1. Supraventricular Tachycardia and Atrial Fibrillation
Courtney Bunevich, D.O.
August 15, 2007

2. SVT: Clinical Features
Regular, rapid rhythm
Usually narrow complex rhythm
Arises from atria or atrioventricular nodal tissue above the bundle of His that initiate and maintain the rhythm
Either a reentry or an ectopic pacemaker above the bundle of His

3. SVT: Pathophysiology Reentry: SVT associated with reentry is PSVT
AV nodal reentry (AVNR) occurs in 60% of cases
Orthodromic AVNR is antrograde conduction via AV node and retrograde conduction via accessory pathway
AV reentry via an accessory pathway in 30%
Intra-atrial reentry s/p cardiac surgery after large atrial incision with scar formation
Sinus node reentry, inappropriate sinus tachycardia, ectopic junctional tachycardia, and nonparoxysmal junctional tachycardia are rare

4. PSVT: Clinical Features
Can occur in a structurally normal heart
Can be associated with rheumatic heart disease, acute pericarditis, MI, MVP, and preexcitation syndromes.
Exacerbated by caffeine, alcohol, illicit drugs, hyperthyroidism, diet supplements, herbal supplements (ginseng). Can be induced by PACs and PVCs

5. PSVT: Signs and Symptoms
Sudden onset and termination
Can occur in patients of all ages
Regular, tachycardia
Palpitations, anxiety, diaphoresis, lightheadedness, chest pain, dyspnea, pounding in chest and neck.
Syncope is uncommon
Polyuria if SVT prolonged secondary to release of atrial natriuretic peptide

6. Differential Diagnosis
Atrial fibrillation/ Atrial flutter/ MAT
Onset usually in patients > 60 y/o
Patients usually heave heart disease
Irregularly Irregular rhythm
Ventricular Tachycardia
Patients usually > 50 y/o
Patients usually have IHD
Present with syncope and SCD
Wide complex regular rhythm
Abrupt onset

7. Physical Exam
Patient can be diaphoretic, anxious, hypotensive, or even asymptomatic
Prominent jugular venous A wave from atrial contraction against closed tricuspid valve “frog sign”

8. Emergency Care
Get immediate set of vital signs including pulse oximetry, IV, O2, monitor.
EKG
CKMB and Trop I, TSH, FT4
BMP
Connect patient to continuous 12 lead EKG
Is patient stable? Do they need immediate cardioversion?

9. EKG The EKG in PSVT is usually a narrow, regular complex tachycardia.
Less than 10% of cases will have SVT with aberrancy
To be discussed later

11. Treatment
Try a vagal maneuver to slow rhythm to see the underlying rhythm.
Carotid sinus massage
Do if no bruits auscultated and no known carotid disease
Massage for 5 seconds and release
Can also place an ice pack on the forehead

12. Treatment Adenosine Causes flushing, CP, dyspnea
Half life is 15 seconds
First line treatment is Adenosine 6 mg IVP
If unsuccessful, give Adenosine 12mg IVP x 2
Cause transient AV nodal block by hyperpolarization of the node
Complications include bronchospams and VF
Will not work if patient has heart transplant
C/I if wide complex tachyarrhythmia
Caution in patients with severe COPD
Adensione 6mg terminate in 60-80% patients
Adenosine 12mg will terminate in 90-95% of patients

14. Treatment Next line treatments:
Verapamil mg /kg IV can repeat in 30 min. Hypotension can occur but can prevent this by giving CaCl2 10% 4mL. Not commonly used.
Diltiazem mg bolus then continuous infusion in at 5-15 mg/hour
Esmolol protocol
Metoprolol 5mg IV q5 x 3

15. Treatment
Consider cardioversion or venous atrial or ventricular temporary pacing if unable to slow rhythm down with adenosine, CCB, and BB before giving antiarrhythmics.
Can also give IV flecainide, IV procainamide, IV propafenone, IV ibutilide
These drugs can cause hypotension, bradycardia, and are proarrhythmic.

16. Synchronized Cardioversion
Should be used immediately in any unstable patient with hypotension, pulmonary edema, chest pain, or other unstable signs.
Required dose is usually small: 50 Joules

17. Long term Treatment
Risk of developing long term PSVT after single episode not defined. One episode is not indication for long term treatment.

