Study of U waves exemplifies important clinical role of noninvasive electrocardiography in modern cardiology. Present article highlights significance of U waves with a clinical case and also summarizes in brief the history of the same

Gupta, Mohit Dayal

MP, Girish

Mukhopadhyay, Saibal

TN, Sunil Roy

Trehan, Vijay

Yusuf, Jamal

English

PubMed

Cognitive Sciences ePrint Archive

 
www.ipej.org 63
Case Report
U  wave:  an  Important  Noninvasive  Electrocardiographic
Diagnostic Marker
Girish MP, Mohit Dayal Gupta, Saibal Mukhopadhyay, Jamal Yusuf, Sunil Roy TN, Vijay
Trehan    
Department Of Cardiology, G B Pant Hospital, New Delhi-110002, India.
Address for correspondence:Dr Mohit Dayal Gupta, Senior Resident, Academic Block, Room
no: 126, First Floor, Department of Cardiology, G B Pant Hospital, New Delhi-110002, India.
E mail: drmohitgupta@gmail.com
Abstract
            Study of U waves exemplifies important clinical role of noninvasive electrocardiography
in modern cardiology. Present article highlights significance of U waves with a clinical case and
also summarizes in brief the history of the same. 
Keywords: Electrocardiogram, U wave
            Study  of  U  waves  has  been  more  of  academic  importance  rather  than  clinical
application.  Negative  U  waves  when  present  may  be  of  immense  clinical  importance.  We
describe here one such case where U waves were not only an early noninvasive marker for acute
ischemia but they also disappeared after successful revascularization. 
            The U wave, named by Einthoven in 1903, is still a subject of debate with respect to its
origin and clinical importance1. Three hypotheses addressing the genesis of U wave that have
been put forth include late repolarization of Purkinje fibers, late repolarization of some other
portions of left ventricle, and alteration in the normal action potential shape by after-potentials2.
U waves have same polarity as T waves in normal subjects. Any alteration in the same with
respect to T wave is of importance. A 50 year old male, chronic smoker, non hypertensive and
non diabetic presented with unstable angina (Braunwald class IIIb2).Electrocardiogram showed
normal sinus rhythm with upright T waves and no ST-T changes, but prominent inverted U
waves  in  mid  precordial  leads  (Fig.1a).  Echocardiography showed  normal  LV systolic  and
diastolic function. Coronary angiogram revealed a discrete tight stenosis (90%) in the mid left
anterior descending artery (Fig. 2a). Coronary angioplasty with stenting was successfully carried
out (Fig. 2b). Immediate post procedure ECG revealed remarkable disappearance of U waves
(Fig. 1b). 
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 5(1): 63-65 (2005)
Girish MP, Mohit Dayal Gupta, Saibal Mukhopadhyay, Jamal Yusuf, Sunil Roy TN,       64
Vijay Trehan, “U wave: an Important Noninvasive Electrocardiographic Diagnostic Marker”
 
A
 
B
Figure 1:  A  Electrocardiogram showing prominent ‘U’ waves (arrows) in leads V3, V4, V5 in
patient  prior  to  intervention.  B  Post  revascularization  electrocardiogram  showing  dramatic
disappearance of U waves with similar other findings. 
 
 
A
   
B
Figure 2: A   Angiogram in Right anterior oblique cranial view showing tight stenosis in left
anterior descending artery  B  Post revascularization angiogram in Right anterior oblique cranial
view showing TIMI 3 flow in left anterior descending artery. 
            Negative U waves have low sensitivity but high specificity for heart disease and they are
recorded in approximately 1% of all electrocardiograms in general hospital3. Negative U waves
at rest, may be the earliest marker of unstable angina and evolving myocardial infarction3.  They
may also be seen at rest in cases of hypertension, variant angina, congenital long QT syndromes,
left ventricular enlargement, left anterior descending coronary artery disease and valvular heart
disease (aortic and mitral valve disease)3,4. Others however showed that negative U waves during
acute anterior wall myocardial infarction are useful in identifying patients with smaller infarction
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 5(1): 63-65 (2005)
Girish MP, Mohit Dayal Gupta, Saibal Mukhopadhyay, Jamal Yusuf, Sunil Roy TN,       65
Vijay Trehan, “U wave: an Important Noninvasive Electrocardiographic Diagnostic Marker”
and  better  collateral  circulation  but  they had  no  predictive  value  in  localizing  the  diseased
artery5. U waves on exercise may be seen in cases of significant left circumflex or right coronary
artery disease with abundant collaterals6.  
    The present case exemplifies the significance of negative U waves as the important sign of
acute  ischemia.  We believe  that  clinical  utility of  U waves  remains  underutilized  and more
clinical studies are needed to exactly define their significance in the spectrum of coronary artery
disease. 
References
1.  Einthoven  W.  Die  galvanometrische  registrierung  des  menschlichen  Electrokardiogram.
Pfluger’s Arch 1903;99:472-480.
2.  Bernardo DD, Murray A. Origin on the electrocardiogram of U-waves and abnormal U-wave
inversion. Cardiovasc Res 2002;53:202-208.
3.  Fisch  C.  The  clinical  electrocardiogram:  sensitivity  and  specificity.  ACC  Curr  J  Rev
1997;6:71-5.
4.   Gerson MC, McHenry PL. Resting U-wave inversion as a marker  of  stenosis  of the left
anterior descending coronary artery. Am J Med 1980;69:545-50.
5. Tamura A, Watanabe T, Nagase K, Mikuriya Y, Nasu M. Significance of negative U waves in
the precordial leads during anterior wall myocardial infarction. Am J Cardiol 1997;79:897-900. 
6.  Miwa K, Nakagawa K, Hirai T, Inoue H. Exercise-induced U-wave alterations as a marker of
well-developed and well-functioning collateral vessels in patients with effort angina. J Am Coll
Cardiol 2000;35:757-63. 
Indian Pacing and Electrophysiology Journal (ISSN 0972-6292), 5(1): 63-65 (2005)


Die galvanometrische registrierung des menschlichen Electrokardiogram. Pfluger’s Arch

Exercise-induced U-wave alterations as a marker of well-developed and well-functioning collateral vessels in patients with effort angina.

Origin on the electrocardiogram of U-waves and abnormal U-wave inversion.

Resting U-wave inversion as a marker of stenosis of the left anterior descending coronary artery.

Significance of negative U waves in the precordial leads during anterior wall myocardial infarction.

U wave: an Important Noninvasive Electrocardiographic Diagnostic Marker

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