Baylor University Medical Center Proceedings April 2014, Volume 27, Number 2 | Page 50
Inverted P waves, QRS complexes, and T waves in lead I in a
64-year-old woman
D. Luke Glancy, MD, and Davey L. Prout Jr., MD
he combination of inverted Ps,
QRSs, and Ts in lead I (Figure 1)
suggests two possibilities: arm-lead
reversal and situs inversus with
mirror-image dextrocardia. The standard
precordial leads usually settle the issue; they
are normal in arm-lead reversal and show
diminishing QRS voltage from V1 to V6,
usually with dominant S waves, in situs
inversus. This electrocardiogram (ECG),
however, fits neither description. The precordial leads show a reverse of the usual progression. Lead V1 resembles the usual lead
V6, V2 resembles the usual V5, and so forth,
with V6 resembling the usual V1. Thus, the
precordial leads also have been reversed.
When the arm leads are reversed, lead
I is an inversion of the true lead I; lead
II is the true lead III; lead III is the true
lead II; aVR is the true aVL; aVL is the
true aVR; and aVF is unchanged. With
these caveats and the reversed sequence
of V1 to V6 in mind, this ECG is normal.
An ECG recorded 12 days later (Figure 2)
indeed is normal and resembles all of the
ECGs recorded in this patient before the
one shown in Figure 1.
The bane of the electrocardiographer
is the misinformation provided by artifacts, lead misplacement, and labeling the
ECG with the wrong name (1). Most lead
misplacement is not intentional. When
it is intentional, such as recording the
chest leads on the right side looking for
evidence of right ventricular infarction in
a patient with an acute inferior infarct,
this should be stated clearly on the tracing.
T
1.
124
Figure 1. ECG in a 64-year-old woman.
Figure 2. ECG in the same woman 12 days later.
Surawicz B, Knilans TK. Misplacement of leads and electrocardiographic
artifacts. In Surawicz B, Knilans TK, eds. Chou’s Electrocardiography in
Clinical Practice: Adult and Pediatric, 5th ed. Philadelphia: WB Saunders,
2001:569–582.
From the Sections of Cardiology, Departments of Medicine, Louisiana State University
Health Sciences Center and the Interim LSU Hospital, New Orleans, Louisiana.
Corresponding author: D. Luke Glancy, MD, 7300 Lakeshore Drive, #30, New
Orleans, LA 70124 (e-mail: [email protected]).
Proc (Bayl Univ Med Cent) 2014;27(2):124