PACE:
* normal: regular, each QRS is preceded by a P wave (sinus rhythm).
* anomalies: irregular, no P wave before QRS.
FREQUENCY:
* normal: between 50 and 100 / min.
* anomalies:
– f> 100 / min: tachycardia.
F <50 / min: bradycardia.
P WAVE:
* normal: duration in D1 <0.12 s, amplitude in D2 <2 mm, positive in D1, D2, D3.
* anomalies:
– absence: sinoatrial block, BAV III, fibrillation, flutter, average nodal rhythm.
– amplitude> 2 mm in D2, D3, VF and diphasic in V1: right atrial hypertrophy.
– duration> 0.12 s: left atrial hypertrophy or interauricular conduction disorder.
– double hump aspect: HAG or intra-auricular conduction disorder.
– retrograde D2-D3-VF: lower nodal junctional rhythm.
SPACE PR:
* normal: duration = 0.12-0.20 s, isoelectric.
* anomalies:
– duration <0.12 s: Wolff Parkinson White, superior nodal rhythm.
– duration> 0.20 s: atrioventricular block I or II (Mobitz I).
Q WAVE:
* normal: duration <0.04 s, amplitude <25% of R, q in DIII disappearing in deep inspiration.
* anomalies:
– duration> 0.04 s and amplitude> 25% of R: old IDM.
Absence q in V5-V6: BBIG or BBGC.
– Q in D1: HBAG.
QRS COMPLEX:
* normal: duration <0.10 s, axis = [-30 ° to + 120 °].
* anomalies:
– duration> 0,10-0,12 s: BBID, BBIG
– duration> 0.12 s: BBCD, BBCG, ESV, ESA with functional block (aberration), TPSV + pre-existing or functional block, WPW, TV, hyperkalemia.
– delay intrasecoid deflection of +0.05 s in left precordial: BBG.
– intrasecoid deflection delay of +0.03 s in precordial straight lines: BBD.
– axis> -30 °: HBAG, axis> + 120 °: HBPG.
– R in V1-V2 and S in V5-V6 and right axial deviation: right ventricular hypertrophy.
– R at V6 and S at V1 and left axial deviation: left ventricular hypertrophy (Sokolow index: SV1 + RV5> 35 mm).
– Wide R in V6 and QS in V1: BBCG.
– RSR ‘: BBCD.
– S in D3: HBAG.
– aspect S1-Q3: sign of gravity of the pulmonary embolism.
ST SEGMENT:
* normal: isoelectric.
* anomalies:
– its offset encompassing the T wave (Pardee wave): IDM.
– overdose> 2 mm: subepicardial lesion, pericarditis.
– under offset> 2 mm: endocardial lesion.
Concave cupula upwards: digitalis, quinidine, hypokalemia.
– descending, sub-shifted: BBGC.
– ascending, over-shifted: BBCD.
– Osborn J wave in case of hypothermia.
QT SEGMENT:
* normal: time proportional to the frequency (use the ECG rule), between 0.35 and 0.45 s for a normal frequency.
* anomalies:
– pseudo-prolongation of QT (U-wave): hypokalemia.
– lengthening: hypocalcemia, alkalosis, hypothermia, Cordium, quinidines, other antiarrhythmics.
– shortening: hypercalcemia, hyperkalemia, acidosis, digitalis.
T WAVE:
* normal: asymmetric, not pointed, axis = [-10 to + 70 °], negative in VR +/- V1.
* anomalies:
– giant, pointed, symmetrical: subendocardial ischemia, hyperkalemia, pulmonary embolism.
– negative, deep, symmetrical: subepicardial ischemia.
– negative, asymmetric left precordial (V5, V6, VL): left ventricular systolic hypertrophy.
– negative, asymmetrical: repolarization disorders after ESV, BBDC if V1, V2, BBGC if V5, V6.
U WAVE:
* normal: absent.
* anomalies:
– U wave presence with flat or negative T wave: hypokalemia.
