7 Arrhythmias + EKG practice Flashcards
How would you classify this rhythm?
Atrial fibrillation
How would you classify this rhythm?
Atrial fibrillation
How would you classify this rhythm?
Ventricular tachycardia
How would you classify this rhythm?
Ventricular Fibrillation
How would you classify this rhythm?
Ventricular asystole
The length of action potential correlates with what part of the EKG?
The QT interval
How do drugs target fast versus slow response cells in the heart?
- Na blockers target fast response cells (rely on Na for depolarization)
- class I (quinidine)
- Ca blockers target slow response cells (rely on Ca for depolarization)
- verapamil, diltiazem
How does the recovery of excitability differ between fast and slow response cells?
Fast response= prompt recovery (ends with repolarization)
Slow response= delayed recovery (outlasts repolarization)
How does para/symp innervation affect fast and slow response cells?
- Fast response
- Catecholamine (SNS)= little effect on depolarization
- Acetylcholine (PS)= no effect on depolarization
- Slow response
- Catecholamine (SNS)= enhances depolarization
- Acetylcholine (PS)= significantly depresses depolarization
What are the 3 main mechanisms of arrhythmias?
- abnormal automaticity (enhanced/reduced)
- triggered automaticity (afterdepolarizations)
- reentry (abnormal impulse conduction… most common)
What 3 characteristics of an AP can be altered to increase the rate of automaticity?
- increase the slope of phase 4 (slow/leaky Ca depolarization before threshold)
- make the threshold potential more negative (easier to reach)
- make maximum diastolic potential (MDP; how negative the cell is repolarized to) more positive
Contrast early and late afterdepolarizations
- Early
- disrupts repolarization
- can progress to torsades de pointes
- Delayed/late
- occurs after repolarization
- triggered by leaky ryanodine receptors (increase Ca)
What is CPVT?
Catecholaminergic polymorphic ventricular tachycardia
**an inherited arrhythmogenic disease caused by a genetic mutation of the ryanodine receptor (results in the aberrant release of Ca from the SR)
What are the 3 requirements for establishing a reentrant circuit
- multiple parallel pathways
- unidirectional block
- conduction time > effective refractory period
Describe the mechanism of AVNRT
- AV Node Reentry
- Patient normally has sinus rhythm because slow pathway conduction is blocked due to collission with the fast
- A critically timed atrial premature beat allows conduction down the slow but not the fast pathway (fast still in refractory from previous beat)
- allows slow pathway to “reenter” and come up the fast pathway retrograde
- enters a cycle of continous atrial/ventricular depolarization
How does AVRT look on EKG? What are the common symptoms?
- Narrow QRS complex tachycardia
- Symptoms
- palpitations
- dizziness
- dyspnea
- chest pain
What are the 4 main ways antiarrhytmic drugs reduce spontaneous discharge in autonomic tissues?
- Decreased phase 4 slope
- Increased AP threshold (decrease # of Na channels)
- Increased maximum diastolic potential
- Increased AP duration
How would you classify this rhythm?
Atrial flutter
How would you classify this rhythm?
Slow-Fast AV nodal re-entrant supraventricular tachycardia
**Retrograde P waves in II
**ST and/or T wave abnormality consistent with myocardial ischemia
How would you classify this rhythm?
Sinus rhythm with 1st degree AV block
How would you classify this rhythm?
- Sinus rhythm
- Mobitz Type 1, 2nd degree AV block
- “5:4 nodal wenckebach”
- Acute Inferolateral wall myocardial infarction (ST elevation in II, III and avF)
How would you classify this rhythm?
Third degree AV block with ventricular escape (Atrial rate: 95/min, Ventricular rate: ~36/min)
How would you classify this rhythm?
- Sinus rhythm
- 1st degree AV block (PR interval ~210 msec)
- PVCs (with RBBB morphology)
- Possible Inferior wall MI (Q waves inferior leads)
How would you classify this rhythm?
Wide QRS tachycardia with LBBB / Inferior QRS axis
