Arrhythmias and conduction disturbances after cardiac surgery

1
Arrhythmias and conduction disturbances after
cardiac surgery

• Anjan Gupta M.D.
• Milwaukee Heart Institute
• University of Wisconsin, Milwaukeeanjangupta_at_pol.
  net

2
Post cardiac surgery atrial arrhythmias
3
INCIDENCE OF ATRIAL FIBRILLATION OR FLUTTER
AFTER CABG
Reference No. of Pts
developing ECG Peak
incidence and
patients atrial fibrillation
documentation (days postop) Year
studied or flutter
No Percent
Buxton, 1981 99
29 29 COM, Holter
3 Fuller, 1989
1666 473 28
COM, Holter 2 Yousif,
1990 100 19
19 COM, ECG
lt3 Leitch, 1990 5807
999 17 COM, ECG
- Crosby, 1990
418 115 27
COM -
4
INCIDENCE OF ATRIAL FIBRILLATION OR FLUTTER
AFTER CABG

• Reference No. of
  Pts developing ECG
  Peak incidence atrial
  fibrillation
• and patients
  or flutter documentation
  (days postop)
• Year studied

No Percent
Klein, 1995 54
16 30 COM, ECG
- Frost, 1995
128 38
30 COM, Holter
- Frost, 1995 120
35 29
COM, ECG -
Mendes,1995 168 57
34 COM, Holter
3 Augostini 96
33 9 24
COM, ECG -
5
FACTORS ASSOCIATED WITH POST CABG ATRIAL
FIBRILLATION AND FLUTTER

• PREOPERATIVE FACTORS

Reference and No. of patients
Significant predictive factors
Year studied

Buxton, 1981 99
P wave duration
Fuller, 1989 1666
Age, preop digoxin treatment
Yousif, 1990 100
Myocardial ischaemia
Leitch, 1990 5807
Age, COPD, CRF, HTN, Preop diuretic,

Preop beta blocker, CTRgt0.5, LM or 3
vessel CAD Crosby, 1990
1990
Age
6
FACTORS ASSOCIATED WITH POST CABG ATRIAL
FIBRILLATION AND FLUTTER

• PREOPERATIVE FACTORS

Reference and No. of patients
Significant predictive factor Year
studied
Klein, 1995 54
P wave duration on Signal averaged
ECG Frost, 1995 102
Age, low vagal tone, ectopic SV
beats, NSSVT Mendes, 1995
168 Severe RCA disease,
age, male gender Augostini, 1995
33
Age Asher, 1996
2196 Age, Internal
mammary conduit

7
FACTORS ASSOCIATED WITH POST CABG ATRIAL
FIBRILLATION AND FLUTTER

• PEROPERATIVE FACTORS

Reference and No. of patients
Significant predictive factor Year
studied
Capucci,1987 50
Atrial conduction delay Yousif, 1990
100 Adj.
coronary endarterectomy,

topical cardiac cooling Leitch,1990
5807 More than 3
distal anastomosis Lowe, 1991
1991 Pace inducibility of atrial
fibrillation
8
FACTORS ASSOCIATED WITH POST CABG ATRIAL
FIBRILLATION AND FLUTTER

• POSTOPERATIVE FACTORS

Reference and No. of patients
Significant predictive factor Year
studied
Fuller, 1989 1666
Postoperative beta blocker treatment, stroke
Frost, 1995 128
atrial ectopics, SVT, atrial
arrhythmias Augostini,
1995 33 sinus
cycle length, sinus node recovery time

