Ventricular, Conduction Delay, and Misc Rhythms

How do ventricular premature complexes appear?

Have a QRS that is wider and much different appearance than the sinus complexes

T wave opposite polarity to QRS

What is bigeminy in terms of VPCs?

Alternating sinus and VPC beats

4+ VPCs and a HR of > 180 bpm =

Ventricular tachycardia

VPCs originating in the RV

Depolarizes along lead II leading to a positive wave

VPCs originating in the LV

Depolarizes away from lead II leading to a negative wave

5 main groups of etiologies that can cause ventricular arrhythmias

- primary cardiac disease

- metabolic/endocrine disorders

- drugs and toxins

- autonomic imbalance

- general/common disease states

What electrolytes can result in arrhythmias?

K+, Ca2+, Mg2+

What drugs and toxins can result in arrhythmias?

- digoxin

- amphetamine

- theobromine

What sorts of diseases/disease states can cause arrhythmias?

- GDV

- sepsis

- splenic disease

- hypoxia

- hypovolemia

- pain

- trauma

What autonomic imbalance can result in arrhythmias?

Increased sympathetic tone

What are accelerated idioventricular rhythms?

- slow v tach

- multiple ventricular beats in a row that are happening slow

- warrants workup but not hemodynamically compromising, usually don't have to treat

Therapy for single VPCs and AIVR

- address underlying disease

- specific therapy only needed if patient is hemodynamically affected

- lidocaine or procainamine

Characteristics of sustained v tach

- hemodynamically devastating rhythm

- potential for rapid decompensation and development of v fib

In what conditions may we see sustained v tach?

- boxers with ARVC

- dobermans with DCM

- myocarditis (Chugs disease)

Therapy for sustained v tach

- lidocaine

- procainamide

Hemodynamic consequences of arrhythmias

- decreased cardiac function

- drop in BP

- reduced tissue perfusion

- limited exercise capacity

- syncope

Electrical instability can result in...

- myocardial fibrillation

- asystole

- sudden cardiac death

Treatment of v fib

- CPR

- electrical defibrillation

- magnesium

Home therapy for ventricular arrhythmias

- sotalol

- procainamide

- amiodarone

- mexiletine