Showing posts with label ECG. Show all posts
Showing posts with label ECG. Show all posts

ECG changes in Acute severe Asthma

Pulmonary Medicine Blog By Dr Deepu

Reversible ECG changes in Acute severe Asthma

Dear Friends I got a call from the emergency department to treat a patient who was gasping for air, the intern at the ER department informed me that the patient had RAD, RBBB and P pulmonale, After examining the patient and taking proper history from the attendants we came to know that the patient is an asthmatic and this was an acute asthmatic attack. Then the intern was baffled by the ECG changes, he thought the event to be a acute cardiac event, I then explained him the ECG changes which are seen in acute asthma. I thought to share the same with you
Here are the ECG changes in Acute Severe Asthma
1.     Sinus tachycardia
2.      Right axis deviation
3.      P pulmonale 
4.      Precordial leads -  voltage of the "p" wave is reduced
5.      Poor progression of the R wave in the precordial leads and marked persistence of the S wave in the left precordial leads
6.      Right bundle branch block
7.      Ventricular premature complexes
8.     Atrial enlargement
9.     Transient ST-segment depression or elevation     in inferior leads ; T-wave abnormalities
10.                        Ventricular repolarization shows a lowered J point with an upward oblique ST segment in the peripheral leads
The mechanism of these electrocardiographic changes appears to depend on the vertical position of the heart caused by over expansion of the lungs and pulmonary arterial hypertension
What are the causes of ECG changes???
1.     Adrenergic stimulation
2.     Hyperventilation
3.     Hyperinflation
4.     Primary or secondary coronary insufficiency
5.     Severity of ECG signs correlates with the degree of airway obstruction.

So, Various ECG changes can occur in acute severe asthma which are nonspecific and these may mimic an acute cardiac event and can cause diagnostic dilemma, most of these changes are reversible usually within 10 days of treatment


Here are  basics of how ECG is done with leads placement and the recording of various waves in an ECG  recording.

1.Lead placement 

2. Electrical activity of the heart
3. various waves in ECG

4. Changes in ECG with evolution of MI

Hope the images gave a GOOD OVERVIEW OF ECG. please ask questions in the comment box below.


The standard 12-lead ECG does not directly examine the right ventricle and does a relatively poor job at examining the posterior basal and lateral wall of the left ventricle. 

As a result we often miss acute STEMI in the distribution of the circumflex. ST-depression that is maximal in leads V1-V3 is sometimes erroneously attributed to "anterior ischemia" (a misnomer) and leads I and aVL can be "electrocardiographically silent" (less than 1 mm ST-elevation) which makes reciprocal changes in the inferior leads very important!

The use of additional leads like V4R  and posterior leads V7, V8, and V9 may improve sensitivity for right ventricular and posterior infarction. But be careful! Posterior leads V7, V8, and V9 can be negative and the LCX can still be occluded!

So next time when you are in confusion go for that extra leads!!!!


Today while browsing on the internet I came across this simplified and funny picture about the AV block, take a look at this

and for the older Topics, you can search through the index or topics or through the blog list at the end of this page


Here is an image showing the various leads in ECG, The Facing leads and the reciprocal ones. Keep one in your clinic, turns out to be very handy

How To determine the Mean Electrical Axis in ECG?????? Simple isn't it!!!

Electrical axis...

  • Mean direction of the QRS complex in the frontal plane towards which the QRS complex is predominately
  • Since by definition it is calculated in frontal plane only, therefore MEAN ELECTRICAL AXIS is calculated
 only from the frontal or Limb leads.
Mean QRS Axis Calculation
  • the mean QRS axis is oriented at right angles (90°) to any lead showing a bi-phasic complex
  • the mean QRS axis points midway between any two leads that show tall R waves of equal height
This program demonstrates changes in the frontal surface leads with shifts in the cardiac axis .

Calculation of frontal plane axis : If the QRS complex is positive in leads I and II, it falls between -30 and 90°
 and is normal, as indicated by the yellow area. If the QRS complex is negative in I and positive in aVF, 
there is right axis deviation. If the QRS complex is positive in I and negative in II, there is left axis deviation.
 If the QRS complex is negative in I and aVF, there is extreme axis deviation.

A Systematic Approach to Electrocardiogram (EKG) Interpretation by Using 2 Mnemonics!!! Sounds Good!!!

Step 1: Evaluate all elements of the EKG systematically: A RARE PQRST.
Step 2: Differential diagnosis. Look for diseases that may have caused the abnormalities noted in step 1: DR III EEE !
This systematic approach to reading electrocardiograms (ECGs or EKGs) works every time, just like a machine. By using it, you will not miss any major abnormalities in electrocardiograms (EKGs).
What is the meaning of the mnemonics?
Age, e.g. a 60-year patient is likely have a different pathology from a 30-year patient
Rate, e.g. fast or slow?
Axis, e.g. left or right?
Rhythm, e.g. regular or irregular?
Evaluate each EKG element as follows:
P wave, e.g. peaked or absent? PR interval - short or prolonged?
Q wave, e.g. deep Q wave? QT interval - - short or prolonged?
R wave, e.g. tall? look at QRS complex width for RBBB or LBBB
ST segment, e.g. elevation or depression?
T wave, e.g. peaked or inverted? U wave?
Drugs , e.g. Digoxin, tricyclic antidepressants
Rhythm and rate abnormalities, e.g. AV block of 1,2,3 degree, AFib, SVT? Interval prolongation?
Infarct? Deep Q wave?
Infection, e.g. pericarditis
Enlargement, e.g. LVH, RVH, left or right atrium enlargement?
Electrolyte disturbances, e.g. hyperkalemia, hypokalemia, hypercalcemia,
Endocrine causes, e.g. hypothyroidism