- Email: [email protected]
Transient cable disconnection
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W.C.M. Rovers et al. / Journal of Electrocardiology 42 (2009) 139–144
24. Peterson SE, Mohrs OK, Horstick G, et al. Influence of contrast agent dose and image acquisition timing on the quantitative determination of nonviable myocardial tissue using delayed contrast-enhanced magnetic resonance imaging. J Cardiovasc Magn Reson 2004;6:541. 25. Wagner A, Mahrholdt H, Thomson L, et al. Effects of time, dose, and inversion time for acute myocardial infarct size measurements based on magnetic resonance imaging-delayed contrast enhancement. JACC 2006;47:2027. 26. Oshinski JN, Yang Z, Jones JR, Mata JF, French BA. Imaging time after Gd-DTPA injection is critical in using delayed enhancement to
determine infarct size accurately with magnetic resonance imaging. Circulation 2001;104:2838. 27. Hedstrom E, Arheden H, Eriksson R, Johansson L, Ahlstrom H, Bjerner T. Importance of perfusion in myocardial viability studies using delayed contrast-enhanced magnetic resonance imaging. J Magn Reson Imaging 2006;24:77. 28. Bang LE, Ripa RS, Grande P, Kastrup J, Clemmensen PM, Wagner GS. Comparison of infarct size changes with delayed contrastenhanced magnetic resonance imaging and electrocardiogram QRS scoring during the 6 months after acutely reperfused myocardial infarction. J Electrocardiol 2008;41:609.
Transient cable disconnection
The underlying rhythm in the 12-lead electrocardiogram (ECG) recorded in double standard shown above is sinus bradycardia with a single premature ventricular complex. After the first P wave, there is a truncated QRS complex seen in lead I with no ST segment or T wave; there are no visible QRS complexes in leads II or III. An apparent 2.4-second pause (shaded area) follows. Upon careful inspection of the baseline in the simultaneously recorded leads I, II, and III, the ECG signals are completely attenuated, leading to a flat line. Signal attenuation almost always represents a disconnection between the ECG lead(s) and/or the cable connections to the recording equipment. Electrocardiographic lead disconnection is common and can occur at the chest wall, the individual recording electrode being disconnected, or at the cable connection to the ECG machine. In this case, because all leads in the first recording panel display the flat line, the latter, transient cable disconnection, is more likely and indeed is what occurred in this patient. The computer interpretation, seen in the lower right-hand corner of the ECG, has even given the interpretation of “electrode: off”; the computer cannot distinguish between electrode and cable disconnections. Kurt S. Hoffmayer, PharmD, MD, and Nora Goldschlager, MD E-mail address: [email protected] doi:10.1016/j.jelectrocard.2008.11.007
W.C.M. Rovers et al. / Journal of Electrocardiology 42 (2009) 139–144
24. Peterson SE, Mohrs OK, Horstick G, et al. Influence of contrast agent dose and image acquisition timing on the quantitative determination of nonviable myocardial tissue using delayed contrast-enhanced magnetic resonance imaging. J Cardiovasc Magn Reson 2004;6:541. 25. Wagner A, Mahrholdt H, Thomson L, et al. Effects of time, dose, and inversion time for acute myocardial infarct size measurements based on magnetic resonance imaging-delayed contrast enhancement. JACC 2006;47:2027. 26. Oshinski JN, Yang Z, Jones JR, Mata JF, French BA. Imaging time after Gd-DTPA injection is critical in using delayed enhancement to
determine infarct size accurately with magnetic resonance imaging. Circulation 2001;104:2838. 27. Hedstrom E, Arheden H, Eriksson R, Johansson L, Ahlstrom H, Bjerner T. Importance of perfusion in myocardial viability studies using delayed contrast-enhanced magnetic resonance imaging. J Magn Reson Imaging 2006;24:77. 28. Bang LE, Ripa RS, Grande P, Kastrup J, Clemmensen PM, Wagner GS. Comparison of infarct size changes with delayed contrastenhanced magnetic resonance imaging and electrocardiogram QRS scoring during the 6 months after acutely reperfused myocardial infarction. J Electrocardiol 2008;41:609.
Transient cable disconnection
The underlying rhythm in the 12-lead electrocardiogram (ECG) recorded in double standard shown above is sinus bradycardia with a single premature ventricular complex. After the first P wave, there is a truncated QRS complex seen in lead I with no ST segment or T wave; there are no visible QRS complexes in leads II or III. An apparent 2.4-second pause (shaded area) follows. Upon careful inspection of the baseline in the simultaneously recorded leads I, II, and III, the ECG signals are completely attenuated, leading to a flat line. Signal attenuation almost always represents a disconnection between the ECG lead(s) and/or the cable connections to the recording equipment. Electrocardiographic lead disconnection is common and can occur at the chest wall, the individual recording electrode being disconnected, or at the cable connection to the ECG machine. In this case, because all leads in the first recording panel display the flat line, the latter, transient cable disconnection, is more likely and indeed is what occurred in this patient. The computer interpretation, seen in the lower right-hand corner of the ECG, has even given the interpretation of “electrode: off”; the computer cannot distinguish between electrode and cable disconnections. Kurt S. Hoffmayer, PharmD, MD, and Nora Goldschlager, MD E-mail address: [email protected] doi:10.1016/j.jelectrocard.2008.11.007