sinoatrial conduction time
9
SIGNIFICANT PREOPERATIVE PREDICTORS OF
POSTOPERATIVE AFIB BY UNIVARIATE ANALYSIS
Predictor Relative Risk
(95 CI) p - value
History of Atrial fibrillation
2.00 (1.75 - 2.30) lt0.01
Valvular disease 1.50 (1.29 -
1.75) lt0.01 CHF
1.44 (1.26 - 1.65)
lt0.01 Vascular disease
1.27 (1.09 - 1.47) lt0.01
Mathew et al , JAMA 1996 276 300 - 306
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MULTIVARIABLE PREDICTORS OF POSTOPERATIVE AFIB
Predictors Odds Ratio
(95 CI) p - value
Hx of atrial fibrillation 2.28 (1.74
- 3.00) lt0.01 Pulmonary Vein
Venting 1.44 (1.13 - 1.83)
lt0.01 Male Sex
1.41 (1.09 - 1.81) lt0.01
Age (per 5-y increase) 1.24 (1.18 -
1.31) lt0.01
Mathew et al , JAMA 1996 276 300 - 306
11
Length of stay in hospital after postop atrial
arrhythmias
Creswell et al, Ann. of Thoac. Surg, 199356539
- 49
12
Incidence of V-Fib, V-Tach and stroke associated
with postop atrial arrhythmias
Creswell et al, Ann. of Thoac. Surg, 199356539
- 49
13
Day of onset of atrial fibrillation after CABG
Klein et al.Am Ht Jn, 1995129895 - 901
14
Prevalence of A-fib according to age at operation
Leitch et al, Jn of Th. Card Surg,1990100338-342

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Postoperative atrial fibrillation - Treatment

• Ibutilide - a new drug for atrial Fibrillation
  and Flutter
• Class III antiarrythmic drug
• In a randomized trial was proven to be superior
  to placebo in converting post op afib ( Kowey et
  al )
• A-flutter responds better than A-fib
• Adverse effects include development of Torsades

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Atrial Fibrillation
MANAGEMENT OF POST CABG AFIB
Post CABG Afib
Unstable
Stable
DC cardioversion
Rate control
Recurrent
Persists gt 48 - 72 hrs
AA drugs
IV/oral procainamide, quinidine
AA drugs
Effective
Anticoagulate
Ineffective
IV/PO procainamide, quinidine
Continue therapy
Effective
DC cardioversion
Ineffective
DC Cardioversion
Continue therapy
Add AA drugs if needed
Successful
Unsuccessful
DC Cardioversion
Continue drug
Anticoag, new drug
Successful
Unsuccessful
Continue drug
Anticoag, new drug
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Ventricular Tachyarrhythmias
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Ventricular arrhythmias

• EPIDEMIOLOGIC FEATURES
• Ventricular ectopy, including NSVT is seen in
  about 50 of patients after cardiac surgery
• Sustained VT and ventricular fibrillation occur
  rarely after cardiac surgery (0.4 - 1.4 reported
  in various studies)

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Ventricular arrhythmias
STUDIES OF VT AFTER CARDIAC SURGERY
Authors Patients Age (yr)
Incidence EF Time from op
Kron et al 18
1.4 38 15 2 days to 6 wks
Topol et al 12 64 8
0.72 39 10 2 days to 5 mth Sapin et
al 13 62 11
44 16 5 hr to 7 days Tam et al
16 59 10 0.68 25 4
1hr to 12 days Costeas et al 17
65 8 0.41 37 11 24hr to
15 days
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Ventricular arrhythmias

• DIAGNOSIS
• 12 Lead ECG
• Postoperative telemetry monitoring
• Bipolar atrial recording with epicardial wires

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Ventricular Arrhythmias
MANAGEMENT OF POST CABG VT/VF
Post CABG
Sust. Vent. Tachyarryth.
Ventricular Fibrillation
Ventricular tachycardia
Defib. IV Lido, Proc, Brety
Identify/Treat ppt factors
Recurrence
Unstable
Stable
No Recurrence
Use V-Fib Protocol
IV Lido, Procain, Brety
Use other IV drugs eg Amio
No further AA therapy
EPS guided AA therapy
Treat Ppt factors, Defib
Unsuccessful
Successful
Recurrence
No recurrence
Consider ICD therapy
Continue the drugs
No further therapy
Use V Fib recurr. protocol
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Ventricular arrhythmias

• Management of PVCs and NSVT
• Simple PVCs usually do not require Rx
• Frequent PVCs can be suppressed by atrial pacing
• If frequent and symptom producing can be
  suppressed with beta blockers or AA
• No role for prophylactic lidocaine
• Patients with NSVT and EF lt40 role of EP testing
  ?

