Speed = 25mm / sec => 1cm = 0.4 sec (x-axis)
Amplitude of 1 cm / mV => 1cm = 1mV (ordinate)
Normal values:
P wave -> 0.08 to 0.10 s; <0.25 cm
PR space -> from 0.12 to 0.20 s
QRS -> <0.08 s
General:
PR:
– Prolongation of the PR interval reflects the existence of an atrioventricular block
– The shortening of the PR interval reflects the existence of an accessory conduction bundle connected in parallel normal conduction pathways.
– A short PR interval with hooking the upstroke of the QRS (Δ wave) broad QRS with secondary repolarization disorder reflects the existence of WPW syndrome (associated with an accessory bundle atria and myocardium: beam Kent).
– A short PR kink free space QRS reflects the existence of a trendy accessory pathway between the atria and the bundle of His.
– The sub-shift (offset sub-PQ) is observed in two situations: infarction of the right atrium and acute pericarditis.
ST:
Sub-lag:
– Lesions subendocardial (angina attack)
– Hypokalemia
– Impregnation digitalis (cupuliforme sub-offset)
Sus-unsealing:
– Convex => subepicardial injury (acute MI or angina phase Variant) -> mirror image
– Concave => acute pericarditis (first stage)
T:
– IDM: succession in time of a subendocardial lesion (T-wave ample, sharp and symmetric) then appeared in late phase of a sub-epicardial lesion (negative T wave) that persists (sequel).
– Full and symmetric T wave: hyperkalemia; LVH with diastolic syrcharge ….
– Inverted T wave or food hypokalemia; LVH with systolic overload; acute pericarditis (stage 2) ….
QT: “EXTENSION”
– Hypokalemia -> causes the most common.
– Iatrogenic: kaliuretic diuretic, amiodarone, an antiarrhythmic class Ia (quinidine); quinine; tricyclic antidepressants;phenothiazine.
– Other: Hypocalcemia; hypomagnesemia
QRS:
– A widening of QRS translated into general rule branch block; rarely WPW syndrome.
