CME INDIA Case Presentation by Prof. Dr. M. Chenniappan, MD, DM, FACC, FACP, FRCP. Consultant Cardiologist, Ramakrishna Nursing Home, National Professor of IMA – CGP. Director of Medical Education, Apollo Speciality Hospital, Thiruchirappalli (Tamil Nadu, India).

CME INDIA Case Study

“Confusion of Colours”

ECG NO 1:

Routine ECG of 68 Years-Old Male

What are the ECG findings?

• This ECG shows sinus rhythm with left anterior fascicular block (LAFB) and PR interval in the upper limit. There is sudden appearance of Tall R wave in V3 (>V4) and sudden disappearance of R wave in V5.
• In V5 and V6 QRS complex is looking completely different. The unexpected appearance of R wave in one lead and sudden disappearance of R wave in another lead are suggestive of chest electrode malposition.
• Here electrode of V5 is placed in V3 position and electrode for V3 is placed in V5 position resulting in this unusual appearance and disappearance of R wave. This type of ECG change cannot be explained by electrocardiographic terms because the configuration of QRS in V5 and V6 is most often similar in normal ECG.

Why is this clue?

The ECG technicians most often do the error of misplacing electrodes either in limb leads or in the chest leads. To avoid this error chest electrodes are given colours. So that the technician remembers the colours for the specific electrode and place it in a correct place.

• These colours can be remembered easily by the following method. Electrodes V1 – V3 remember traffic signals (Red, Yellow, Green) Electrodes V4-V6 remember the pneumonic “BOP” (Brown, Orange, Purple).
• In this simple way technicians can identify the chest electrodes and place it in the correct place without looking at the letter in the electrode like V1, V2, etc. In this ECG, orange is placed in Green position and Green is placed in orange position resulting in abnormal QRS complexes in V3 and V5. That is why the clue of “Confusion of Colours” is given.

Learning Points

• Correct ECG recording is an essential prerequisite for the right interpretation of Electrocardiogram. So, the ECG technician/paramedics who record the ECG should be taught how to connect the electrodes in the limbs as well as how to place chest electrodes in the correct positions.
• Most often technicians make error because they do not look at the name of the letters inscribed on that electrode and in a hurry, they misplace the chest electrodes. If they are taught the positioning of the chest electrodes as well as the limb electrodes through the colours it is easy for them to place the electrodes in a correct position.
• Some of this wrongly recorded ECGs may give a wrong diagnosis like dextrocardia, Myocardial Infarction, Ventricular enlargement etc. and the patient may get inappropriate and incorrect treatment. So, educating the technicians in a simple way through colour coding of electrodes is an efficient method of making sure that the ECG is recorded properly.

“Don’t Ignore Chest in Chest Leads”

ECG No:2

This is the Routine ECG of the 70-Year-Old Man

What are the ECG findings?

• The ECG shows non progression of R wave in V1-V4. Non progression of R wave or poor prognosis of R wave in chest leads is a vague term. It is not a diagnosis but a pattern. In normal individuals R increase in voltage from V1-V4.
• “Depace” criteria to diagnose poor R wave progression is that in 1 mv standardization the R in V3 in equal or less than 3 mm it is considered poor R wave progression. The other criteria are that R in V1 is less than V2, R in V2 is less than R in V3 and R in V3 is less than V4. With this criterion this ECG shows poor prognosis of R wave.
• The second step is to identify what has caused poor R wave progression. Apart from Anterior MI, there are many causes of poor R wave prognosis. COPD, Obesity, Dextrocardia, Pregnancy, LBBB, Improper placement of chest electrodes are some of the most important causes.

What is the clue?

• In this patient the non-progression is due to chest wall abnormality of pectus excavatum. If you see the ECG alone without looking at the chest of the patient, you will miss the diagnosis, that’s why this clue is given.

