg, M London, MJ Tubau, JF Tateo, IM
Landesberg G, Luria MH, Cotev S, Eidelman LA, Anner H, Mosseri M, Schechter D, Assaf J, Erel J, Berlatzky Y: Importance of long-duration postoperative ST-segment depression in cardiac morbidity after vascular surgery. Lancet 1993; 341: 715–9Landesberg, G Luria, MH Cotev, S Eidelman, LA Anner, H Mosseri, M Schechter, D Assaf, J Erel, J Berlatzky, Y
Boersma E, Poldermans D, Bax JJ, Steyerberg EW, Thomson IR, Banga JD, van De Ven LL, van Urk H, Roelandt JR: Predictors of cardiac events after major vascular surgery: Role of clinical characteristics, dobutamine echocardiography, and beta-blocker therapy. JAMA 2001; 285: 1865–73Boersma, E Poldermans, D Bax, JJ Steyerberg, EW Thomson, IR Banga, JD van De Ven, LL van Urk, H Roelandt, JR
Froelicher VF: ECG exercise testing, Hurst's The Heart, 10th edition. Edited by Fuster V, Alexander RW, O'Rourke RA. New York, McGraw-Hill, 2001, pp 461–78
Mason RE, Likar I, Biern RO, Ross RS: Multiple-lead exercise electrocardiography: Experience in 107 normal subject and 67 patients with angina pectoris, and comparison with coronary cinearteriography in 84 patients. Circulation 1967; 36: 517–25Mason, RE Likar, I Biern, RO Ross, RS
Weyne AE, De Buyzere ML, Bauwens FR, Clement DL: Assessment of myocardial ischemia by 12-lead electrocardiography and Frank vector system during coronary angioplasty: Value of a new orthogonal lead system for quantitative ST segment monitoring. J Am Coll Cardiol 1991; 18: 1704–10Weyne, AE De Buyzere, ML Bauwens, FR Clement, DL
Jensen SM, Johansson G, Osterman G, Reiz S, Naslund U: On-line computerized vectorcardiography monitoring of myocardial ischemia during coronary angioplasty: Comparison with 12-lead electrocardiography. Coron Artery Dis 1994; 5: 507–14Jensen, SM Johansson, G Osterman, G Reiz, S Naslund, U
Gannedahl PE, Edner M, Ljungqvist OH: Computerized vectorcardiography for improved perioperative cardiac monitoring in vascular surgery. J Am Coll Surg 1996; 182: 530–6Gannedahl, PE Edner, M Ljungqvist, OH
Klootwijk P, Meij S, von Es GA, Muller EJ, Umans VA, Lenderink T, Simoons ML: Comparison of usefulness of computer assisted continuous 48-h 3-lead with 12-lead ECG ischaemia monitoring for detection and quantitation of ischaemia in patients with unstable angina. Eur Heart J 1997; 18: 931–40Klootwijk, P Meij, S von Es, GA Muller, EJ Umans, VA Lenderink, T Simoons, ML
Viik J, Lehtinen R, Turjanmaa V, Niemela K, Malmivuo J: The effect of lead selection on traditional and heart rate-adjusted ST segment analysis in the detection of coronary artery disease during exercise testing. Am Heart J 1997; 134: 488–94Viik, J Lehtinen, R Turjanmaa, V Niemela, K Malmivuo, J
Gibbons RJ, Balady GJ, Beasley JW, Bricker JT, Duvernoy WF, Froelicher VF, Mark DB, Marwick TH, McCallister BD, Thompson PD, Jr, Winters WL, Yanowitz FG, Ritchie JL, Cheitlin MD, Eagle KA, Gardner TJ, Garson A, Jr, Lewis RP, O'Rourke RA, Ryan TJ: ACC/AHA Guidelines for Exercise Testing: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Exercise Testing). J Am Coll Cardiol 1997; 30: 260–311Gibbons, RJ Balady, GJ Beasley, JW Bricker, JT Duvernoy, WF Froelicher, VF Mark, DB Marwick, TH McCallister, BD Thompson, PD Winters, WL Yanowitz, FG Ritchie, JL Cheitlin, MD Eagle, KA Gardner, TJ Garson, A Lewis, RP O'Rourke, RA Ryan, TJ
Li D, Li CY, Yong AC, Kilpatrick D: Source of electrocardiographic ST changes in subendocardial ischemia. Circ Res 1998; 82: 957–70Li, D Li, CY Yong, AC Kilpatrick, D
Watanabe T, Harumi K, Akutsu Y, Yamanaka H, Michihata T, Okazaki O, Katagiri T: Correlation between exercise-induced ischemic ST-segment depression and myocardial blood flow quantified by positron emission tomography. Am Heart J 1998; 136: 533–42Watanabe, T Harumi, K Akutsu, Y Yamanaka, H Michihata, T Okazaki, O Katagiri, T
