Non cardiac conditions and ECG's

Question 1

What are non-cardiac conditions that cause ECG changes

Answer 1

-cerebral haemorrhage
-PE
-hypothermia
-hyper/hypokalaemia
-metabolic disturbances

Question 2

What is bazett’s formula

Answer 2

QTc= QT/ square root of RR
-male normal= less than 440ms
-female normal= less than 460ms

Question 3

ECG changes with cerebral haemorrhage

Answer 3

-bradycardia
-cerebral T waves- deep, wide, massive, usually negative
-prolonged QT interval

Question 4

ECG changes with PE

Answer 4

Need a few of these to be met for PE diagnosis
-sinus tachycardia
-right ventricular strain pattern
-S1 (dominant S wave in 1), Q3 (Q wave in lead 3), T3 pattern (inverted Q wave in lead 3)
-RBBB
-right axis deviation
-non specific ST segment and T wave changes
-inverted T waves in lead 3 and V1- helps to differentiate from ACS

Question 5

Hypothermia ECG changes

Answer 5

-bradyarrhythmia’s
-osbourne waves- small peak after QRS and before T wave
-prolonged PR, QRS and QT interval
-shivering artefact
-ventricular ectopics

Question 6

Patients at high risk from hyperkalaemia

Answer 6

-renal failure
-haemodialysis patients
-patients taking ACE inhibitors
-patients taking potassium sparing diuretics
-potassium supplements

Question 7

What happens in hyperkalaemia

Answer 7

-reduces myocardial excitability
-this has a depressant effect on conduction and contractile cells
-leads to suppression of impulse generation by SA node and reduces conduction of AV node

Question 8

Hyperkalaemia ECG changes

Answer 8

-peaked T wave
-P wave widens and flattens
-bradyarrhythmia’s
-bundle branch blocks
-QRS widening with bizarre morphology

Question 9

ECG changes hypokalaemia

Answer 9

-increased P wave amplitude
-prolonged PR interval
-widespread ST depression and T wave flattening/ inversion
-U waves
-prolonged QT interval due to U wave
-tachyarrhythmias