DR.SENTHAMIZHSELVAN. K

PROF.DR.RAMASAMY’S UNIT

ECG OF THE WEEK

CLINICAL PICTURE

14 year old girl presented to opd with H/O giddiness and transient LOC for few secs followed by spontaneous recovery No H/O chest pain ,palpitation, breathlessness, head ache No H/O drug intake H/O 3 similar episodes over the past 6 months Not a k/c of heart disease O/E Pulse was 52/min ,irregular

BP 110/70 mmHg CVS,RS,CNS –NAD

ecg

FINDINGS

Rate :45/min axis :+110 p wave morphology and duration - normal Alternate P waves are not conducted PR interval =0.16 s ,RR interval and PP

interval are regular and constant QRS duration 0.10s , QTc interval =0.60sBizarre T wave inversion in V3-V6,L2,L3,aVF

IMPRESSION

A case of 2:1 AV block, with bizarre and giant T wave inversion ,QTc prolongation

Level of the block to be confirmed by HIS –BUNDLE electrogram

Recurrent syncopal attacks can be attributed to

STOKES-ADAMS-ATTACKS

ATRIO-VENTRICULAR BLOCK

Atrial conduction to ventricle is blocked at a time when AV

junction is not physiologically refractory;

Normal AV nodal delay is 0.1 sec.;

Fast SV rhythm like AF,AFL,has a barrier at AV node to reduce ventricular rate ;

Block occurs at AV node or HIS Purkinje system to be confirmed by HIS electrogram;

HIS BUNDLE ELECTROGRAM

PA 20-50 msec; AH 50-140 msecHV 35-55 msec;

CLASSIFICATION

INCOMPLETE - 1st degree;2nd degree; COMPLETE - 3rd degree; FIRST DEGREE AV BLOCK - Prolongation of PR interval beyond 0.2

secs(adults),0.18secs(children);

- No change in underlying rhythm;

- If QRS normal – block in AV node 87% cases, prolonged AH interval;

- If QRS abnormal – block in infranodal region, prolonged HV interval

SECOND DEGREE AV BLOCK

Some sinus impulses are conducted to ventricles &

some are not; MOBITZ TYPE I BLOCK(WENCKEBACH) -progressive prolongation of PR interval prior to

non conducted P waves; - PR interval prolongation is in decreasing

increments; - progressive shortening of RR interval; - the pause comprising the blocked P wave is <

the sum of two P-P intervals - this pattern occurs regularly –’group beating’

CONDUCTION RATIO /WENCKEBACH PERIOD

- Ratio of number of P waves to number of QRS in a sequence ;

- Normal QRS- block almost always in AV node;

- QRS abnormal- block in infranodal pathways;

MOBITZ TYPE II BLOCK

Constant PR,PP interval; No wenckebach phenomenon; Fixed block, QRS abnormality present; Pause including blocked P wave = 2× PP interval; Mostly infranodal block; 2:1 AV BLOCK MT1 MT2 - carotid sinus massage - no

change,fixed atropine,exercise can unmask it 2:1 block (2:1 -3:2) -HIS electrogram- nodal - infra nodal

COMPLETE AV BLOCK

Third degree block;

Failure of all P waves to reach the ventricles

Two independent pacemakers one in atria,other in ventricles

function in asynchronous manner • Block at AV node-escape rhythm is junctional (40- 60/mt)narrowQRS

• Block at HIS system –escape rhythm is ventricular (20-

40/mt)wide QRS

STOKE-ADAMS ATTACKS

Morgagni synd. @ Spens synd. @ Stokes synd.

sudden transient syncope ,due to cardiac dysrhythmia;

occasional seizures; respiration is normal throughout -hence on recovery ,pt. appears flushed; -posture independent; -multiple attacks per day; -asystole/VF/CHB/--- possible triggers Treatment;--Drugs – DDI pacing

CAUSES OF AV BLOCKS

REVERSIBLE PERMANENT

PHYSIOLOGIC; CAD; CAD; MATERNAL

SLE; INF. ENDOCARDITIS; CMP; MYOCARDITIS; INFILTRATIVE; METABOLIC; TRAUMATIC; TRAUMATIC; TUMOURS; DRUG INDUCED; NM

DISORDERS; IDIOPATHIC;

MANAGEMENT

Identify transient causes and treat; PERMANENT PACING IF - symptomatic +advanced block; -asymptomatic +complete heart block / infranodal second deg.

block• TEMPORARY /PROPHYLACTIC PACING IF -block with hemodynamic compromise -AMI with development of new blocks ----permanent pacing to be considered later

Thank u