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Ventricular Arrhythmias
Variables POVD
No POVD p - value
n 25
n 84
Age
62.8 9.7 56.2 7.5
0.0024 EF ()
66.2 9.3 66.1 9.6
0.95 CrossClamp time (min)
55.6 15 57.4 21.1
0.70 By-pass time (min)
111.8 2.5 111.0 33.9
0.91 Preop beta blockers
21 72
0.91 Preop Ca Ch blockers
17 66
0.41 Previous MI
8 25
0.97 LM disease
8
17 0.34 LAD
disease 22
74
0.74 Perioperative MI
4 7
0.46 PAD
11
19 0.30 Other Comp
2
13 0.53
Ferraris et al, J Cardiovasc Surg 19913212 - 19
24
Post cardiac surgery arrhythmias
Potential causes and precipitating factors

• Myocardial ischemia or infarction
• Hemodynamic instability
• Electrolyte abnormalities a) Hypokalemia, b)
  Hypomagnesemia
• Metabolic disturbances
• a) Acidosis, b) Alkalosis, c) Hypoxemia
• Drugs
• a) Sympathomimetics, b) Antiarrhythmics, c)
  Anesthetic
• Reperfusion effect
• Tissue trauma or inflammation, indwelling
  catheters
• Increase in catecholamines

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Conduction Disturbances

• Epidemiologic features and pathogenesis
• Transient conduction disturbances can occur in 4
  to 58 of patients after CABG
• RBBB is the most frequently noted abnormality
• Incidence of isolated AV block is low after CABG
  but may be higher after associated valve surgery

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Conduction Disturbances
Risk factors associated with Post CABG conduction
disturbances
Studies Significant Risk
Factors
Emlein et al , 1993 age gt 64,
LBBB Flack et al, 1992 use of cold
cardioplegia Caretta et al, 1991
LM disease
LAD stenosis, RCA occl
27
Conduction disturbances

• Intraventricular conduction defects
• Incidence of postoperative fascicular conduction
  defects vary from 3-5
• Longterm adverse prognosis is ascribed to
  appearance of new LBBB and nonspecific IVCD
• Postoperative LBBB has no immediate clinical
  impact and no specific Rx needed

28
Conduction disturbances

• First Degree AV block
• Most commonly due to fibrosis of AV node or
  toxicity of medications such as beta blockers or
  calcium channel blockers
• Other causes include edema of AV node region
  after mitral and aortic valve replacement
• No specific therapy is usually needed

29
Conduction disturbances

• Second-Degree AV block
• Mobitz Type I and Type II blocks are common after
  valve replacement surgery
• Drug effect or toxicity should be excluded as
  potential causes
• Temporary pacing may be needed depending on
  degree of AV block and HR as well as adequacy of
  lower escape rhythm

30
Conduction disturbances

• Complete AV block
• May be secondary to cardioplegia washout during
  immediate postoperative period or as a
  consequence of antiarrhythmic drug therapy
• It may be seen after valve replacement secondary
  to trauma of surgical manipulation in the area of
  AV node or bundle of HIS

31
Conduction disturbances

• Complete AV block
• Therapy depends on underlying heart rate and
  adequacy of underlying ventricular escape rhythm
• Discontinuation of all potentially offending
  drugs

32
Conduction disturbances

• Complete AV block
• Factors which predict low likelihood of recovery
  include calcified Aortic valve, delayed
  appearance of AV block and significant preop
  conduction defect
• In absence of excessive calcification, and in
  presence of a narrow complex escape rhythm with a
  good heart rate, PPM placement may be delayed up
  to 2 wks

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Meta-analysis of randomized control trials of
prevention of post-operative supraventricular
arrhythmias
Treatment RCT Total
Proportion of pts OR (95 CI) P-Val
Group
Patients with SVA ()
Rx Control
Verapamil 3 432
18.2 18.2 0.9 (.57-1.5)
0.69 Digoxin 5 507
14.2 17.6 0.9 (.6 - 1.5)
0.88 Preop beta- 6 478
8.1 40.1 0.2 (.1 - .3)
lt0.01 blocker Postop beta- 12
1071 8.9 32.3 0.3 (.2 -
.4) lt0.01 blocker
Andrews et al, Circulation 199184(suppl) 236 -
244