18. Long term Treatment SVT with No Preexcitation
Verapamil, Beta blockers, and Diltiazem
Decrease symptoms in 30-60%
Randomized clinical trials show no superiority
Failure on a single drug therapy can try a combo of two or add one a class IC or class III antiarrhythmic
Long term treatment with class IC not recommended, and patents should be referred for catheter ablation

19. Catheter Ablation Radiofrequency and Cyrothermal
95% success rate initially
<5% recurrence rate in the 1st few months
Complications occur in 2-3%
Damage to arteries, bleeding, AVF, venous thrombosis, PE, myocardial perforation, valvular damage, systemic embolism, and death (rare)
Blocking near the AV node can cause total block of the AV node and patient will need a pacemaker

20. Wolf Parkinson White Associated Ebstein’s anomaly
EKG will show a short PR interval, a delta wave, and a QRS interval up to 0.12 msec
Accessory pathway is the Bundle of Kent

23. Wolf Parkinson White Has 2 mechanisms for PSVT
Orthodromic, narrow complex (95%)
Antrograde conduction via AV node and retrograde conduction via accessory pathway
Can treat like PSVT
Antidromic, wide complex (5%)
Antrograde conduction via accessory pathway and retrograde conduction via AV node
DO NOT give Digoxin, BB, Verapamil
Try procainamide and cardioversion

25. SVT with WPW Catheter ablation is the treatment of choice once stable
Risk of sudden death is 0.15 – 0.45 % / year

26. Wolf Parkinson White Can degenerate into Atrial Fibrillation
If life threatening: do immediate cardioversion.
If not unstable, you can try procainamine, amiodarone, or lidocaine
Caution verapamil, BB, and digoxin will cause degeneration into ventricular fibrillation!!

27. SVT with aberrancy Occur in less than 10% of cases
Regular, wide complex tachycardia
Causes:
SVT with a preexcitation syndrome
Antidromic reentry seen in <5% cases of patients who have WPW
Patient with a preexisting BBB
Bundle branch fatigue in PSVT

30. Atrial Fibrillation
Uncoordinated atrial activation with deterioration of atrial mechanical dysfunction
Ventricular response to atrial fibrillation depends on the integrity and electrophysical properties of the AV node
Most common arrhythmia encountered in clinical practice

31. Atrial Fibrillation
Most common sustained tachyarrhythmia patients seek treatment for
Affects 0.4-1% of the general population and 8% of patients greater than 80 years old
AF occurring in patient without structural heat disease and less than 65 y/o is termed lone AF
Types:
First episode
Paroxysmal (self-terminating)
Persistent (requiring electrical or pharmacological treatment)
Permanent

32. Atrial Fibrillation Irregularly, irregular rhythm
Can be associated with rapid ventricular conduction/response or AF with RVR
No atrial kick in atrial fibrillation. The firing of the atria and ventricles is not synchronized. In patients with systolic dysfunction, the atria makes an important contribution
Biopsies have shown patchy fibrosis of fibers in atria
Foci can be found in atria, pulmonary arteries, coronary sinus
Atrial rate is beats/min
Multiple small areas of the atria are firing and contracting (quivering)
Ventricular conduction rate is variable bpm

33. Causes for Atrial Fibrillation
Rheumatic heart disease
Nonrheumatic mitral valve disease disease
Hypertension
Chronic lung disease
ASD
Thyrotoxicosis *
Lone AF
Ischemic heart disease
Acute MI *
Dilated cardiomyopathy
Holiday heart- Alcohol ingestion *
Theophylline toxicity
Pheochromocytoma

34. Causes for Atrial Fibrillation
Pericarditis *
Electrocution *
Post cardiothoracic surgery *
Myocarditis *
Pulmonary embolism *
Obesity
Intracardiac tumors or thrombi
Amyloidosis
SAH or CVA
Familial AF

35. Signs and Symptoms Can be severe:
Pulmonary edema, palpitations, angina, and syncope
Relatively asymptomatic
Nonspecific symptoms such as fatigue

36. Treatment of AF with RVR
Get an immediate set of vitals, pulse oximetry. Place a patient on a monitor and O2. Get IV access.
Get EKG. Check BMP.
Check CKMB and Trop I. Get CXR.
Check TSH and FT4.
How long has AF been present? <48hrs or >48hrs or unknown
Is patient unstable? Do they need immediate cardioversion?

38. Treatment of AF with RVR Rate Control
Medications: IF preserved EF > 40%
Diltiazem mg IV bolus and run a drip in at 5-15 mg/hour. Can repeat the bolus if needed.
Esmolol protocol
Metoprolol 5mg IV q5 min x 3

39. Treatment of AF with RVR Rate Control
Medications: If EF < 40%
Recommend:
Diltiazem mg IV bolus and run a drip in at 5-15 mg/hour. Can repeat the bolus if needed.
Amiodarone 150mg IV over 1 minute then 1 mg/minute for 6 hours then 0.5 mg/min for 18 hours
Caution if patient on digoxin
Watch for hypotension
Low efficacy for acute conversion

40. Treatment of AF with RVR Rhythm Control
If duration is < 48 hours and EF > 40%
DC Cardioversion at 100 Joules (60%) , 200 Joules (80%)
ONLY ONE of the following: Amiodarone, ibutilide, flecainide, propafenone, and procainamide

41. Treatment of AF with RVR Rhythm Control
If duration < 48 hours and EF< 40%
DC cardioversion or Amiodarone

42. Treatment of AF with RVR Rhythm Control
If duration > 48 hours or unknown
Do rate control. Start anticoagulation for 4 weeks with therapeutic INR. Exclude clot. Do cardioversion. Continue anticoagulation for 4 more weeks.
Begin IV heparin. TEE exclude clot. Cardioversion. Anticoagulation for 4 weeks.

