ECG Practical Session for Second Year PDF

ECG practical session “for second year” Myocardial infarction Coronary system  Clinically speaking ………. Acute Coronary Syndrome is divided into …. –ST Elevation (Transmural or Q-wave), or –Non-ST Elevation (Subendocardial or non-Q-wave)  There are two distinct patterns of...

ECG practical session “for second year” Myocardial infarction Coronary system  Clinically speaking ………. Acute Coronary Syndrome is divided into …. –ST Elevation (Transmural or Q-wave), or –Non-ST Elevation (Subendocardial or non-Q-wave)  There are two distinct patterns of ECG change ST Elevation Non-ST Elevation Acute ST-Elevation Myocardial Infarction Importance of ECG: 1. Diagnosis 2. Localization 3. Progression  (i) Hyperacute T waves Earliest sign Prominent symmetrical T waves Usually transient, followed by ST elevation  (ii) ST segment elevation ST elevates and loses its normal concavity Later became convex upwards Sometimes fusion of QRS. ST and T produce a giant R wave (Tombstone) Site of ST segment elevation  Septal Wall V1, V2 – Along sternal borders – Look through right ventricle & see septal wall I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 So.. Septal infarction will show in V1 & V2 I aVR V1 V4 II aVL V2 V5 III aVF V3 V6  Anterior Wall V3, V4 – Left anterior chest –  electrode on anterior chest I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 So Anterior Wall infarction will show in V3 & V4 I aVR V1 V4 II aVL V2 V5 III aVF V3 V6  Lateral Wall……. I and aVL – View from Left Arm  – lateral wall of left ventricle I aVR V1 V4 II aVL V2 V5 III aVF V3 V6  ……Lateral Wall V5 and V6 – Left lateral chest – lateral wall of left ventricle I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 So Lateral Wall infarction will show in I, aVL, V5, V6 I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 Lateral Wall  Inferior Wall II, III, aVF – View from Left Leg  – inferior wall of left ventricle I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 So Inferior Wall infarction will show in II,III and aVF I aVR V1 V4 II aVL V2 V5 III aVF V3 V6 Inferior Wall  N.B. Reciprocal ST depression ST depression in leads remote from the site of an acute infarct Highly sensitive (90%) indicator of infarction Seen with 70 % of inferior and 30 % of anterior infarctions Typically the depressed ST segment tend to be horizontal or downsloping The pathogenesis is uncertain, may be due to extension of ischemia, or coexisting remote ischemia or electrical phenomenon “mirror image” N.B. Resolution of ST & T changes As infarction evolves, ST elevation diminishes and T wave begin to invert This may take few weeks to settle and may persist if aneurysm is formed T wave inversion may persist as a permenant sign of infarction  (iii) Pathological Q waves Loss of R wave amplitude and new Q waves Due to loss of viable myocardium under the recording electrode Firm evidence of myocardial necrosis Sometimes with contraction of scar tissue during healing, q waves disappear CHMABER ENLARGEMENT  Left Ventricular Hypertrophy Compare these two 12-lead ECGs. Normal Left Ventricular Hypertrophy Answer: The QRS complexes are very tall (increased voltage) S in V1 + R in V6 > 7 big boxes Right Ventricular Hypertrophy Tall R in V1 and deep S in V6  Bundle Branch Blocks With Bundle Branch Blocks you will see two changes on QRS complexes + repolarization changes 1. QRS complex widens (> 0.12 sec). 2. QRS morphology changes (varies depending on ECG lead, and if it is a right vs. left bundle branch block). Left BBB LBBB Arrhythmia workshop Remember: Premature beats: PACs → early beats with normal QRS complexes PVCs → early beat with wide abnormal QRS complexes Bigeminy/trigeminy vs. Couplets/triplets  Narrow complex tachycardia regular Irregular Sinus tachycardia SVTs AF  Regular Wide complex tachycardia: Ventricular Tachycardia Heart block Sinus tachycardia AF SVT AF PVCs - bigeminy SVT SVT Monomorphic Ventricular tachycardia Monomorphic Ventricular tachycardia Ventricular fibrillation Sinus bradycardia First degree heart block Wenckebach Third degree HB Third degree HB Wenckebach