ECG and arrythmias

ECG and Arrhythmias:


ECG changes in MI:
Early acute phase:
ST segment elevation
Hyperacute tall T waves
Fully evolved phase:
Large Q waves
Elevated ST segment begins to resolve
Inversion of T waves
Old infarction:
Large Q waves


ECG in constrictive pericarditis:


Low voltage waves and flattening or inversion of T waves


Causes of ST segment elevation :
1) Acute Mi
2) Prinzmetal angina
3) Ventricular aneurysm
4) Acute pericarditis
5) Early repolarization
6) LVH/LBBB
7) Brugada syndrome
8) DC cardioversion
9) Hyperkalemia
10) Hypothermia


Prolonged QT interval:
Hypocalcemia
Myocarditis
Acute rheumatic carditis
CVA
Drugs like quinidine, procainamide, disopyramide
Short QT interval:
Hypercalcemia
Vagal nerve stimulation
Hyperthermia
Digitalis toxicity


Digitalis toxicity:
Sign and symptoms;
Earliest manifestation is nausea and vomiting
Cachexia, weight loss
Neuralgias, gynecomastia, yellow vision, delirium
Hypokalemia , hpercalcemia ,thyroid disease ,hypomagnesemiaprecipitates digitalis toxicity
ECG changes:
Non paroxysmal atrial tachycardia with variable block is characteristic
Ventricular bigeminy and VPCs
Ventricular tachycardia and VF
Short QT interval
Treatment:
Stop the drug
Potassium supplementation
Phenytoin, b-blockers and lidocaine
Cardioversion for VF
FAB antibodies
No role of hemodialysis

ECG changes in Hypokalemia:
Prolonged PR interval
Prominent U waves
ST depression and flattening or inversion of T waves
ECG changes in hyperkalemia:
Tall peaked T waves
Prolonged PR and QRS interval
Loss of P waves
Sine wave pattern


WPW syndrome:
Short PR interval
Slurred upstroke of QRS complex or Delta wave
Wide QRS complex