SVT MANAGEMENT GUIDELINE IN ADULTS

1. ACC/AHA GUIDELINE FOR
MANAGEMENT OF SVT IN
ADULT PATIENTS
DR MAHENDRA
CARDIOLOGY,JIPMER

2. SVT
• tachycardia's having atrial and/or ventricular rates in excess of 100 bpm at rest.
• mechanism of which involves tissue from the His bundle or above.
SVTs include-
• inappropriate sinus tachycardia
• AT (including focal and multifocal AT)
• macro reentrant AT
• junctional tachycardia
• AVNRT, and various forms of accessory pathway-mediated reentrant tachycardias.
• In this guideline, the term does not include AF.

3. • prevalence of SVT is 2.25 per 1,000 .
• incidence of PSVT is 36 per 100,000 persons per year.
• Women have twice the risk of men of developing PSVT .
• Individuals >65 years of age have >5 times the risk of younger persons of
developing PSVT.

4. Clinical History
• Modes of presentation-
• documented SVT in 38%
• palpitations in 22%
• chest pain in 5%
• syncope in 4%
• AF in 0.4%
• sudden cardiac death in 0.2%

11. Differential diagnosis with adenosine

14. • SPECIFIC TACHYARRHYTHMIAS

15. Sinus Tachyarrhythmias-
a. Physiological Sinus Tachycardia
b. Inappropriate Sinus Tachycardia
c. Sinus Node Re-Entry Tachycardia

16. Inappropriate Sinus Tachycardia
• persistent increase in resting heart rate unrelated to the level of physical, emotional,
pathological,or pharmacologic stress.
• 1. Enhanced automaticity of the sinus node
• 2. Abnormal autonomic regulation of the sinus node with excess sympathetic and reduced
parasympathetic tone.
• Diagnosis-
• presence of a persistent sinus tachycardia (heart rate more than 100 bpm) during the day with
excessive rate increase in response to activity and nocturnal normalization of rate as confirmed by
a 24-hour Holter recording.
• tachycardia (and symptoms) is nonparoxysmal.
• P-wave morphology and endocardial activation identical to sinus rhythm.
• Exclusion of a secondary systemic cause.

18. Sinus Node Re-Entry Tachycardia
• Diagnosis-
• tachycardia and symptoms are paroxysmal.
• microreentrant circuit
• P-wave is identical to sinus rhythm.
• distinguish sinus node reentry from sinus tachycardia are an abrupt onset and
termination
• often a longer RP interval than that observed during normal sinus rhythm.
• termination occurs with vagal maneuvers or adenosine.
• Induction of the arrhythmia is independent of atrial or AV-nodal conduction time.

19. • Treatment-
• no controlled trials of drug prophylaxis for pts with SNRT.
• respond to vagal maneuvers, adenosine, amiodarone, beta blockers,
nondihydropyridine calcium-channel blockers, or even digoxin.
• EP studies for frequent or poorly tolerated episodes of tachycardia that do not
adequately respond to drug therapy.
• Radiofrequency catheter ablation is generally successful.

20. AVNRT
• Presence of a narrow complex tachycardia with regular R-R
intervals and no visible p waves.
• P waves are retrograde and are inverted in leads II,III,avf.
• P waves are buried in the QRS complexes –simultaneous
activation of atria and ventricles – most common presentation
of AVNRT –66%.
• If not synchronous –pseudo s wave in inferior leads ,pseudo r’
wave in lead V1---30% cases .

24. Atypical AVNRT
• Arrows point to the P wave.
• The reentrant circuit involves anterograde conduction over a fast atrioventricular
node pathway, followed by retrograde conduction in a slow atrioventricular node
pathway, resulting in a retrograde P wave (negative polarity in inferior leads) with
long RP interval.

27. AVRT
• Typical – RP interval < PR interval
• RP interval > 80 milli sec
• Atypical –RP interval > PR interval
• Concealed bypass tract – only retrograde conduction
• Manifest bypass tract– both anterograde and retrograde.
• Electrical alternans –the amplitude of QRS complexes varies by 5 mm
alternatively.

31. Orthodromic Atrioventricular Reentrant
Tachycardia
• The reentrant circuit involves anterograde conduction over the
atrioventricular node, followed by retrograde conduction over an
accessory pathway, which results in a retrograde P wave with short RP
interval.

35. Junctional Tachycardia

36. • 1. Junctional Tachycardia-
• origin from the AV node or His bundle
• heart rates of 110 to 250 bpm and a narrow complex or typical BBB conduction
pattern
• Atrioventricular dissociation is often present
• arrhythmia is thought to be either abnormal automaticity or triggered activity.
• uncommon in adults
• typically seen in infants postoperatively, after cardiac surgery for congenital heart
disease.

38. • 2. Nonparoxysmal Junctional Tachycardia
• benign arrhythmia
• narrow complex tachycardia with rates of 70 to 120 bpm.
• enhanced automaticity arising from a high junctional focus or in response to a triggered mechanism
• cannot be terminated by pacing maneuvers.
• Cause-
• digitalis toxicity,
• postcardiac surgery
• hypokalemia,
• myocardial ischemia.
• chronic obstructive lung disease with hypoxia
• inflammatory myocarditis.

40. Focal AT and MAT

41. AT
• Rapid (usually <250 beats/ min), relatively regular rhythms that
originate in the atrial musculature.
• Mechanisms include abnormal automaticity and triggered activity.
• Foci are most frequently found in the pulmonary veins in the LA and
the crista terminalis in the right atrium.
• Myocardial infarction, nonischemic heart disease,obstructive lung
disease, serum electrolyte disorders, and drug toxicity

42. • RP intervals can be variable
• RP often > PR
• (Example slower than more common rate
150-250 beats per min)
Atrial
Tachycardia
V1
Differs from
AV nodal or
AV reentrant
SVT

45. MAT
• rapid, irregular rhythm with at least 3 distinct morphologies of P waves on the
surface ECG
• distinct isoelectric period between P waves.
• The P-P, PR, and R-R intervals are variable.
• associated with pulmonary disease, pulmonary hypertension, coronary disease,
and valvular heart disease , hypomagnesemia and theophylline therapy.
• first-line treatment is management of the underlying condition

46. Multifocal Atrial Tachycardia
ECG Characteristics: Discrete P waves with at least 3different
morphologies.
Absence of one dominant atrial
pacemaker
Atrial rate > 100 bpm.
The PP, PR, and RR intervals all vary.

48. Atrial Flutter
• Usually a single, irritable foci in the atria (right)
• AV node protects the ventricles by blocking some of the atrial
impulses (decremental conduction)
• P waves take on a “sawtooth” appearance and are called F waves or
flutter waves
• Atrial rhythm and ventricular response are usually regular
• Atrial rate 250-350 beats/min. Ventricular rate varies depending
on the number of impulses the AV node is blocking
• No P waves or PR interval
• QRS normal width or with aberrancy

53. Special population
• ADULT ACHD
• PREGNANCY
• OLDER POPULATION

54. ACHD
• SVT is observed in 10% to 20% of ACHD .
• increased risk of heart failure, stroke, and SCD.
• mechanism of SVT in ACHD patients is macro reentrant AT, which accounts for at
least 75% of SVT

60. THANK YOU