ECG Strip Interpretation questions and answers well illustrated.

ECG Strip Interpretation questions and answers well illustrated. Normal PR segment length - correct answers.0.12 - 0.2 sec 3 - 5 small boxes Normal QRS interval - correct answers.0.06 - 0.1 sec 1 - 3 small boxes Normal P amplitude & duration - correct answers.< 0.12 sec (3 small boxes) < 0.25 mV (2.5 small boxes) causes of arrhythmias - correct answers.HISDEBS: hypoxia, ischemia/irritability, SNS, drugs, electrolytes, bradycardia, stretch (hypertrophy/enlargement) symptoms of arrhythmias - correct , "palpitations," light-headedness, syncope, angina, HF, sudden death Arrhythmias - 4 quick questions - correct answers.1. Normal P waves? 2. Wide QRS? (> 0.12 sec indicates pacemaker below Bundle of His) 3. One P for every QRS? 4. Normal rate & rhythym? Sinus arrhythmia - correct answers.Appearance is ALMOST NORMAL: Respiratory - Circulatory interaction Rate INCREASES with INSPIRATION (IN=IN) Sinus arrest - criteria - correct answers.Rate: Regular or Bradycardia P wave: Normal QRS: Normal Conduction: Normal Rhythm: Irregular: length of pause ≠ multiple of normal rate (random) Junctional Escape Beat/Rhythym - criteria - correct answers.Rate: Bradycardia P wave: Absent or Inverted P; if present, may occur during or after the QRS QRS: Normal Conduction: Escape beat: P-R interval < 0.12 seconds (if P present) Rhythm: Irregular when it occurs (late) If occurs 3 or more times in a row, is considered junctional escape rhythm Sinus exit block - criteria - correct answers.Rate: Regular or Bradycardia P wave: Normal QRS: Normal Conduction: Normal Rhythm: Irregular: length of pause = multiple of normal rate (Signal blocked leaving SA node; block is exactly equal to multiple of rate - one or more impulses "missed") PACs (premature atrial contractions/atrial premature beats) - criteria - correct answers.Rate: Regular underlying rate P wave: Abnormal - they originate from an ectopic pacemaker QRS: Normal Conduction: Normal (except for PACs) Rhythm: Irregular when PACs occur (early) PJCs (Premature Junctional Contractions) AKA: Junctional Premature Beats - correct answers.Rate: Regular underlying rate P wave: Absent or Inverted (like junctional escape) QRS: Normal Conduction: PJC: P-R interval < 0.12 seconds (if P waves are present) Rhythm: Irregular when PJCs occur (early) PSVT (Paroxysmal Supraventricular Tachycardia) AKA: AV nodal Re-entrant Tachycardia - correct answers.Rate: Tachycardia (usually 150 - 200) P wave: Absent or Inverted (like junctional escape) QRS: Normal (may be wide, pseudo R') Conduction: P-R interval < 0.12 seconds (if P) Rhythm: Regular (abrupt onset and termination) Carotid massage: slows or terminates Atrial flutter - correct answers.Rate:Atrial 250-350 Ventricular: 100 -175 P: Irregular or absent, often "saw tooth" QRS: Normal Conduction: AV Block (2:1 > 3:1, 4:1) Rhythm: Regular (usually) - Often underlying cardiac disease Carotid massage: increases block Atrial fibrillation - correct answers.Rate: Atrial 400-650; Ventricular usually 120 - 180 P wave: Not present; often wavy baseline QRS: Normal Conduction: Variable AV conduction Rhythm: Irregularly Irregular - chaotic, unpredictable depolarizations w/i atrium, no atrial kick - CAD, HTN, COPD, etc. Carotid massage: may slow ventricular rate MAT (Multifocal Atrial Tachycardia): - correct answers.Rate: Atrial varies, Ventricular 100-200 P wave: ≥ 3 different 'P' waves QRS: Normal Conduction: AV conduction, P-R intervals vary Rhythm: Irregularly irregular Carotid massage: no effect Etiology: longstanding COPD, etc. PAT (Paroxysmal (episodic) Atrial Tachycardia) - correct answers.Rate: 100 - 200; Ventricular 1:1 (or 2:1, 3:1, 4:1) P wave: Usually present, abnormal QRS: Normal Conduction: P-R interval varies (dt ectopic sites) Rhythm: Regular (warm up &/or cool down) Carotid massage: no effect, or only mild slowing bigeminy? - correct answers.1:1 ratio of normal:PVC trigeminy? - correct answers.2:1 ratio of normal:PVC PVCs (Premature Ventricular Contractions) - correct answers.Rate: Regular underlying rate (usually) P wave: Absent (or abnormal) in PVC QRS: PVC: wide > 0.12 seconds; shape is bizarre; T wave inversion Conduction: Normal before & after PVC Rhythm: Irregular; may occur in singles, couplets or triplets Reasons to worry about PVCs? - correct answers.