Tavel ME, Shaar C: Relation between the electrocardiographic stress test and degree and location of myocardial ischemia. Am J Cardiol 1999; 84: 119–24Tavel, ME Shaar, C
Drew BJ, Krucoff MW: Multilead ST-segment monitoring in patients with acute coronary syndromes: A consensus statement for healthcare professionals. ST-Segment Monitoring Practice Guideline International Working Group. Am J Crit Care 1999; 8: 372–86Drew, BJ Krucoff, MW
Krucoff MW, Parente AR, Bottner RK, Renzi RH, Stark KS, Shugoll RA, Ahmed SW, DeMichele J, Stroming SL, Green CE, Rackley CE, Kent KM: Stability of multilead ST-segment “fingerprints” over time after percutaneous transluminal coronary angioplasty and its usefulness in detecting reocclusion. Am J Cardiol 1988; 61: 1232–7Krucoff, MW Parente, AR Bottner, RK Renzi, RH Stark, KS Shugoll, RA Ahmed, SW DeMichele, J Stroming, SL Green, CE Rackley, CE Kent, KM
Bertrand ME, Simoons ML, Fox KA, Wallentin LC, Hamm CW, McFadden E, de Feyter PJ, Specchia G, Ruzyllo W: Management of acute coronary syndromes: Acute coronary syndromes without persistent ST segment elevation; recommendations of the Task Force of the European Society of Cardiology. Eur Heart J 2000; 21: 1406–32Bertrand, ME Simoons, ML Fox, KA Wallentin, LC Hamm, CW McFadden, E de Feyter, PJ Specchia, G Ruzyllo, W
Braunwald E, Antman EM, Beasley JW, Califf RM, Cheitlin MD, Hochman JS, Jones RH, Kereiakes D, Kupersmith J, Levin TN, Pepine CJ, Schaeffer JW, Smith EE III, Steward DE, Theroux P, Gibbons RJ, Alpert JS, Eagle KA, Faxon DP, Fuster V, Gardner TJ, Gregoratos G, Russell RO, Smith SC Jr: ACC/AHA guidelines for the management of patients with unstable angina and non-ST-segment elevation myocardial infarction: Executive summary and recommendations. A report of the American College of Cardiology/American Heart Association task force on practice guidelines (committee on the management of patients with unstable angina). Circulation 2000; 102: 1193–209Braunwald, E Antman, EM Beasley, JW Califf, RM Cheitlin, MD Hochman, JS Jones, RH Kereiakes, D Kupersmith, J Levin, TN Pepine, CJ Schaeffer, JW Smith, EE Steward, DE Theroux, P Gibbons, RJ Alpert, JS Eagle, KA Faxon, DP Fuster, V Gardner, TJ Gregoratos, G Russell, RO Smith, SC
Drew BJ, Wung SF, Adams MG, Pelter MM: Bedside diagnosis of myocardial ischemia with ST-segment monitoring technology: measurement issues for real-time clinical decision-making and trial designs. J Electrocardiol 1998; 30: 157–65Drew, BJ Wung, SF Adams, MG Pelter, MM
Landesberg G, Mosseri M, Zahger D, Wolf Y, Perouansky M, Anner H, Berlatzky Y, Weissman C: Myocardial infarction following vascular surgery: the role of prolonged, stress-induced, ST-depression-type ischemia. J Am Coll Cardiol 2001; 37: 1839–45Landesberg, G Mosseri, M Zahger, D Wolf, Y Perouansky, M Anner, H Berlatzky, Y Weissman, C
Mangano DT, Layug EL, Wallace A, Tateo I: Effect of atenolol on mortality and cardiovascular morbidity after noncardiac surgery. N Engl J Med 1996; 335: 1713–20Mangano, DT Layug, EL Wallace, A Tateo, I
Hollenberg M, Mangano DT, Browner WS, London MJ, Tubau JF, Tateo IM: Predictors of postoperative myocardial ischemia in patients undergoing noncardiac surgery. JAMA 1992; 268: 205–9Hollenberg, M Mangano, DT Browner, WS London, MJ Tubau, JF Tateo, IM
Benjamin EJ, Levy D: Why is left ventricular hypertrophy so predictive of morbidity and mortality? Am J Med Sci 1999; 317: 168–75Benjamin, EJ Levy, D
Heidland UE, Strauer BE: Left ventricular muscle mass and elevated heart rate are associated with coronary plaque disruption. Circulation 2001; 104: 1477–82Heidland, UE Strauer, BE
Table 1. Studies of 12-lead Sensitivity
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Table 1. Studies of 12-lead Sensitivity
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