Approach to a patient with U wave in ECG

Case-1: a 45 years old gentleman presented with this ECG during his follow up in the chamber. He is hypertensive and getting beta-blocker to control of his hypertension
Case-2: A 25 years old gentleman presented with several episodes of diarrhea and vomiting for last 12 hours. He had the following ECG. His K+ level was 2.8 meq/L. .
The U wave is a small (0.5 mm) deflection immediately following the T wave
U wave is usually in the same direction as the T wave.
U wave is best seen in leads V2 and V3.
 Many of the conditions causing prominent U waves will also cause a long QT.

1. Fundamentals of ECG
U wave in ECG
Dr. Md.ToufiqurRahman
MBBS, FCPS, MD, FACC, FESC, FRCP, FSCAI,
FCCP,FAPSC, FAPSIC, FAHA,FACP
Professor & head of Cardiology
CMMC, Manikganj
Ex professor of cardiology,
NICVD, Dhaka

2. [email protected] DrMdToufiqurRahman
Fundamentals of ECG U wave

3. Fundamentals of ECG U wave
Case-1:a45yearsoldgentlemanpresentedwiththisECG
duringhisfollowupinthechamber.Heishypertensiveand
gettingbeta-blockertocontrolofhishypertension.
Figure: ECG showing U wave in a patient of
bradycardia

4. Fundamentals of ECG U wave
Case-2:A25yearsoldgentlemanpresentedwith
severalepisodesofdiarrheaandvomitingforlast12
hours.HehadthefollowingECG.HisK+levelwas2.8
meq/L..
Figure: Prominent U waves in a patient with
hypokalaemia

5. Fundamentals of ECG U wave
Case-3:A54yearsoldgentlemanpresentedwith
uncontrolledHypertension.HisBPwas160/100mmHg.He
hadthefollowingECG.
Figure: ECG showing u wave in a patient with Left
Ventricular hypertrophy

6. Fundamentals of ECG U wave
Case 5: A 53 years old lady presented with shortness of breath for last
6 months. She is a diagnosed case of dilated cardiomyopathy with
severe LV systolic dysfunction. On echocardiography , LVIDdwas 65
mm and LA was 48 mm with mitral regurgitation. She was taking
digoxin along other drugs.
Figure: ECG showing U wave in a patient with getting digoxin

7. Fundamentals of ECG U wave
Case 6: A 61 years old gentleman diabetic, hypertensive and
smoker presented with chest discomfort with excessive
sweating and vomiting for last 1 hour.
He had the following ECG.
Figure: Inverted U waves in a patient with unstable angina.

8. Fundamentals of ECG U wave
Case 7: A 33 years old gentleman smoker presented with
severe chest pain with sweating at early morning that
waked up him from sleeping . He was a occasional cocaine
user. His chest pain was being relieved by taking sublingual
nitrates. He had the following ECG during his chest pain
Inverted U waves in a patient with Prinzmetalangina.

9. Fundamentals of ECG U wave
Case 8: A 65 years old lady presented with sudden severe
chest discomfort with excessive sweating for last 4 hours.
She was diabetic and dyslipidemic. Troponin I level was
raised. She had the following ECG.
Subtle Inverted U waves in the lateral leads (I, V5
and V6) a patient in with NSTEMI.

10. Fundamentals of ECG U wave
The U wave is a small (0.5 mm)
deflection immediately following the T
wave
U wave is usually in the same direction
as the T wave.
U wave is best seen in leads V2 and V3.
Many of the conditions causing
prominent U waves will also cause a
long QT.
Characteristics of U wave

11. Fundamentals of ECG U wave
The U wave normally goes in the same direction
as the T wave.
U -wave size is inversely proportional to heart
rate: the U wave grows bigger as the heart rate
slows down
U waves generally become visiblewhen the heart
rate falls below 65 bpm
The voltage of the U wave is normally < 25% of
the T-wave voltage: disproportionally large U
waves are abnormal
Maximum normal amplitude of the U wave is 1-2 mm
Features of Normal U waves

12. Fundamentals of ECG U wave
The source of the U wave is unknown.
Three common theories regarding its
origin are:
Delayed repolarisationof Purkinje fibres
Prolonged repolarisationof mid-
myocardial “M-cells”
After-potentials resulting from
mechanical forces in the ventricular
wall
Source of the U wave

13. Fundamentals of ECG U wave
Prominent U waves
U waves are described as prominent if they are
>1-2mm or 25% of the height of the T wave.
Causes of prominent U waves
Prominent U wavesmost commonlyfound with:
oBradycardia
oSevere hypokalaemia.
Prominent U wavesmaybe present with:
Hypocalcaemia
Hypomagnesaemia
Hypothermia
Raised intracranial pressure
Left ventricular hypertrophy
Hypertrophic cardiomyopathy
Drugsassociated with prominent U waves:
Digoxin
Phenothiazines(thioridazine)
Class Iaantiarrhythmics(quinidine, procainamide)
Class III antiarrhythmics(sotalol, amiodarone)

14. Fundamentals of ECG U wave
U-wave inversion is abnormal (in leads with upright T
waves)
A negative U wave is highly specific for the presence of
heart disease
Common causes of inverted U waves
Coronary artery disease
Hypertension
Valvularheart disease
Congenital heart disease
Cardiomyopathy
Hyperthyroidism
Inverted U waves