ECG Practical Session Second Year

ECG Practical Session (Second Year)

•  The presentation covers ECG interpretation for myocardial infarction (MI) and other cardiac conditions.
•  Myocardial infarction is a critical cardiac condition where blood flow to the heart muscle is blocked resulting in cell death.
•  The coronary system delivers blood to the heart muscle and comprises the aorta, pulmonary artery, and various coronary arteries (including the right coronary artery, left main artery, left anterior descending coronary artery, and circumflex coronary artery).
•  Acute Coronary Syndromes (ACS) are conditions that fall under myocardial infarctions. ACS can be categorized into ST-Elevation Myocardial Infarction (STEMI) & Non-ST-Elevation Myocardial Infarction (NSTEMI).
•  STEMI includes transmural (Q-wave) and NSTEMI includes subendocardial (non-Q-wave) types.
•  ECG changes associated with MI include hyperacute T waves, ST segment elevation, and pathological Q waves.
•  Hyperacute T waves are the earliest sign and characterized by prominent, symmetrical T waves that typically precede ST elevation. They are usually transient.
•  ST segment elevation occurs when the ST segment is raised above the baseline level, usually in leads related to the particular muscle damage. This is a crucial diagnostic feature for determining the location and severity of the MI.
•  Pathological Q waves develop as a result of myocardial necrosis. The R wave loses amplitude, and a new Q wave forms. Q waves can be a lasting/permanent marker after MI healing.
•  The location of the ST segment elevation or other ECG changes can indicate the affected heart wall (inferior, anterior, or lateral).
•  Specific leads on an ECG relate to specific locations in the heart. (e.g., leads II, III, and aVF are associated with the inferior wall, and leads V1-V4 with the anterior wall).
•  Reciprocal ST depression in leads remote from the site of the infarction can frequently be a highly sensitive indicator of infarction. This depression is frequently horizontal or downsloping.
•  Infarction resolution is characterized by diminishing ST elevation and T wave inversion.
•  Chamber enlargements (such as left ventricular hypertrophy or right ventricular hypertrophy) can be identified through changes in the QRS complex size and shape (voltage) in an ECG.
•  Bundle branch blocks (e.g., right bundle branch block (RBBB) and left bundle branch block (LBBB)) result in characteristic QRS complex widening and morphology changes. Key features to recognize on an ECG include the presence or absence of an rSR′ or qsR′ appearance in the respective leads.
•  Arrhythmias (e.g., premature atrial contractions (PACs), premature ventricular contractions (PVCs), sinus tachycardia, atrial fibrillation (AF), supraventricular tachycardia (SVT), ventricular tachycardia, heart block (first-degree, second-degree, and third-degree)) can be identified in an ECG rhythm strip.
•  Specific arrhythmia types are associated with distinct characteristics in the ECG rhythm strip, such as irregular R-R intervals in atrial fibrillation or various QRS morphologies.