ecg - av block
TRANSCRIPT
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