Lessons from the EP lab

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Lessons from the EP lab

• Reversal of Idiopathic Cardiomyopathies

Steven Compton, MD, FACC, FACP Alaska Heart
Institute
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Idiopathic Cardiomyopathy

• A disease of unknown etiology that principally
  affects the myocardium

Gilbert, EM and Bristow, MR, in Schlant and
Alexander The Heart 8th ed., 1994.
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Idiopathic Cardiomyopathy

• Diagnosis is established by the presence of LV
  dilatation and systolic dysfunction in the
  absence of congenital, coronary, valvular,
  hypertensive, or pericardial heart disease.

Gilbert, EM and Bristow, MR, in Schlant and
Alexander The Heart 8th ed., 1994.
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Idiopathic Cardiomyopathy

• Distinct from secondary myocardial diseases that
  occur with a specific systemic disorder that may
  be metabolic, collagen-vascular, infiltrative,
  neuromuscular, inflammatory, toxic, genetic, or
  neoplastic in origin.

Gilbert, EM and Bristow, MR, in Schlant and
Alexander The Heart 8th ed., 1994.
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Idiopathic Cardiomyopathy

• Since IDC is defined clinically, it is likely
  that several specific etiologies are responsible
  for this condition.

Gilbert, EM and Bristow, MR, in Schlant and
Alexander The Heart 8th ed., 1994.
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Idiopathic Cardiomyopathyno longer

• Tachycardia induced cardiomyopathy
• Atrial fibrillation-induced cardiomyopathy
• Ventricular ectopy-induced cardiomyopathy
• Dyssynchronous cardiomyopathy

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Tachycardia-induced cardiomyopathy

• Caused by any sustained, fast rhythm
• Atrial rhythms
• Afib, Aflut, AT
• AVRT, esp. PJRT
• AVNRT
• VT
• Idiopathic VTs
• Ischemic VTs
• BBRT VTs
• Sustained rapid pacing

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Tachycardia-induced cardiomyopathy

• Clinical clues dating back to 1910
• Reversal with ablation demonstrated late
  80s/early 90s
• Review article 1997 (Shinbane et al, JACC)
• Heart rate and rhythm control should be
  rigorously and rapidly pursued if definite signs
  of a cardiomyopathic process have developed.

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TICM Findings

• Ventricular cardiomyopathy
• Gross changes
• Dilated ventricle
• Reduced LV contractility
• Elevated LV end-diastolic pressure
• Mitral regurgitation (2? to annular dilatation)
• Abnormal LV torsion
• LV diastolic dysfunction

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TICM Microscopic changes

• Myocyte lengthening, hyperplasia
• Disruption of basement membranesarcolemmal
  junction
• Reduced myocardial capillaries and reduced blood
  flow
• Impaired coronary reserve
• Myocardial fibrosis

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Molecular changes

• ß-receptor expression reduced, transduction
  reduced
• Reduced adenylate cyclase activity
• Abnormal excitation-contraction coupling
• T-tubule depletion
• Apoptosis

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Atrial cardiomyopathy

• Atrial dilatation
• Contractile dysfunction
• Abnormal calcium channel function
• Na/Ca2-exchanger upregulation
• Intracellular Ca2 loading

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Clinical observations

• LV dysfunction correlates with
• Tachycardia rate
• Tachycardia duration
• Ventricular vs. atrial mechanism
• Reports of reversal with ablation relate to
  grossly observed LV contractility. Reversal of
  LV dysfunction may not be complete.

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Afib induced CM

• 36 y/o WM with lone afib
• Normal echo and thyroid studies. Holter mean
  rate 74 bpm.
• 3 years later
• Exertional intolerance. LVEF 30, mild MR.
  Fails dofetilide, declines amiodarone.

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Atrial fibrillation ablation
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Post ablation

• 4 weeks post ablation
• Bags fall moose, 3 mile haulout
• Back to full activity
• 6 months post ablation
• Persistent NSR
• Normal LV function
• 2 years post ablation
• NSR, Normal LV

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Catheter Ablation for Atrial Fibrillation in
Congestive Heart Failure
Li-Fern Hsu, M.B., B.S., Pierre Jais, M.D.,
Prashanthan Sanders, M.B., B.S., Ph.D., Stephane
Garrigue, M.D., Ph.D., Meleze Hocini, M.D.,
Frederic Sacher, M.D., Yoshihide Takahashi, M.D.,
Martin Rotter, M.D., Jean-Luc Pasquie, M.D.,
Ph.D., Christophe Scavee, M.D., Pierre Bordachar,
M.D., Jacques Clementy, M.D. and Michel
Haissaguerre, M.D.
N Engl J Med Volume 351232373-2383 December 2,
2004
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Improvement in Left Ventricular (LV) Function and
Dimensions after Ablation in Patients with
Congestive Heart Failure
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Hsu, L. et al. N Engl J Med 20043512373-2383
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AF Cardiomyopathy

• Restoration of sinus rhythm by ablation of AF in
  CHF can significantly improve cardiac function,
  symptoms, exercise capacity, and quality of life.
• Cardiomyopathy can improve or resolve despite
  prior rate control.
• Mechanisms of improvement?
• Regularization of ventricular activation?
• Restoration of atrial transport function?

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AF Cardiomyopathy

• AVN ablation/BIV vs PVI trial rate controlled
  patients

Khan et al, N Engl J Med 20083591778-85.
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PVC-induced Cardiomyopathy
LVEF 40 NYHA III
LVEF 55 NYHA I
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PVC-induced Cardiomyopathy

• Resolves with treatment
• First description 2000 (Chugh et al JCVEP)
• Independent of PVC source
• RVOT
• LV septum
• Ischemic scar
• Mechanism?

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Dyssynchronous Cardiomyopathy
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Case Report

• 58 y/o IDC EF 10, Class IV CHF
• Bimonthly hospitalizations for CHF
• Maximally tolerated medical therapy

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Carl Kron
Marked First Degree AV block LBBB
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Class IV
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Epicardial LV Lead
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Class IV
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Class II
Class IV
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LVEF 10 NYHA IV
LVEF 50 NYHA I
2002
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Super-responders

• Decrease in New York Heart Association functional
  class 1
• 2-fold or more LVEF increase or final LVEF gt45,
• and
• Decrease in LV end-systolic volume gt15

Antonio et al, Europace 2009 11(3)343-349
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Super-responders

• Definitions vary but involve restoration of
  near-normal or normal LV function.
• 7-22 of CRT patients super-respond
• Predictors absence of scar, shorter duration of
  dysfunction, less LV dilatation.
• Implies existence of dyssynchrony as sole cause
  of cardiomyopathy in some patients.

Antonio et al, Europace 2009 11(3)343-349 Ypenbur
g et al, JACC 2009 53(6)483-490
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Dyssynchronous Cardiomyopathy
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Idiopathic Cardiomyopathyno longer

• Tachycardia induced cardiomyopathy
• Atrial fibrillation-induced cardiomyopathy
• Ventricular ectopy-induced cardiomyopathy
• Dyssynchronous cardiomyopathy