It is very important for diagnosis and treatment of arrhythmia

1. APPROACH TO NARROW QRS
COMPLEX TACHYCARDIA
Dr. Faqirullah Faiq, IM resident year 3
Jan 25, 2024

2. AGENDA
• Important Definitions
• Differential diagnosis & classifications
• Epidemiology of Narrow complex SVT
• Specific arrhythmias with diagnostic ECGs
• Clinical presentation
• Initial evaluation
• Acute management
• Long-term management

3. DEFINITION
• HR> 100 beats/min
• Narrow QRS
• QRS duration < 120 msec
• Origin: above or within
AV node (uptodate says
above or within His
bundle)
• Wide QRS
• QRS duration > 120 msec
(3 small squares)
• Abnormally slow
• VT
• Aberrant conduction
• Accessory pathway

5. EPIDEMIOLOGY
• It's a common tachycardia
• SVT: prevalence is 2.25/1000 persons incidence is 35/100.000 person-years
• Women have a greater risk of developing SVT (2 times)
• older age (>65 yrs) are higher risk of SVT (5 times)
• In cath. Lab the most commonly treated is AF & AVNRT followed by A. flutter &
AVRT

6. DIFFERENTIAL DIAGNOSIS &
CLASSIFICATIONS

7. ATRIAL ARRHYTHMIAS

8. SINUS TACHYCARDIA
• Appropriate:
• Physiological causesanything that stimulates: the sympathetic nervous system
• anxiety, pain, fear, fever or exercise
• Always consider the following causes as well:
• Drugs, e.g. adrenaline, atropine, salbutamol (do not forget inhalers and
nebulizers), caffeine and alcohol
• Ischemic heart disease and acute myocardial infarction
• Heart failure
• Pulmonary embolism
• Fluid loss
• Anemia
• Hyperthyroidism

9. SINUS TACHYCARDIA
• Inappropriate
• Fast sinus rate > 100 bpm at rest or minimal activity
• Out of proportion of physiological, pathological or pharmacological stress
• Persistent
• Young females
• Mechanism: poorly understood (dysautonomia, neurohormonal
dysregulation, intrinsic SAN hyperactivity)
• Warm up/ warm down

10. INAPPROPRIATE SINUS
TACHYCARDIA
• ECG morphology:
• Sinus tachycardia
• 24 hr Holter monitroing:
• Mean HR > 90 bpm
• exaggerated HR
• response >100 b.p.m.
during waking hrs
• Ddx
• Appropriate Sinus tachy.
• Sinus node reentry

11. FOCAL ATRIAL TACHYCARDIA
• Definition:
• organized atrial rhythm >100 bpm initiated from a discrete
FOCUS and spreading over both atria in a centrifugal pattern.
• Mechanism: enhanced automaticity or triggered activity
• Prevalence: 0.34% -0.4%
• May be incessant
... TICM

12. • ECG criteria:
• Regular atrial rate: 100 bpm- 250 bpm
• Discrete monomorphic abnormal P waves, different from sinus P waves
• Stable CL
• 1:1 AV conduction producing regular HR or variable AV conduction depending on
atrial rate or use of AADs
• A negative P wave in lead I & aVL suggests LA origin

13. ATRIAL FIBRILLATION
• common and important arrhythmia, affecting 1.5%–2% of people in the developed
world
• is associated with an increased risk of stroke and heart failure.
• The basis of AF is rapid, chaotic depolarization occurring throughout the atria as a
consequence of multiple ‘wavelets’ of activation.
• No P waves are seen and the ECG baseline consists of low-amplitude oscillations
(fibrillation or ‘f’ waves).
• Although 400–600 impulses reach the AV node every minute, only some will be
transmitted to the ventricles

15. ATRIAL FLUTTER
• Macro-reentrant atrial arrhythmia
characterized by continuous regular
electrical activity
• Prevalence: 88/100.000 person-
years
• Re-entry in RA: most commonly
CTI- dependent A. flutter
• Re-entry in LA: Rare
• Usually SHD or pulmonary dis. Or
post op cardiac or pulm.
• ECG criteria:
• Regular atrial rate: 250-330
bpm
• uniform flutter waves with
characteristic saw-tooth
appearance
• Vent. Rate: 1:1, 2:1, 3:1 or
variable AV conduction

16. ATRIAL FLUTTER

18. MULTI-FOCAL ATRIAL TACHYCARDIA
• characterized by a rhythm with at least three distinct P-wave morphologies
• rates typically between 100 and 150 beats/min.
• Unlike atrial fibrillation, there are clear isoelectric intervals between P waves and the
atrial rate is slower.
• Mechanism is likely triggered automaticity from multiple atrial foci
•

19. MAT

20. AV JUNCTIONAL ARRHYTHMIAS

21. ATRIOVENTRICULAR NODAL
REENTRANT TACHYCARDIA (AVNRT)
• Most common form of PSVT
• Microre-entry within the AV
Node
• Presentation is either early in
life or very later in life
• No SHD
• More common in women

22. TYPICAL AVNRT (SLOW-FAST)
• ECG diagnosis
• Narrow complex SVT unless
• Very regular, HR 150-250 bpm
• Very short RP interval
• Visible retrograde Pas an R' in lead V1 & aVR or psuedo-S wave in inferior leads in 1/3
of cases.
• No visible p waves, buried in ORS in other 2/3 cases
• " short RP tachycardia"

