Q waves never significant in aVR not significant in V1 unless with abnormalities in other precordial leads not significant in III unless with abnormalities in II, aVF more reliable if associated with ST changes Not significant in V1-V3 if (+) LBBB, but significant if (+) RBBB Ĭriteria for Pathologic Q waves ≥ 0.04 sec in duration ≥ 25% of the R wave amplitude Timing of MI/ECG 0-6 hours 6-24 h 24 -72 h 72 h – 6 weeks > 6 wkĭifferentials for ST elevation Acute pericarditis Ventricular aneurysm Severe LV wall hypokinesia Early repolarization changes Variant (prinzmetal) angina Myocardial infarction Criteria (any) ST elevation ≥ 2 Chest leads: ≥ 2 mm elevation or ≥ 2 Limb leads: ≥ 1 mm elevation Q waves ≥ 0.04s (1 small square) Myocardial Ischemia 1 mm ST-segment depression Symmetrically/inverted T waves Abnormally tall T waves Normalization of abnormal T waves Prolongation of QT interval Arrhythmias, BBB, AV blocks or electrical alternans RRAHIM Components of ECG interpretation Rate Rhythm Axis Hypertrophy Ischemia and Infarction Miscellaneous (normal variants) RAE (p pulmonale) 2 Methods V1: tall initial component of P wave ≥ 2mm wide and ≥ 2 mm tall Any Lead: P wave ≥ 2.5 mm tall LAE (p mitrale) 2 Methods V1: wide terminal component of P wave ≥ 1 mm wide (0.04 s) and ≥ 1 mm deep Any lead: P wave wider than 0.12s or with a ≥ 1 mm notch in the middle RVH Criteria RAD of ≥ +110, with any of the ff: V1: R wave > S wave COPD RBBB True posterior infarction WPW Deep S wave in V5-6 COPD ST depression and T wave inversion in V1-3 SR, LVH with Strain Pattern, Old Anteroseptal Wall MI LVH criteria 3 Methods 1) S wave in V1 + R wave in V5/6 > 35mm 2) R in AVL > 11mm 3) Romhilt and Estes Criteria (best) Hypertrophy Six Possibilities No hypertrophy LVH RVH LAE RAE combination Normal (-30 to +90) RAD Indeterminate LADĪxis - 90 AVF indeterminate LAD ± 180 0 I RAD normal (-30 to +90) + 90 Īxis Differentials WPW syndrome WPW syndrome LPFB LAFB Pulmonary embolism LBBB Lateral wall MI Inferior wall MI RVH (COPD, cor pul) LVH (HTN) N variant: thin, tall N variant: short, fat RAD LAD Third-degree AV block Left or Right Bundle Branch Block Complete Incomplete Ventricular Arrhythmias Premature Ventricular Depolarization (PVD) Ventricular Tachycardia (V-tach) Sustained Non-sustained Ventricular fibrillation (V-fib) Īxis Determination get the average QRS vector from the isoelectric baseline in Leads I and AVF if the average QRS vector is above baseline -> (+) QRS deflection if the average QRS vector is below baseline -> (-) QRS deflection Īxis - indeterminate + - RAD - + LAD + + Normal Axis AVF Lead 1 Rhythm Identify the P wave Check relation of P wave to QRS Normal: P wave is before QRS SVT, heart blocks: P wave after QRS or burried Check PR interval ( 0.12 - 0.20s ) Shortened: WPW Prolonged: 1 st and 2 nd degree AV block Ĭheck QRS duration (Widened: bundle branch blocks Check relation of R-R and P-P int PP PP > RR: AV dissociation Ĭommon Rhythm Interpretations Sinus rhythm Supraventricular arrhythmias Atrial fibrillation Atrial flutter Supraventricular tachycardia (SVT) Heart Blocks First-degree AV block Second-degree AV block Mobitz Type I (Wenckebach) Mobitz Type II Rate Mnemonic: 300, 150, 100, 75, 60, 50 Formula: 1500 / # of small boxes 300 / # of big boxes Bradycardia = Normal Rate = 60-100 bpm Tachycardia = >100 bpm RRAHIM Components of ECG interpretation R ate R hythm A xis H ypertrophy I schemia and Infarction M iscellaneous (normal variants) V1 = 4th ICS, R sternal border V2 = 4th ICS, L sternal border V3 = halfway between V2 and V4 V4 = 5th ICS, L MCL V5 = 5th ICS, anterior axillary line V6 = 5th ICS, L mid-midaxillary line V3R = halfway between V1 and V4R V4R = 5th ICS, R MCL Lead LocationsĬorrespondence Anteroseptal wall V1-V3 Lateral wall V5, V6 Anterior wall V3, V4 Septal wall V1, V2 High lateral wall I, aVL Inferior wall II, III, aVF Area LeadsĪrea Leads RV wall V3R and V4R Posterior LV wall Mirror image of V 1/2 Diffuse/global/massive Almost all leads Inferolateral wall V5, V6, II, III, aVF Anterolateral wall V3-V6, I, aVL

Cualteros, M.D.ĮCG Indications determine cardiac rate define cardiac rhythm diagnose old or new MI identify intracardiac conduction disturbances aid in the diagnosis of IHD, pericarditis, myocarditis, electrolyte abnormalities and pacemaker malfunction

Ivcd ecg images