ECG: Conduction Block
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Transcript of ECG: Conduction Block
ECG OF THE WEEK
PROF.VIJAYARAGHAVAN’S UNITM 7
BHARGAVI.K
HISTORY IN BRIEF 27 YR OLD FEMALE P2L2A2 WITH C/O
BREATHLESSNESS AT REST ON/OFF FOR 1 MONTH.
C/O SWELLING OF LEGS FOR 20 DAYS. COUGH WITH EXPECTORATION FOR
15 DAYS. CONDITION: PALLOR, BPPE+,B/L
CREPTS+, SM + TA.
INTERPRETATION 12 leaded ecg showing a complete heart
block-AV DISSOCIATION Atrial rate-100:ventricular rate:67-68/min RAD PR INTERVAL CANNOT BE COMMENTED QRS-BROAD N WIDE RBBB LIKE,ST DEPRESSION N T INVERSION
V1-V4.
Rhythms Produced by Conduction Block
AV Block (relatively common) 1st degree AV block Type 1 2nd degree AV block Type 2 2nd degree AV block 3rd degree AV block
SA Block (relatively rare)
Causes Ischemic heart disease, cardiomyopathy and
degenerative changes Drugs that depress AV conduction,DIGITALIS
TOXICITY Myocardial infarction, infiltration (e.g., tumor) Trauma (e.g., surgery; therapeutic ablation) Lev disease: fibro calciferous involving aortic valve
extending to conducting sys Lenegres disease: sclero degenarative process
involving conducting system CHAGAS DISEASE Congenital abnormalities
Congenital Acquired ISOLATED HEREDITARY CONNECTIVE TISSUE QRS 40-50 bpm QRS DURATION
NORMAL RATE ^WITH
ATROPINE PROXIMAL BLOCK PACE MAKER
MANDATORY
IWMI/AWMI LEVE’S LENEGRE QRS 20-30bpm PROLONGED NOT SO
DISTAL NOT SO
FIRST-DEGREE HEART BLOCK OCCURS WHEN THERE IS A PARTIAL
INTERRUPTION ANYWHERE IN THE ATRIAL OR AV JUNCTIONAL CONDUCTION SYSTEM.
THE IMPULSE IS EVENTUALLY CONDUCTED BUT IS DELAYED.
EKG Characteristics: Prolongation of the PR interval, which is constant
All P waves are conducted
MOBITZ I HEART BLOCK MOBITZ I ( WENCKEBACH OR SECOND-DEGREE
HEART BLOCK, TYPE I). PROGRESSIVE BLOCK. IMPULSE FROM THE ATRIA IS INTERRUPTED AT THE AV
JUNCTION. (1)The P-R interval becomes longer and longer
(2)The R-R interval gets shorter and shorter. THE INTERRUPTION BECOMES LONGER WITH EACH
IMPULSE DELAYING DEPOLARIZATION OF THE VENTRICLES UNTIL A COMPLETE INTERRUPTION BLOCKS THE IMPULSE.
II
Block
P P P PP
Second Degree AV Block - Type I(Wenkebach or Mobitz I Block)
MOBITZ II HEART BLOCK
OCCURS DUE TO AN INTERMITTENT INTERRUPTION NEAR OR BELOW THE AV JUNCTION.
INTERRUPTION IS NOT PROGRESSIVE, BUT OCCURS SUDDENLY
P WAVES BEFORE EVERY QRS COMPLEX AND ALL ARE THE SAME SIZE AND SHAPE.
Second Degree AV Block - Type II
P P P P P
Block
THIRD-DEGREE HEART BLOCK COMPLETE HEART BLOCK OR COMPLETE AV
DISSOCIATION. IMPULSE IS COMPLETELY BLOCKED BETWEEN THE
ATRIA AND THE VENTRICLES. USUALLY TAKES PLACE BETWEEN THE AV JUNCTION
AND BUNDLE OF HIS. 1).The atrial and the ventricular rhythms are
absolutely independent of one another .
2).There is no P-R to QRS relationship.3).The atrial rate is more rapid than the ventricular rate.4).regular P-P interval .5).rugular R-R interval
3rd Degree (Complete) AV Block
EKG Characteristics: No relationship between P waves and QRS complexes
Relatively constant PP intervals and RR intervals
Greater number of P waves than QRS complexes
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MANAGEMENT 1ST DEGREE BLOCK – ASSESS AND MONITOR THE
PATIENT. MOBITZ I ( 2ND DEGREE, TYPE I) – USUALLY DOES NOT
REQUIRE TREATMENT, BUT IF THE PATIENT IS MEDICALLY UNSTABLE OR POOR CARDIAC OUTPUT ATROPINE IS USED IF THE OVERALL RATE IS BRADYCARDIC.
MOBITZ II (2ND DEGREE, TYPE II) – OXYGEN, IV FLUIDS,ATROPINE IF OVERALL RATE IS BRADYCARDIC, ARTIFICIALPACEMAKER, DOPAMINE OR EPINEPHRINE.
IF HEART RATE IS GREATER THAN 100 BUT LESS THAN 150 DILTIAZEM, DIGOXIN, OR BETA BLOCKERS. 3RD DEGREE BLOCK – OXYGEN, IV FLUIDS, ATROPINE
IFBRADYCARDIC, DOPAMINE, EPINEPHRINE, OR ARTIFICIALPACEMAKER.