[Long-term electrocardiography. Detection of low-grade myocardial infarction: sensitivity of 9 bipolar leads].
The sensitivity of ambulatory electrocardiography (Holter ECG) for detecting ischaemia is relatively low. A case report of an inferior infarction missed by three-lead Holter monitoring that included a modified lead aVF especially places its sensitivity for detecting inferior ischaemia and infarction in question. Therefore, the present study evaluated the sensitivity of nine bipolar Holter leads for detecting isolated inferior Q-wave infarctions, and compared the sensitivity of the modified leads II, III, and aVF of the Holter ECG with the sensitivity of the "corresponding" leads of the standard ECG.


METHODS
Sixteen patients, each of whom had a pathological Q-wave (> 0.04 s and > 0.1 mV) in at least two of the three standard ECG leads II, III, and aVF but in none of the other standard leads, were studied for the presence of a pathological Q-wave on the modified Holter leads II, III, aVF, CM2, CM5, CR4, Frank Z, Nehb D, and inverse Nehb J.


RESULTS
Of the nine Holter leads, modified lead III provided the highest sensitivity for detecting inferior Q-wave infarctions, followed by lead Frank Z; leads CR 4 and inverse Nehb J were only slightly less sensitive. In contrast, modified leads II and aVF were significantly less sensitive than modified lead III. Modified bipolar lead aVF of the Holter ECG was significantly less sensitive than the "corresponding" lead aVF of the standard ECG, whereas modified leads II and III provided similar sensitivities for detecting inferior Q-wave infarctions as the "corresponding" leads of the standard ECG.


CONCLUSIONS
The significantly lower sensitivity of modified lead aVF for detecting inferior Q-wave infarctions compared with standard lead aVF shows that the sensitivity of a Holter ECG lead cannot be deduced from that of the "corresponding" standard ECG lead. Moreover, the significantly higher sensitivity of modified lead III compared with modified leads II and aVF shows that lead selection is important for Holter monitoring.
Seeberger
M D
MD
Department Anästhesie, Universität Basel, Kantonsspital Basel.
Skarvan
K
K
Kindler
C H
CH
Friedli
D
D
D000368:Aged; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000503:physiopathology