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THE SURGICAL CURE OF ATRIAL FIBRILLATION

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Propensity matched groups of patients with or w/o AF preoperative ... events in the atrium during a bout of Paroxysmal aF are identical to those of Chronic AF ... – PowerPoint PPT presentation

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Title: THE SURGICAL CURE OF ATRIAL FIBRILLATION


1
THE SURGICAL CURE OF ATRIAL FIBRILLATION
  • Harold G. Roberts, Jr., M.D.

2
Survival after CABG
Propensity matched groups of patients with or w/o
AF preoperative Kaplan Meier estimates _at_ five
years with 68 CI of pts remaining _at_ risk shown
in parenthesis
3
DefinitionsACC AHA ESC
  • Recurrent Atrial Fibrillation 2 or more
    episodes
  • Paroxysmal atrial fibrillation
  • Duration lt 7 days, terminates spontaneously
  • Persistent Atrial Fibrillation
  • Does not terminate spontaneously, requires
    electrical or pharmacolgoical intervention to
    create sinus rhythm
  • Permanent Atrial Fibrillation
  • SR cannot be sustained after cardioversion

4
DEFINITIONS JL Cox
  • Paroxysmal atrial fibrillation is intermittent
  • Chronic atrial fibrillation is continuous
  • A person who has Paroxysmal (intermittent) atrial
    fibrillation for a long time does not have
    Chronic atrial fibrillation
  • Once atrial fibrillation is established, all
    atrial fibrillation is the same. The electrical
    events in the atrium during a bout of Paroxysmal
    aF are identical to those of Chronic AF

5
Atrial Fibrillation-Maintenance
  • Once atrial fibrillation is established
  • 1. It is characterized by multiple
    simultaneous
    macro-reentrant circuits in both atria
  • 2. It can spontaneously convert back to sinus
    rhythm (paroxysmal atrial fibrillation)
  • 3. It can continue indefinitely (chronic
    atrial fibrillation
  • Atrial Fibrillation begets atrial fibrillation

6
Consequences of AF
  • Impaired quality of life
  • Thromboembolic complications (stroke)
  • Progressive increase in atrial size
  • Concealed and overt tachycardiomyopathy
  • Overall Increased Mortality

7
Risks Associated with Atrial Fibrillation
  • A-Fib increases stroke rate 3 5 times
  • A-Fib is responsible for 15 20 of all strokes
  • A-Fib increases death rate 2 fold
  • The longer a patient is in A-Fib, the more
    difficult it is to treat and eliminate the rhythm

8
Percentages of Strokes Associated with Atrial
Fibrillation
9
Symptomatic Presentation of Atrial Fibrillation
10
AFFIRM TRIALRate Control vs. Rhythm Correction
  • Currently available AADs are not associated with
    improved survival, which suggests that any
    beneficial antiarrhythmic effects of AADs are
    offset by their adverse effects. If an effective
    method for maintaining SR with fewer adverse
    effects were available, it might be beneficial.

11
Conduction System ChangesResulting in Atrial
Fibrillation
  • Abnormal Cardiac Conduction
  • Cardiocytes lose ability to conduct in synchrony
  • Triggers from pulmonary veins cause wavelets of
    A-Fib
  • Wavelets form macro-reentry circuits that become
    self sustaining sources of A-Fib
  • SA node no longer communicates with AV node
  • Atrial tissue permanently changes

12
Pulmonary Vein Triggers Paroxysmal AF
Right Atrium
Left Atrium
Septum
superior vena cava
31
fossa ovalis
17
pulmonary veins
inferior vena cava
coronary sinus
11
6
94 of triggers are in the PVs
Haissaguerre NEJM 1998 339659-66
13
Causes of Atrial Fibrillation
  • Most conditions are related to enlargement or
    dilation of the atrial tissues
  • Mitral valve disease ( 30)
  • Hypertension
  • Ischemic heart disease
  • Congestive heart failure
  • Idiopathic (no known cause)

14
Muscular sleeves extending from the atrium along
the pulmonary vein are the nexus for propagating
arrhythmia triggers
15
Treatment Options for Atrial Fibrillation
  • Medical
  • Pharmacological
  • Electrical
  • Interventional Cardiology
  • Surgical

16
Drug Therapy for Atrial Fibrillation
  • Efficacy poor at best 40-60 maintenance of
    sinus rhythm.¹, ²
  • Proarrhythmia sinus and AV node dysfunction
  • Toxicity liver, pulmonary fibrosis, peripheral
    neuropathy
  • Patient issues quality of life and compliance

1Crijns HJ, et al. American Journal of
Cardiology. 199168(4)335-41. 2Antman EM, et al.
Journal of American College of Cardiology.
199015(3)698-707.
17
Treatment Options for Atrial Fibrillation
  • Electrophsyiological
  • EP Cardiology peripheral based therapies
  • Pulmonary vein isolation with fluoroguided
    catheters
  • Radiofrequency (RF) and cyrothermic energy
    sources

