Calculating the rate :
Lead II: rhythm strip , shows the rhythm for the whole time RCG is recorded .
Identify the squares between the R-R interval . (normal rhythm )
Rate :
300/ the number of the big squares .
1500/ the number of the small squares .
If the rhythm is irregular :
Rate : number of waves in a 6 second strip x 10
Each large square =0.2 second , 6/0.2 : 30
Cardiac arrhythmia definition:
Group of conditions in which the electrical activity of the heart is faster or slower
than normal .
Classification :
Normal sinus rhythm (NSR) Various cardiac arrhythmias
a. Atrial premature contraction
(APC)/PAC
b. Atrial flutter
c. Atrial fibrillation
d. Supraventricular tachycardia
(SVT)
e. Premature ventricular
contraction(PVC)
f. Ventricular tachycardia (VT)
g. Ventricular fibrillation (VF)
Sinus Arrhythmia :
Normal physiological phenomenon , the heart rate varies due to reflex changes in
vagal tone during different stages of respiratory cycles.
Inspiration increases the heart rate via the decrease of vagal tone .
Expiration decreases the heart rate via the restoration of vagal tone .
PAC/APC/APB
: P-small or inverted (abnormal shape)
:PR interval-short (followed by a wide pause)
PP interval-irregular
Atrial Flutter :
: rapid regular contraction
Rate: 250~400
Saw tooth appearance (normal P is replace by F wave , absent P wave)
PR regular (maybe irregular when there is variable block)
Atrial fibrillation :
: P wave is absent (may be replaced by fibrillatory F wave)
: Rhythm : irregularly regular
:”sagging” ST segment depression is visible in V6,II,III, and aVF suggestive
digoxin effect .
Etiology : DM, HTN , Hyperthyroidism , mitral valve disease , idiopathic (less
atrial fibrillation)
Treatment :
1. Beta blocker , bisoprolol , metoprolol.
2.calcium channel blocker (non-dihydropyridine calcium channel blocker )
3.digoxin
4.amiodarone (long term side effect : hypothyroidism)
- rhythm control : Defibrillation (min: 50 joules)
- treatment of the cause: HTN, IHD,hyperthyroidism.
AF with rapid ventricular response :
P wave absent.
Irregularly irregular fast ventricular response .
Heart rate 150 bpm.
Supraventricular tachycardia (SVT )
: narrow complex tachycardia at 215 bpm
: No visible P waves
: Retrograde P waves (upright in V1 , inverted in lead II)
Beat to bear variation in QRS amplitude without evidence of low voltage (QRS
alternans)
Rhythm regular .
Premature ventricular contractions (PVC)
:Heart beat initiated by purkinje fibers in the ventricles rather than by Sinoatrial
nodes (SA nodes) in a normal heartbeat initiator.
: absent P wave
: QRS wide>0.12 second (3 small squares )
: T wave opposite to major deflection (R wave )
: often occurs in repeating patterns .
Bigeminy : every second beat is PVC
Trigeminy : every third beat is PVC
Quadrigeminy : every fourth beat is PVC
Couplet : two consecutive PVCs
Triplet : three consecutive PVCs
Ventricular Tachycardia (VT)
Broad complex tachycardia originating in the ventricles . Although a few seconds
may not result in the ventricles. Short periods may occur without symptoms or
present with :
Lightheadedness , palpitations or chest pain.
Ventricular tachycardia may result in cardiac arrest and turn into ventricular
fibrillation.
: P wave -absent
: QRS-Broad >0.12 second ,abnormal or bizarre pattern
: Rate > 100 beats/minutes (usually 140-220 beats/minutes)
Non sustained VT : ECG
: Runs of VT
: Very broad QRS
: P wave absent
Ventricular Fibrillation :
Ventricular fibrillation is life threatening , and the most serious cardiac rhythm
disturbance.
Lower chambers quiver and the heart can’t pump any blood , causing cardiac
arrest.
: chaotic irregular deflections of varying amplitude ,
: No identifiable P waves , QRS complexes, or T waves .
: rate 150 to 500 bpm
: amplitude decreases with duration
