Av Nodal Blocks

AV Nodal blocks

Differentiating between first, second, and third-degree atrioventricular node blockages “The end of a bad relationship”

Electrical Conduction of the Heart

Normal Sinus Rhythm

What is an AV Heart Block?  Signal

from the SA node to the AV node is impaired or doesn't transmit.  Blood is still flowing through the heart chambers.

Signs & Symptoms  Slow

heartbeat  Irregular heartbeat  Breathlessness with exertion  Breathlessness caused by fever  Dizziness  Weakness  Fainting  Fatigue

First Degree AV Block

üDelayed conduction through AV node üProlongation of PR interval

Second Degree (Type I) AV Block

üProgressive lengthening of PR interval until a QRS is not conducted (ventricular contraction does not occur)

Second Degree (Type II) Mobitz AV Block

üConstant PR interval before a skipped ventricular conduction

Third Degree (Complete) AV Block

üComplete dissociation of atrial and ventricular conduction üP wave and PR interval normal üJunctional pacemaker – narrow QRS üVentricular pacemaker – wide QRS üRate 30 – 50 beats/min

Demographic predisposition  More

common in males than females in a 1:4 ratio  Prevalence increases with age with individuals >65 comprising the majority of cases.  Typical heart-affecting lifestyles increase the risk exponentially (Dr.Ugs, smoking, etc.)

Field differentiation

Field Treatment Protocols  With

all cases of chest pain assume (potential) life threats.  ABC’s  Initiate cardiac monitor  Perform minimal secondary survey › Neck: assess for JVD/tracheal position › Chest: inspect, auscultate › Extremities: skin colour, condition,

peripheral edema, distal pulses › Vital signs

Management Enroute  Manage

survey problems  High concentration O2  Transport patient (semi)sitting  Advise Pt. to rest quietly  Administer appropriate SR meds  Re-evaluate enroute at 5-minute intervals.  Typically CODE 4, C.T.A.S. 2 or 1 if patient is coding