Abnormal EKG Flashcards
What are the key components of a normal ECG?
- A normal ECG consists of P-waves (atrial depolarization)
- QRS complex (ventricular depolarization)
- T-wave (ventricular repolarization).
What is an arrhythmia, and what are common symptoms?
An arrhythmia is an irregular heartbeat, often causing dizziness, fainting, chest pain, and difficulty breathing.
What is atrial fibrillation (A-fib) and what are its clinical signs?
a) A-fib is characterized by
- erratic quivering of the atrial muscle
- irregular RR intervals
- absent P-waves
b) It reduces cardiac output and can cause palpitations, fatigue, and shortness of breath.
What is atrial flutter, and what distinguishes it from A-fib?
- Atrial flutter is marked by a rapid atrial rate (250-350 bpm) and saw-tooth P-waves.
- It is typically more regular than A-fib but can progress to A-fib.
What are the clinical flags associated with ventricular arrhythmias?
- Green flag: Intermittent unifocal PVC.
- Yellow flag: Couplet PVC, trigeminy.
- Red flag: More than 6 PVCs/min, 3 or more in a row, V-fib, or V-tach.
What are premature ventricular complexes (PVCs) and their clinical significance?
- PVCs are premature beats originating from ectopic foci in the ventricles.
- They are benign unless frequent (>6/min), paired, or multifocal, which can lead to serious arrhythmias.
What is ventricular tachycardia (V-tach), and why is it life-threatening?
- V-tach involves 3 or more PVCs in a row, with a ventricular rate >150 bpm.
- It is life-threatening because it impairs cardiac output and can degenerate into V-fib.
What are the different types of heart blocks?
-) Bundle Branch Blocks: Part of the hearts bundle-branch system is blocked
-) Right BBB: Travels rapidly down left side and then delayed impulse to right side across the septum
-) Left BBB: Travels down right side first then slowly depolarizes the left
-) 1st degree AV block: Initiated in SA node but delayed to AV node
-) 2nd degree AV block: Disturbance in AV junction that prevents conduction of some impulses through the AV node
- Mobitz Type I block (Wenckebach block)
- Mobitz Type II block: Consecutive PR intervals are the same and normal,followed by nonconduction of one or more impulses
-) 3rd degree AV block (complete heart block): All impulses initiated above the ventricles are not conducted to the ventricle
- Blocked at the AV node
What is a third-degree AV block, and why is it a medical emergency?
- In a third-degree AV block, there is no communication between atria and ventricles.
- Atria and ventricles beat independently, requiring immediate pacemaker intervention.
What is a right bundle branch block (RBBB), and how is it identified?
RBBB is identified by a widened QRS complex (>0.12 sec) and an RSR’ pattern (bunny ears) in leads V1 and V2.
What is a left bundle branch block (LBBB), and how does it present clinically?
LBBB shows a widened QRS complex with ST-T changes, opposite deflection of the QRS complex in V5 and V6, and always indicates underlying heart disease.
What is the difference between STEMI and NSTEMI?
STEMI is a full-thickness myocardial infarction with ST-segment elevation.
NSTEMI involves ST depression without full-thickness damage.
What are the key signs of ST-segment elevation and depression on an ECG?
- ST-segment elevation indicates transmural infarction
- ST depression suggests subendocardial ischemia or impending infarction.
What is the clinical significance of Q-wave changes on an ECG?
Q-wave changes indicate necrosis, with deep and wide Q-waves suggesting irreversible myocardial damage.
What is T-wave inversion, and what does it indicate after an MI?
T-wave inversion occurs after a myocardial infarction due to delayed repolarization, often appearing days after the event.
