Ecg waves question? -

1) if a patient has ischaemic heart disease they have a prolonged pr interval over 0.2 seconds, due to a problem with conduction in the heart. where might the impulses be delayed to cause the extended pr interval? 2) in patients with pulmonary hypertension, blood pressure in the lungs is much higher than normal. their ecg has a trace with a large P wave. suggest which pat of the heart will be enlarged in a person with this condition and why?

1) delay in conduction of the impulse thru the atrial tissue...PR interval measures the time of conduction thru the atria... 2) P wave is the ECG picture of an impulse which is generated by the SA node...however lead placement may give a different picture = different size = different deflection... right atrial enlargement due to the increased pressure needed to pump blood to/thru the high pressured lungs...

P wave represents right amp; left atrial contraction. PQ interval , also called PR interval is the conduction of impulse through AV node and bundle of His. This is a rare case. More commonly is ST depression that shows myocardial ischemia, Pulmonary hypertension causes hypertrophy of right ventricle; high blood pressure causes hypertrophy of left ventricle. ECG cannot give specific reading for this myocardial hypertrophy.. It is better using echo-cardiography, and the thickness of right ventricle wall can be measured more accurately.

1. Delay in condution occurs in atrial muscles and anywhere between the sa node and av node due to ischemia. 2. right atrium due to increased resistance in pulmonary circulation

1. the delay is likely below the sinus node and prior to the bundle of his. Somewhere in the atria, delaying the impulse and widening the pr interval. 2. the ventricles will be enlarged as they must work very much harder to push the blood through the lungs and out to the rest of the body.