43. TEE
TEE will show thrombus in 5-15% in atrial fibrillation preparing for cardioversion
Thromboembolic events have been reported after “normal” TEE and cardioversion
Contrast enhanced MRI is evolving diagnostic modality for evaluation intracardiac thrombi
Statins have been shown to decreases risk of recurrent AF after cardioversion possible due to anti-inflammatory affects

44. Atrial Fibrillation
AFFIRM trial 2002 showed no mortality differences between rate and rhythm control groups. Rhythm control should be reserved for patients who are symptomatic even when rate controlled.
Patients need either rate or rhythm control and anticoagulation

45. New Onset AF Minimal Evaluation:
H and P for symptoms, type of AF, date of onset and duration, treatment given, co-morbid or predisposing conditions
ECG- evaluate rhythm, LVH, preexcitation syndromes, BBB, and old MI
TTE- evaluate LV function, clots (inferior), valvular disease
Labs: TSH, Renal and Hepatic function

46. New Onset AF Additional Testing:
6 minute walk test to assess for adequate rate control
Exercise stress test
Holter monitor
TEE
Electrophysical studies

47. Atrial Fibrillation
AFFIRM trial showed that patients despite being in sinus rhythm are still at high risk of stroke.
Patients with paroxsymal AF still must be anticoagulated.
CHADS2: criteria recommended that scores 0-2 can use aspirin safely and scores greater than 3 need warfarin in those with nonvalvular AF
CHF – 1 point
HTN – 1 point
Age > 75 years – 1 point
DM – 1 point
Prior Stroke or TIA – 2 points

48. CHADS2 Score: Stroke rate per year (%): 1 2 3 4 5 6 1.9 2.8 4.0 5.91 2 3 4 5 6
Stroke rate per year (%):
1.9
2.8
4.0
5.9
8.5
12.5
18.2

49. Risk of Stroke
Atrial fibrillation is associated with increased risk of stroke, heart failure, and all cause mortality
5% per year risk of CVA in patients with nonvalvular atrial fibrillation
Framingham study showed 17 times increased risk of CVA in patients with valvular AF and 5 times increased risk in those with nonvalvular AF
1.5% risk of CVA in patients age 50-59
23.5% risk of CVA in patients age 80-89

50. Risk of Stoke NYHA classification: Risk of stroke/year (%): I II-IIIIV
Risk of stroke/year (%): 4%
12-26%
27-50%

51. Risk of Stroke Risk Factors: Relative Increased Risk: CVA/TIA DM HTNHF
Age per decade
Relative Increased Risk:
2.5
1.7
1.6
1.4

52. ASA Treatment
Treat of AF with ASA is a Class I recommendation by the 2006 ACC guidelines in the following subsets of patients:
Age < 60 and no heart disease
Age with heart disease and no risk factors
Age and no heart disease
Risk factors: Heart failure, EF<35%, HTN

53. Pharmacologic Cardioversion
Ibutilide is the only drug FDA approved for pharmacologic cardioversion
45% conversion rate for AF
60% conversion rate for Atrial Flutter
Class III agent with a 4-8% risk of TdP
Higher if patient has CHF or cardiomyopathy
0.01mg/kg (max 1 mg) over 10 minutes
Have external defibrillator ready
Monitor of telemetry for at least 4 hours

54. Pharmacologic Cardioversion
Digoxin and sotalol are NOT recommended for pharmacologic cardioversion
These drugs gave Class I and IIa recommendations for pharmacologic cardioversion:
Dofetilde
Flecanide
Propafenone
Ibutilide
Amiodarone (IIa)

55. Electrical Cardioversion
Recommended if symptoms are known to be less than 48 hours
Unstable in patients without accessory pathway
Unstable or in tachycardic patients with an accessory pathway
Patients unable to tolerate symptoms
Contraindicated in hypokalemia and digitalis toxicity

56. Other Treatments Maze procedure
Can do as an adjunct procedure during open heart surgeries
Catheter ablation after EP studies to determine irritable foci
AVN ablation can be useful in patients with tachycardia-mediated cardiomyopathy
Small study showed increase in EF from 26% to 34% after AVN and pacemaker implantation

58. References Harrison’s Internal Medicine 16th Edition
2006 ACC Guideline for Atrial Fibrillation
New England Journal of Medicine
Supraventicular Tachycardia
9 March pp volume 354
American Journal of Emergency Medicine
Wide Complex Tachycardias: Beyond Traditional Differential Diagnosis of Ventricular Tachycardia versus SVT with Aberrant Conduction
November pp 876 volume 23
AFFRIM Trial pp volume 347