Prof.P.Vijayaragavan unit.Prof.P.Vijayaragavan unit.Dr.Vijayalakshmi.M7unit.Dr.Vijayalakshmi.M7unit.

Rate: 180/min.Rate: 180/min.

Rhythm: Narrow complex Rhythm: Narrow complex supraventricular tachycardia.supraventricular tachycardia.

Axis:LAD -80 degree.Axis:LAD -80 degree.

PR interval not determined.PR interval not determined.

QRS:80msec.QRS:80msec.

Diagnosis:Narrow QRS complex Diagnosis:Narrow QRS complex tachycardiatachycardia..

• Tachycardia,Pseudo “r” wave Tachycardia,Pseudo “r” wave (hidden “P”) seen in lead V1.(hidden “P”) seen in lead V1.

• RP interval 60 msec.RP interval 60 msec.• PR interval 280msec.PR interval 280msec.• Short RP interval,Long PR interval Short RP interval,Long PR interval

AV NODAL REENTERANT AV NODAL REENTERANT TACHYCARDIATACHYCARDIA..

• The QRS complex is normal in contour The QRS complex is normal in contour and duration . Often the P wave is and duration . Often the P wave is buried in the QRS or seen just after the buried in the QRS or seen just after the end of the QRS and causes subtle end of the QRS and causes subtle alteration in the QRS complex that alteration in the QRS complex that results in a pseudo ‘s’ or pseudo ‘r’ which results in a pseudo ‘s’ or pseudo ‘r’ which may be recognized only in comparison to may be recognized only in comparison to the QRS complex in normal rhythm. the QRS complex in normal rhythm. Cycle length and or QRS alternans can Cycle length and or QRS alternans can occur usually when the rate is very fast.occur usually when the rate is very fast.

AVNRT- most common type of reentrant tachycardia.AVNRT- most common type of reentrant tachycardia.

Common in females.Common in females.

Occurs in 3Occurs in 3rdrd or 4 or 4thth decade. decade.

Types ;Types ;

1)Typical-slow –fast pathway (alpha pathway) 95%1)Typical-slow –fast pathway (alpha pathway) 95%

2)Atypical AVNRT-fast-slow pathway .5%.2)Atypical AVNRT-fast-slow pathway .5%.

3)Slow-slow pathway. 2%.3)Slow-slow pathway. 2%.

4)Slow –accessory pathway, rare.4)Slow –accessory pathway, rare.

• Slow or alpha pathway has short Slow or alpha pathway has short refractory period and slow refractory period and slow conduction.conduction.

• Fast pathway has fast conduction and Fast pathway has fast conduction and long refractory period.long refractory period.

• Re-entry occurs when there are two Re-entry occurs when there are two pathways with different conduction pathways with different conduction properties and there should be properties and there should be unidirectional block.unidirectional block.

• The mechanism of PSVT is classified on the The mechanism of PSVT is classified on the basis of R-P interval.basis of R-P interval.

• Short RP interval tachycardia-Short RP interval tachycardia-• RP interval is <50% of RR interval.RP interval is <50% of RR interval.• 1)AVNRT typical.1)AVNRT typical.• 2)Orthodromic AV reentrant tachycardia (o-2)Orthodromic AV reentrant tachycardia (o-

AVRT)AVRT)• Sinus tachycardia or ectopic atrial Sinus tachycardia or ectopic atrial

tachycardia with first degree AV block.tachycardia with first degree AV block.• 4)Junctional tachycardia.4)Junctional tachycardia.

• Long RP interval tachycardia.Long RP interval tachycardia.• RP interval is > 50% of RR interval.RP interval is > 50% of RR interval.• 1)Sinus tachycardia or ectopic atrial 1)Sinus tachycardia or ectopic atrial

tachycardia with normal PR interval.tachycardia with normal PR interval.• 2)Atypical AVNRT. 2)Atypical AVNRT. • 3)O-AVRT3)O-AVRT..

AVNRTAVNRT1.Most common.1.Most common.2.Common in females.2.Common in females.3.Micro reentry.3.Micro reentry.4.slow-fast pathway.4.slow-fast pathway.5.Initiated by APC 5.Initiated by APC

with prolonged PR with prolonged PR interval.interval.

6.Simultaneous 6.Simultaneous activation of atrium activation of atrium and ventricles.and ventricles.

