Cardiovascular Diseases: High Yield Concepts in Cardiac Dysrhythmias Flashcards
Physiologic basis for normal ECG tracing
P-Wave: atrial depolarization
QRS complex: ventricular depolarization
T Wave: ventricular repolarization
Master pacemaker of the heart
Sinoatrial (SA) Node
Causes depolarization of the SA Node
Calcium influx (Sodium influx will merely bring potential closer to threshold; however, sodium is still the determinant of heart rate)
Chronotropic Incompetence
Failure to increase heart rate during exercise, alternatively defined as:
- unable to achieve 85% of predicted maximal heat rate at peak exercise
- unable to achieve a heart rate >100 beats/min with exercise
Maximal HR with exercise
The only electrical connection between the atria and ventricles
AV node
Most common arrythmia mechanism
Reentry
Only reliable therapy for symptomatic bradycardia in the absence of extrinsic and reversible etiologies
Permanent pacemaking
Most rapid conduction in the heart
His bundle and bundle branches
Most expeditious technique in the management of AV conduction block
Transcutaneous pacing
Most common arrythmia identified during extended ECG monitoring
Atrial premature Complexes
Most common sustained arrythmia
Atrial Fibrillation
Mobitz Type I
Has prolongation of PR interval before dropped QRS complex
Mnemonic: Think of the Roman Numeral I that gets taller —> PR prolongation in Mobitz I
Mobitz Type II
Has no prolongation of PR interval before dropped QRS complex
Mnemonic: Think of the Roman Numeral II with equal heights between the two letter “I”s —> no PR rolongation in Mobitz II
Duration that distinguishes sustained from nonsustained ventricular tachycardia
> 30 seconds
Most common arrythmia post-MI
Premature Ventricular Contraction (PVC)