- Frequency increasing - Runs of 3 or more consecutively - Multiple PVC foci - R-on-T Phenomenon - PVC in acute MI Multiple PVC foci - correct answers.Beats 1 and 4 are sinus in origin. The other three beats are PVCs. The PVCs differ from each other in shape (multiform), and two occur in a row. PVC - R on T - correct answers.A PVC falls on the T wave of the second sinus beat, initiating a run of ventricular tachycardia. Ventricular tachycardia - correct answers.Rate: 120 - 200 usually P wave: Usually absent (unrelated to the QRS) QRS: Wide & bizarre shape (PVCs) Conduction: No correlation between 'P' if present and QRS Rhythm: Regular or Irregular * Cannon A waves may be present Carotid massage: no effect Ventricular Fibrillation - correct answers.Rate: Not attainable P wave: Obscured by ventricular waves QRS: No true QRS Conduction: Chaotic electrical activity Rhythm: Irregularly Irregular Torsades de Pointes - correct answers.Rate: 120 - 200 usually P wave: Obscured by ventricular waves QRS: Wide QRS - "Twisting of the Points" Conduction: Ventricular only Rhythm: Slightly irregular 1º AV block - correct answers.Rate: Normal (usually) P wave: Normal QRS: Normal Conduction: P-R interval is > 0.2 seconds (delay) Rhythm: Regular 2º AV Block - Wenckebach/Mobitz Type I - correct answers.Rate: Normal or Bradycardia P wave: Normal & constant P-P interval QRS: Normal Conduction: P-R interval is progressively longer until P wave is blocked; the cycle begins again Rhythm: Irregular 2º AV Block - Mobitz Type II - correct answers.Rate: Bradycardia P wave: Normal & constant P-P interval QRS: Normal or widened (usually associated with a bundle branch block) Conduction: P-R interval normal or prolonged (constant); some P waves are not conducted to ventricles (varies) 3º AV Block - correct answers.Rate: Atrial 60-100; Ventricular 30-45 P wave: Normal with constant P-P interval ("marching through") QRS: Usually widened (depends on location of escape pacemaker) Conduction: Atrial & Ventricular activities are unrelated (complete block) Rhythm: Irregular Bundle branch blocks - general criteria - correct answers.Due to changes related to the block, cannot say there is hypertrophy - BBB will make it look like hypertrophy Rate: Regular or Bradycardia P wave: Normal usually QRS: Wide > 0.12 seconds Conduction: Block occurs in the right or left bundle branches (or both) Rhythm: Regular usually Right bundle branch block (RBBB) - correct answers.Right ventricular depolarization is delayed Criteria: - QRS complex > 0.12 seconds - RSR′ in V1 and V2 (rabbit ears) with ST segment depression and T wave inversion - Reciprocal changes in V5, V6, I, and aVL. Left bundle branch block (LBBB) - correct answers.LV depolarization is delayed Criteria: - Wide QRS > 0.12 - Broad (+/- notched) R waves, ST depression & T-wave inversion in I, aVL, V5, V6 - Broad S waves in V1, V2 - Left axis deviation may be present Ischemic signs - correct answers.- ST elevation or ST depression: > 1mm related to baseline (0.08 s (2 boxes) after QRS) - Also *symmetric* T-wave inversion in multiple precordial leads Other causes of ST elevation - correct ing transmural MI, Prinzmetal's angina, J point elevation, acute pericarditis, acute myocarditis, hyperkalemia, PE, Brugada syndrome, hypothermia RBBB - underlying - correct answers.May be otherwise normal (sometimes in athletes) LBBB - underlying - correct answers.Usually underlying cardiac disease Wolff-Parkinson-White Syndrome (WPW) - correct answers.- Bypass pathway (bundle of Kent) between atria & ventricles - No pause at AV node - short PR interval - Delta Wave: Slurred initial upstroke of R Short PR interval < 0.12 seconds Wide QRS > 0.1 second with delta wave WPW risks - correct answers.- PSVT dt reentrant pathway present; may be narrow QRS if via AV node & back up Kent, or wide (& hard to distinguish from V tach) if via Kent & back up AV node - a fib - Kent acts as free conduit for chaotic atrial activity; may lead to V fib Hyperkalemia - correct answers.- Evolution of (1) peaked T waves, (2) PR prolongation & P wave flattening, & (3) QRS widening. - Ultimately, the QRS complexes and T waves merge to form a sine wave, and ventricular fibrillation may develop. Hypokalemia - correct answers.- ST segment depression - Flattening (or inversion) of the T wave - Appearance of a U wave. Hypercalcemia - correct ened QT