written arrhythmia identification and ECG

P wave shows

atrial depolarization

PR interval shows

atrial contraction

QRS complex shows

ventricle depolarization and atria repolarization

ST interval shows

ventricle contraction

T wave shows

ventricle repolarization

QT interval shows

whole ventricular action potential

hypo or hyperkalemia manifests on ECG as

T wave changes, due to repolarization effect

Hypocalcemia manifests on ECG as

prolonged QT interval

hypercalcemia manifests on ECG as

shortened QT interval

increased sympathetic activity does what to automaticity and HR

increases automaticity, increased HR

increased parasympathetic activity does what to automaticity and HR

decreased automaticity and HR

What are the two mechanisms of automatic tachycardia?

increased slope of phase 4 OR decreased threshold of non SA nodal tissues

What are some causes of automatic tachycardia?

digitalis toxicity

hypokalemia

hypoxia

increased SNS or decreased PSNS

What phase is disrupted during early afterdepolarizations and why?

phase 3; due to Na channels opening

What phase is disrupted during delayed afterdepolarizations and why?

phase 4, Ca influx/release early

what are the two mechanisms/models of reentrant tachycardia?

anatomic and functional

What is the difference between A fib and atrial flutter?

a fib - faster HR, disorganized ECG, irregularly irregular pulse

a flutter - fast but slower HR, organized ECG, atrial to ventricular depolarizations occur in a pattern (1:1, 1:2, etc)

What is the major complication of a fib or a flutter?

embolic stroke due to blood stasis in atria

What are some causes of ventricular tachycardia?

ischemia

MI

metabolic abnormalities (hypokalemia)

hypoxemia

drugs (digitalis toxicity)

ventricular tachycardia is defined:

3 or more ventricular premature beats with rate >100bpm

What are the causes of chronic or reccurent ventricular tachycardia?

underlying heart diseases or left ventricular dysfunction and aneurism

What is the difference btw monomorphic and polymorphic ventricular tachycardia?

monomorphic - single foci, QRS similar beat to beat

polymorphic - multiple foci with varying QRS size and shape

Torsades de pointes is an example of what?

polymorphic ventricular tachycardia

Torsades de pointes is characterized by

long QT interval and QRS complexes undulating around a central axis

Which fibrillation is LIFE THREATENING and why?

V fib; blood is not filling or being pushed through the ventricles and there is no blood or oxygen getting to the rest of the body

What is a pro-arrhythmia?

a new or worsened arrhythmia due to antiarrhythmic drugs

what is an atrioventricular block?

a delay or interruption in the conduction from atria to ventricles

describe a first degree AV block

prolonged PR interval, but the impulse still reaches the ventricles

site of delay is the AVN

describe a second degree AV block

2 types:

Mobitz type I: progressive PR prolongation and QRS is sometimes dropped, usually due to AV nodal fatigue

Mobitz type II: no PR prolongation, dropped QRS, block is at the AVN or below

describe a third degree AV block

complete block, the atria and ventricles beat independently. ventricular escape rhythm is very slow