Cardiovascular ECG Interpretation Notes PDF

CARDIOVASCULAR 1. ECG INTERPRETATION I. SYSTEMATIC APPROACH TO ECG INTERPRETATION A. STEPWISE APPROACH E. APPROACH TO INTERVALS B. APPROACH TO HEART RATE...

CARDIOVASCULAR 1. ECG INTERPRETATION I. SYSTEMATIC APPROACH TO ECG INTERPRETATION A. STEPWISE APPROACH E. APPROACH TO INTERVALS B. APPROACH TO HEART RATE F. APPROACH TO P-WAVES C. APPROACH TO RHYTHM G. APPROACH TO QRS WAVES D. APPROACH TO AXIS H. APPROACH TO ST SEGMENT AND T-WAVES I. Systematic Approach to ECG Interpretation A. Stepwise approach 00:21 B. Approach to Heart Rate 01:56 1. Methods Used to Determine Heart Rate a) R-Wave Method First: Assess the number of R-waves in R-Waves x 6 (11 x 6 =66 bpm) the rhythm strip Second: Take the number of R-waves and multiply by 6 Third: # of R-waves x 6 = Heart rate b) Box Method First: Assess the number of boxes between the R-R interval o 1 box distance = 300 bpm Third: 300/ Number of boxes between R-R interval = Heart rate ECG Interpretation CARDIOLOGY : Note #1 1 of 11  C. Approach to Rhythm 04:08 1. Approach to the Tachycardic Rhythm a) Obtain Characteristics of QRS Complex Narrow QRS → < 120ms Wide QRS → > 120ms b) Obtain Characteristics of RR Interval Regular → Same RR Interval throughout rhythm strip Irregular → Variable RR Interval throughout rhythm strip Monomorphic VENTRICULAR TACHYCARDIA Wide QRS Complex TORSDAES DE POINTES (PMVT) VENTRICULAR FIBRILLATION 2 of 11 CARDIOLOGY : Note #1 ECG Interpretation 2. Approach to the Bradycardic Rhythm 09:34 a) Obtain Duration of PR Interval Normal PR interval → 160-200ms Prolonged PR-Interval → > 200ms b) Obtain the Presence of QRS Complexes Dropped QRS → 2nd degree AV block and beyond ECG Interpretation CARDIOLOGY : Note #1 3 of 11  D. Approach to Axis 12:26 1. Method of Determining the Axis a) Assess Lead I If QRS is (+) → (+) in Lead I If QRS is (-) → (-) in Lead I b) Assess Lead aVF If QRS is (+) → (+) in Lead aVF If QRS is (-) → (-) in Lead aVF NORMAL AXIS 2. Mechanism of Left Axis Deviation Delayed Depolarization of Left Ventricle → Electrical activity Left Ventricular Hypertrophy from the Right bundle branches has to then move in the direction of the LV → This creates a vector pointing toward the left ventricle wall Left Bundle Branch Block LEFT BUNDLE BRANCH BLOCK (LBBB) Left Anterior Fascicular Block LEFT AXIS DEVIATION 4 of 11 CARDIOLOGY : Note #1 ECG Interpretation 3. Mechanism of Right Axis Deviation Delayed Depolarization of Right Ventricle → Electrical activity from the Left bundle branches has to then move in the direction of the RV → This creates a vector pointing toward the right ventricle wall Right Bundle Branch Block Right Ventricular Hypertrophy RIGHT BUNDLE BRANCH BLOCK (RBBB) RIGHT VENTRICULAR HYPERTROPHY Left Posterior Fascicular Block 4. Mechanism of Extreme Right Axis Deviation Depolarization of the ventricles first → Electrical activity from the ventricles moves in the direction of the atria → This creates a Ventricular Tachycardia vector pointing toward the right atrial/ventricular wall EXTREME RIGHT AXIS DEVIATION ECG Interpretation CARDIOLOGY : Note #1 5 of 11  E. Approach to Intervals 16:08 1. Obtain Duration of PR Interval Normal PR interval → 160-200ms Short PR-Interval → < 160ms Prolonged PR-Interval → > 200ms Suspect WPW Suspect AV Blocks o ↓PR interval o Wide QRS o Delta wave 1ST DEGREE AVB 2ND DEGREE AVB (MOBITZ I) 2ND DEGREE AVB (MOBITZ II) Delta wave Excessi ve P Wave (Atrial Rate) Wide QRS Complex 3RD DEGREE AVB (Ventricular Rate) PR interval 120 ms 2. Obtain QT Interval Normal QT-Interval → 360-440ms for men and 360-460ms for women Prolonged QT-Interval → > 500ms Short QT interval → < 340ms o High risk for Torsades de Pointes > 1/2 of R-R Interval LONG QT INTERVAL SHORT QT INTERVAL 6 of 11 CARDIOLOGY : Note #1 ECG Interpretation  F. Approach to P-waves 19:43 LEFT ATRIAL ENLARGEMENT P Wave ≥ 2.5 mm RIGHT ATRIAL ENLARGEMENT ECG Interpretation CARDIOLOGY : Note #1 7 of 11  G. Approach to QRS Complex 21:57 LEFT BUNDLE BRANCH BLOCK (LBBB) RIGHT BUNDLE BRANCH BLOCK (RBBB) 8 of 11 CARDIOLOGY : Note #1 ECG Interpretation  RIGHT VENTRICULAR HYPERTROPHY ECG Interpretation CARDIOLOGY : Note #1 9 of 11  I. Approach to ST Segment and T-Waves 25:56 1. Approach to ST Segment ST Depression → > 0.5mm (½ a small box) below the J-point in 2 contiguous leads Horizontal Down-Sloping Up-Sloping > 0.5 mm in V2/V3 > 1 mm in all other leads If in 2 contiguous leads, more likely to indicate Cardiac Ischemia ST Elevation → > 1mm (1 small box) elevation above the J-point in 2 contiguous leads except for V2-V3, where it needs to be > 2mm (2 small boxes) elevation above the J-point o Concave ST elevation → Suggests Pericarditis o Convex ST elevation → Suggests STEMI Concave Convex > 1 mm in Limb Leads > 2 mm in Precordia l Leads 10 of 11 CARDIOLOGY : Note #1 ECG Interpretation 2. Approach to T-Waves T-wave Inversion → > 1mm (1 small box) depression below the isoelectric line in 2 contiguous leads Hyperacute T-Waves → > ⅔ the height of the QRS complex and a broad base > 1 mm in Limb Leads > 2 mm in Precordia l Leads ECG Interpretation CARDIOLOGY : Note #1 11 of 11