• AVRTAVRT• 1.Less common.1.Less common.• 2.Common in males.2.Common in males.• 3.Macro reentry.3.Macro reentry.• 4.AV node Accessory 4.AV node Accessory

pathwaypathway• 5.Initiated by APC 5.Initiated by APC

with short or normal with short or normal PR interval.PR interval.

• 6.Sequential 6.Sequential activation of atrium activation of atrium and ventricles.and ventricles.

• AVNRTAVNRT• 7.Rate <200/min.7.Rate <200/min.• 8.P usually buried in 8.P usually buried in

QRS complexes.QRS complexes.• 9.Pseudo ‘r’ pseudo 9.Pseudo ‘r’ pseudo

‘s’ seen, and pseudo ‘s’ seen, and pseudo RBB pattern seen.RBB pattern seen.

• 10.RP-interval is 10.RP-interval is <70msec.<70msec.

• 11.QRS alternans 11.QRS alternans rare.rare.

• AVRTAVRT• 7.Rate >200/min.7.Rate >200/min.• 8.P wave usually seen 8.P wave usually seen

after QRS complexes.after QRS complexes.• 9.Not seen.9.Not seen.

• 10.RP interval 10.RP interval >70msec.>70msec.

• 11.QRS alternans 11.QRS alternans common.common.

• AVNRTAVNRT• 12.Aberrancy rare.12.Aberrancy rare.• 13.BBB does not 13.BBB does not

alters the rate.alters the rate.• 14.Ventricles not 14.Ventricles not

required for required for reentry.reentry.

• 15.It is possible in 15.It is possible in the presence of AV the presence of AV block also.block also.

• AVRTAVRT• 12.Aberrancy 12.Aberrancy

common.common.• 13. BBB alters the 13. BBB alters the

rate.rate.• 14. Ventricles 14. Ventricles

required for reentry.required for reentry.• 15.Not possible in 15.Not possible in

the presence of AV the presence of AV block. (not block. (not continuous)continuous)

• Clinical features-Clinical features-• AV nodal re entry commonly occurs in AV nodal re entry commonly occurs in

patients who have no structural heart patients who have no structural heart disease and in the adults of 3disease and in the adults of 3rdrd or 4 or 4thth decade.decade.

• Palpitation, nervousness, anxiety to Palpitation, nervousness, anxiety to angina, heart failure, syncope or shock.angina, heart failure, syncope or shock.

• The prognosis for the patients without The prognosis for the patients without heart disease is good.heart disease is good.

TREATMENTTREATMENT

• Sedation, Reassurance, Vagal Sedation, Reassurance, Vagal maneuvers.maneuvers.

• 1.Carotid sinus massage.1.Carotid sinus massage.• 2.Gag reflex.2.Gag reflex.• 3.Immersion of face into chilled water. 3.Immersion of face into chilled water.

(children)(children)• 4.Coughing.4.Coughing.• 5.Recumbent position with leg elevation.5.Recumbent position with leg elevation.• 6.Valsalva maneuver.6.Valsalva maneuver.• 7.Muller maneuver.7.Muller maneuver.

• Drugs-Adenosine 6 mg initially then Drugs-Adenosine 6 mg initially then 12mg followed by 12 mg. IV-rapidly 12mg followed by 12 mg. IV-rapidly given.90 percent gets success.given.90 percent gets success.

• Verapamil 5-10 mg IV. Or Verapamil 5-10 mg IV. Or diltiazem0.25 to 0.35mg per kg. in diltiazem0.25 to 0.35mg per kg. in two minutes given ,success 90 two minutes given ,success 90 percent.percent.

• Digitalis –slow onset of action and Digitalis –slow onset of action and has longer effect.0.5mg every 2-has longer effect.0.5mg every 2-4hrs. Total dose< 1.5mg per 24 hrs. 4hrs. Total dose< 1.5mg per 24 hrs. B-Blockers may be givenB-Blockers may be given..

• If cardiac decompensation occurs consider If cardiac decompensation occurs consider DC shock. Energy 10 to 50 J.DC shock. Energy 10 to 50 J.

• Overdrive pacing may be useful .Overdrive pacing may be useful .

• For recurrence;For recurrence; Calcium channel antagonist, B- Calcium channel antagonist, B-Blockers, Digitalis.Blockers, Digitalis.

Radiofrequency AblationRadiofrequency Ablation; ; More than 95% effective .Complete More than 95% effective .Complete cure is possible, Long term effect. And has cure is possible, Long term effect. And has low incidence of complications.low incidence of complications.