JAGDISH. K

PROF. DR. A. GOWRISHANKAR’S UNIT

ECG OF THE WEEK

30 yr old male was brought with the chief complaints of fever, altered sensorium for the past 3 days.

Patient was apparently alright 3 days ago.

Known type 1 diabetic on Insulin.

Examination

Patient was febrile, dyspneic, tachypneic, disoriented

Pulse : 110/minBP : 100/60 mm of hgRR : 38/minCNS :

disorientation + Neck rigidity +

Other systems : normal

ECG

ECG changes in electrolyte imbalance is not very predictable.

Change depends on the inter individual variation & on the other electrolytes too.

However certain ECG features often develop in conjunction with increased / decreased potassium concentration so that ECG may be frequently utilised for electrolyte disturbances particularly if the interpreter is thinking of electrolyte disturbances.

Accuracy of observation is enhanced if Control tracing available

Serial tracings done

Hyperkalemia

It has not been definitely established that the changes are due to

1. Intracellular K+ changes2. Gradient across cell membrane3. Potassium level in the serum alone

Action Potential

Atrial

SA Nodal

Ventricular

Similarities vs Differences

K+ changes & Action Potential curve

Changes during depolarisation & resting membrane potential

Changes during repolarisation

ECG changes

Short QT interval

Peaked T wave

ST segment depression

Lowering & widening of P wave

Prolonged PR interval

QRS widening

Short R wave & deep S wave

Marching of QRS & T wave towards each other

The Nadir of S wave & peak of T wave is connected by a straight line.

Sine wave pattern

Atrial fibrillation & Atrial arrest

Sinoventricular rhythm

Effect of other electrolytes

Low Na+ High Na+

Low Ca2+ High Ca2+

ECG

Sine wave