18
Cox-Maze III
  • Maze Procedure developed by J. Cox, M.D. in 1987.
  • Based on the principal that AF is caused by
    multiple reentrant circuits in the atria.
  • Cut and sew technique which efffectively blocks
    the propagation of these renentrant circuits into
    dead ends and allows the normal propagation of SA
    node stimuli

Cox J, et al. J Thoracic Cardiovascular Surgery
1991101509-583.
19
Catheter Ablation Challenges
  • Technically challenging to create continuous
    lesion
  • Transmurality not confirmed
  • Poor long term outcomes
  • Left Atrial Appendage not addressed
  • Uncontrolled energy complications
  • Esophgeal fistula, embolic events
  • Prolonged fluoro-radiation exposure

20
Radiofrequency Ablation
  • Charring
  • Thromboembolism
  • Significant tissue disruption
  • Difficult
  • Transmural probe contact limited
  • Lesion Depth
  • Potential for Injury

21
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22
Shortcomings of the Cox Maze Procedure
  • Requires cardiopulmonary bypass and an arrested
    heart
  • Adds to cross-clamp time
  • Few Surgeons perform the operation because of
    its complexity
  • Can lead to increases in morbidity
  • Increased length of stay
  • Pacemaker requirements

23
Left Atrial Anatomy
Ostia of Left Atrial Appendage
Mitral Valve
Left Superior Pulmonary Vein
Left Inferior Pulmonary Vein
Right Superior Pulmonary Vein
Right Inferior Pulmonary Vein
24
Posterior View of Heart
SVC
Right Superior Pulmonary Vein
Left Superior Pulmonary Vein
Left Inferior Pulmonary Vein
Right Inferior Pulmonary Vein
IVC
Coronary sinus
25
The AtriCure Bipolar Ablation System
26
Optimimal tissue contact ensures a discrete,
transmural lesion
27
Gross Pathology
Lesion through variable tissue thickness
28
Histology
29
MIS Approach Wolf Mini-MazeThe Next Step in
Evolution in Surgical Ablation
  • Sole paroxysmal and persistent AF patients
  • Bi-lateral pulmonary vein isolation 90
    success
  • Close left atrial appendage to manage stroke
  • Collaborate with EP partners with dual approach

30
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31
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33
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34
Oklahoma Group Observations
  • Hyperactivity of autonomic ganglia at the
    PV-atrial junctions can induce APDs and rapid
    firing from adjacent PVs providing the drivers
    for AF
  • Ablation of these ganglionic clusters can reduce
    the autonomic burden and thereby suppress the
    triggered firing as well as the substrate for
    converting PV ectopia into AF

35
What is the Role of the Ganglionic Plexi in A-fib
Propagation?
36
Working Hypothesis
  • Ectopic beats arising in the PVs can be converted
    into AF by the activity of the autonomic ganglia
    located at the PV-atrial junctions
  • Excessive release of cholinergic and adrenergic
    neurotransmitters can shorten refractoriness and
    induce triggered firing sufficient to cause AF

37

SVC
R1
RSPV
R3
R2
RA
LA
R4
R5
Waterstons Groove
RIPV
R6
R7
R8
R9
R10
IVC
Ganglionic Plexi - Right
38
Pulmonary Artery
L2
L1
LSPV
LA Appendage
L4
L3
Marshall Tract
L6
L5
LIPV
L8
LA
L7
LV
L10
L9
AV Groove
Ganglionic Plexi - Left
39
Right PVs and Ganglionated Plexi
RSPV
Anterior Right GP
Head
Foot
RIPV
Inferior Right GP
40
Left Pulmonary Veins and Location of Left GPs
Pulmonary Artery
Pericardial Insertion of Ligament of
Marshall (Region Superior Left GP)
Pericardium
LSPV
LIPV
Inferior Left GP
41
PV potentials in AF
42
Positive response to HFS
43
Isolated no potentials
44
Surgical Treatment of AF
  • Bipolar RF Ablation Clinical Results
  • Dr. Damiano
  • Washington University
  • 40 patients Modified Cox-Maze
  • 23 patients with 6 mo follow-up
  • 91 freedom A-Fib at 6 months

45
Cryo MazeResults n40, (3-15.5 mo, Post-op, mean
10.3 mo.)
  • Mini-maze 12
  • Full Maze 8
  • SR 35 (88)
  • AF 2 ( 5) (RHD)
  • PPM 2 ( 5)
  • Mortality 0
  • CVA TIA 1
  • ARDS 1
  • Bleeding 0
  • EP Interventions 0
  • Freedom from Recurrent AF 95

46
Lateral Right Atrium
47
Thank You
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