Learning Points

• Now let us undergo the ECG signs produced by pectus excavatum which is posterior depression of sternum and costal cartilages.
• This results in compression and leftward displacement of heart. The common ECG changes are nonspecific ST T changes and poor prognosis of R in V1-V4 which with mimic CAD. In addition to this many ECG changes such as incomplete blockade of His, VPDs and MVP in more than 90% of cases may be present.
• When poor R progression is present, record ECGs one space above or below depending upon the condition to rule out organic causes. In obesity, ascites and pregnancy it is one space above and in tall lean individuals and emphysema it is one space below. If R wave progresses in repositioned leads, it is unlikely due to organic causes such as AWMI.

“Obvious is Obvious, Look for Unobvious”

ECG NO 3:

This is the ECG of 50-Year Diabetic with Intermittent Chest Pain

Obvious

• The presence of Right Bundle Branch Block (RBBB), left anterior fascicular block and anterolateral and high lateral pathological Q waves are obvious indicating Antero and high lateral MI.

Unobvious

• Unobvious is associated Posterior Wall Myocardial Infarction (PWMI). Most often it is difficult to diagnose PWMI in the presence of RBBB.
• One should concentrate on initial R wave in RBBB. In uncomplicated RBBB, in V1 this initial r is due to septal activation occurring from Left to Right and it is narrow and small – but in the presence of RBBB, the initial R wave becomes tall and broad in V1.
• In addition, there may be homophasic ST T changes in V1 where ST T are in the same direction as QRS. So, in this ECG, in addition to Anterior Injury and ischemia, patient has old PWMI indicated by Tall and Broad initial R in V1. (Fig.1)

Learning Points

• It is always a good practice to look for PWMI in inferior MI whether it is in acute phase or chronic phase in the form of reciprocal ST depression or Tall R in VI respectively.
• Association of PWMI in addition to IWMI indicates more myocardial involvement and more extensive disease. This ECG illustrates how to diagnose PWMI in the presence of RBBB which masks chronic PWMI.

“Unexpected Absence and Presence”

ECG NO 4:

72 Y Palpitations; Known COPD

What are the findings?

• This is the ECG of 72 years old man with COPD which shows normal sinus rhythm with frequent VPDs of RVOT origin without compensatory pause- interpolated VPDs.
• The basic sinus rate is around 60/minute – Basic Bradycardia. So, the PR interval following the VPD is prolonged due to concealed retrograde conduction of VPD.
• The change in the P wave configuration of the sinus beat following VPD is due to P wave falling on T wave. In addition, there is frequent atrial premature beats probably arising from the Right atrium with normal intra ventricular conduction followed by full compensated pause. (The P-P interval which includes the Atrial Premature Beats is exactly twice of the basic sinus cycle).
• The atrial and ventricular premature beats are alternating with sinus beats. Basic sinus beats do not show significant abnormality. There is no L 1 sign of COPD.

Clues

The ECG shows following interesting findings:

• RVOT VPDs.
• Interpolated.
• Concealed retrograde conduction.
• VPD, APD alternating with sinus beat.
• Right Atrial premature depolarisation.
• APD is having full compensatory pause.
• No significant changes in the Basic ECG.
• RVOT VPDs.
• Interpolated.
• Concealed retrograde conduction.
• VPD, APD alternating with sinus beat.
• Right Atrial premature depolarisation.
• APD is having full compensatory pause.
• No significant changes in the Basic ECG.

• Unexpected absence – Absence of complete compensatory pause in VPD.
• Unexpected presence – Presence of complete compensatory pause in APD (usually APD has incomplete compensatory pause). That is why the clue of “Unexpected absence and presence” is given.

Leaning Points

• APDs and VPDs indicate increased irritability of atrium and ventricles. Interpolated VPDs are expected with basic bradycardia. Because of basic sinus bradycardia and COPD betablockers cannot be given as anti-arrhythmic drugs. Because of the VPD configuration and RVOT origin it is likely to be benign.
• APDs and VPDs are expected in COPD because of the hypoxia and treatment with sympathomimetic agents. As this patient may be using sympathomimetic agents/inhalers, hypokalemia as the cause of Premature beats must be excluded. After stopping stimulants like coffee, tobacco, alcohol, and sympathomimetic agents, if still these arrhythmias are present, Holter may be done to decide about further management.

(This series is brought in collaboration with USV)

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