24. AVNRT (FAST-SLOW)
• Narrow complex SVT
• Less common (10%)
• Regular
• Long RP interval > PR interval
• "Long RP tachycardia"

26. AVRT

28. ORTHODROMIC TACHYCARDIA
(ORT)
• WPW - syndrome
• Short PR (<120 ms)
• Wide QRS (> 120 ms)
• Slur on upstroke or downstroke of QRS
(delta wave)

29. WPW SYNDROME

30. ORT
• Macro-reentrant tachycardia
• > 90% of AVRT
• 20-30% of all sustained SVTs
• HR 150- rarely, > 220 bpm
• ECG diagnosis
• Narrow complex SVT
• Regular
• Constant short RP interval
• ST-segment depression
"short RP tachycardia"

31. JUNCTIONAL ECTOPIC
TACHYCARDIA (JET)
• uncommon arrhythmia
• Abnormal automaticity at the
AVN or proximal His bundle
• Can be seen as congenital arrhtymias
• ECG diagnosis
• narrow QRS tachycardia
• short RP interval
• or AV dissociation

33. CLINICAL FINDINGS: SYMPTOMS
• Palpitations
• Chest pain
• Shortness of breath
• Syncope or pre-syncope
• Sudden cardiac arrest
• Patients are truly asymptomatic; this may be more common in
non-paroxysmal (incessant) tachycardias

34. CLINICAL FEATURES: SIGNS
• Tachycardia
• Hypotension
• Hypoxia and lung crackles

35. HEMODYNAMIC UNSTABLE
• Hypotension
• AMS
• Signs of Shock
• Ischemic chest discomfort and pain
• Acute heart failure

36. INITIAL EVALUATION
• Standard tests:
• History, physical examination, and 12 lead ECG
• Full blood counts, biochemistry profile, and thyroid
function
• An ECG during tachycardia should be sought
• Transthoracic echocardiography

37. • Optional
• Exercise tolerance testing
• 24h ECG monitoring, transtelephonic monitoring, or an implantable loop
recorder
• Myocardial ischaemia testing in patients with risk factors for coronary
artery disease (including men aged >40 years and post-menopausal
women)
• An EPS should be considered for a definitive diagnosis and when
catheter ablation is anticipated

39. ECG DURING
TACHYCARDIA
EVALUATION

40. DIAGNOSTIC VALUE OF IV
ADENOSINE

43. ACUTE MANAGEMENT IN THE ABSENCE
OF ESTABLISHED DIAGNOSIS !!

44. REGULAR
TACHYCARDIAS
• Irregular narrow complex SVT :
• Should be considered & treated as AF
• Rate control using CCBs or
BBs
• Electrical or
• pharmacological CV once
thromboprophylaxis is in place

45. TREATMENT OF SPECIFIC ARRHYTHMIAS
"ESTABLISHED DIAGNOSIS"

46. • Cath. Ablation :
• Is only considered in SAN re-entry in
case of failure of drug therapy.....
Favorable results
• Of no value in treatment of
IAS
.....Disappointing
results
• SINUS TACHYCARDIA (APPROPRIATE /
INAPPROPRIATE)

47. FOCAL ATRIAL
TACHYCARDIA
• Acute Managment

48. FOCAL ATRIAL
TACHYCARDIA
• Long term treatment
• cath. Ablation:
• Treatment of choice esp. in recurrent,
incessant FAT with TICM
• Esp. that AADs long-term success
rates are not favorable
• Amiodarone: young, pediatric pts, LV
dysfunc.
• Long-term efficacy is limited by Its side
effects

49. FOCAL ATRIAL TACHYCARDIA
• Cath. Ablation:
• Success rate 75-100%
• Complication rate 1.4%

50. ATRIAL
FLUTTER
• Acute treatment

51. ATRIAL FLUTTER
• Chronic therapy:
• Cath. Ablation is the most effective therapy
to maintain sinus rhythms
• Dofetilide, sotalol can be used to maintain
SR but concerns about proarrhythmia
• Anticaogulation:
• The thrombo-embolic risk of A. flutter,
although lower than that of AF is still
significant.
• • A.flutter + AF....
• Anticoag.

52. CTI DEPENDENT A.FLUTTER
ABLATION
• Success rate 95%
• Recurrence rate<10%

53. AVNRT
• Acute management

54. CHRONIC THERAPY AVNRT

55. AVNRT
• Cath ablation
• Slow pathway ablation
• Success rate 97%
• Recurrence rate 1.3-4%
• AV block <1% ... less incidence with cryoablation

56. AVRT
• Acute Management

57. AVRT
• Cath. Ablation
• Acute success rate 95%
• complication rate 1.5%
• Complete AV block 0.17-2.7% ....
Cryo-ablation for septal AP

58. TAKE HOME MESSAGE
• SVT is one of the commonest arrhythmias encountered in ER or EP lab
• Vagal manoeuvres and adenosine are the treatments of choice for the acute
therapy of SVT, and may also provide important diagnostic information
• Cath. ablation is the treatment of choice for all re-entrant and most focal
arrhythmias
• Sotalol is not recommended in treatment of SVT.
• Flecainide or propafenone are not recommended in patients with LBBB, or
ischaemic or structural heart disease

59. THANKS
Any Questions?