DR. PRIYA KUBENDIRANM-1 UNIT

PROF DR.RUCKMANI’S UNIT

BRIEF HISTORY

A 40 year old male was admitted on 10.08.09 with

c/o acute watery diarrhoea – 3 days

No H/O vomiting/feverNo H/O any chest discomfort

H/O recurrent episodes of diarrhoea over the past 4 months.

Not a k/c of DM/SHT/PT/BA/IHD

O/E : conscious, oriented afebrile pallor + mild dehydration + PR – 110/min BP – 96/70 mm Hg

RS – NVBS +, no added sounds CVS – S1 S2 +, no murmur P/A – soft, no organomegaly CNS- NFND

ECG TAKEN ON 10.08.09

HR – 100/minNormal sinus rhythmAxis – 70˚PR interval – 0.16 sQRS interval – 0.08 sQU – 0.48 s

Lab investigations : B.urea - 36 mg/dl S.creatinine – 0.7 mg/dl S.electrolytes Na – 138 meq/l Cl - 90 meq/l Hco3 – 20 meq/l K - 2.2 meq/l

ELISA for HIV1 - positive

Cardiac evaluation

Echocardiogram:No RWMANormal Echo study

After adequate hydration, i.v antibiotics and corrective measures for hypokalemia

oral KCl 15 ml tds i.v - 20 mEq/day

3 days later repeat s.potassium – 4.2 mEq/L

A repeat ecg was taken

REPEAT ECG ON 14.08.09

HR – 43/minNormal sinus rhythmQRS axis - 60˚PR interval – 0.16 sQRS interval – 0.08 sQT interval – 0.48QTc – 0.41 s

ECG CHANGES IN HYPOKALEMIA

The ecg changes are due to

DELAYED VENTRICULAR REPOLARIZATION

Diagnosis is therefore based on ST segment, T wave & U wave abnormalities

T wave -progressive dimunition in amplitude, may

eventually disappear - a remnant of T maybe visible as a slight

irregularity (minimal upward bump) on ST segment

U wave progressive increase in amplitude &

maintains its rounded appearance may get superimposed on T -TU complexST segment ST depression is seen in all leads which

may be horizontal or concave upwards

Prominent U waves combined with ST segment depression & flattened T waves –

ROLLER COASTER EFFECT

QT interval U wave may be mistaken for a T wave

leading to an incorrect diagnosis of prolonged QT interval

QT interval is usually unchangedP wave increase in amplitude/ durationPR interval 1st degree AV block is common Prolongation may lead to superimposition

of P on TU – TUP complex 2nd degree AV block of Wenkebach type

may be seen

QRS complex decreased voltage & increased duration

Arrythmias Atrial & ventricular ectopics Atrial tachycardia with block with AV

dissociation Ventricular tachycardia Ventricular fibrillation Torsades de pointes

1. ST depression ≥ 0.5 mm2. U wave amplitude > 1 mm3. U wave amplitude > T wave amplitude in

same lead

Typical ecg : 3 features in 2 leads

Compatible ecg : 2 features- U wave related characteristics is present