Dr Eric Prystowsky

1
The EP show biventricular pacing in CHF

• Dr Eric Prystowsky
• Director
• Clinical Electrophysiology Laboratory
• St Vincent Hospital, Indianapolis
• Dr Leslie Saxon
• Chief, Electrophysiology Laboratory and
  Implantable Device Services
• University of California in San Francisco
• San Francisco, CA
• Dr Angelo Auricchio
• Director, Cardiac Catheterization Laboratory
• University of Magdeburg
• Magdeburg, Germany

2
Pacing in heart failure

• While only 5-10 of advanced heart failure
  patients have traditional indications for
  bradycardia pacemakers, many of them have
  conduction disease prolonged PR intervals or
  bundle branch blocks.
• In early, non-randomized trials, programming the
  AV delay to about 100 ms in standard RA and RV
  pacemakers in decompensated class IV heart
  failure patients resulted in dramatic
  improvements in pump function.
• In controlled clinical trials, no universal
  right-sided delay was found to improve pump
  function.

3
Improving left- and right-sided delays

• A subset of patients with marked prolongation of
  their PR interval and mitral regurgitation may
  benefit from an ultra-short AV delay in the range
  of 100 ms.
• It was also thought that the 30 of patients with
  dilated heart failure who have a left bundle
  branch block might benefit from pre-excitation,
  reducing the delay in left sided activation
  contraction.
• Current studies in biventricular stimulation are
  now ongoing.

4
PATH-CHF
Pacing therapies for congestive heart failure

• In an original substudy, patients with class III
  and IV heart were implanted with ventricular
  resynchronizers (VRs). They were treated for
  1-month with pacing, 1-month with the VR turned
  off (without the patients knowledge), and a
  further 1-month with stimulation. Investigators
  measured heart rate, heart rate variability, and
  oxygen consumption.
• A second study looked at left ventricular pacing
  alone compared to biventricular pacing.

5
PATH-CHF
Pacing therapies for congestive heart failure

• Measurement of acute hemodynamic responses
  revealed 2 different patient populations with
  regard to the effect on the QRS complex.
• Patients with a wide QRS complex, wider than 150
  ms, all behave as responders.
• Other patients may not respond acutely to any
  shortening of the AV delay, and may even
  demonstrate substantial hemodynamic worsening.

6
Biventricular pacing
Transvenous approach to epicardial pacing

• A lead may be passed through the coronary sinus
  and into the venous system, obviating the need
  for screw-in epicardial lead implants.
• Approximately 5-10 of patients have some
  anatomical aberrancy and cannot be implanted
  using the transvenous approach.
• The ability to lodge the lead in the terminal
  vessels to get adequate LV pacing down far enough
  off the AV groove is also an issue.
• This technology still needs refinement so that
  these leads can be implanted widely and safely.

7
Pacing as therapy for CHF

• To date, the patients who improve the most have
  the widest QRS intervals and more advanced heart
  failure. In these patients, improvements in VO2
  and walking distance up to 20-25 have been
  noted.
• Early echo data shows that chronic pacing for as
  short as 3 months prevents the progressive
  remodeling of the ventricle.
• Insufficient data currently exist regarding the
  effects of pacing in right bundle branch block.

8
Pacing as preventive therapy for CHF

• I guess the question Leslie is throwing on the
  table, and I've heard it from others, and I think
  it's intriguingif you take somebody who has
  class II heart failure with a left bundle, or
  left IVCD, and prophylactically pace them, will
  you prevent the development of class III
  failure?
• Dr Eric Prystowsky
• Director
• Clinical Electrophysiology Laboratory
• St Vincent Hospital, Indianapolis

9
Additional randomized trials in biventricular
pacing

• The COMPANION trial looks at mortality and
  hospitalization in CHF patients using
  biventricular stimulation alone, or biventricular
  therapy coupled with an ICD, compared to standard
  drug therapy.
• The MUSTIC trial (Multisite Stimulation in
  Cardiomyopathy) randomized 58 heart failure
  patients into 2 study arms using a cross-over,
  single-blinded design. The first arm started with
  BVP, the second with no BVP - after 3 months the
  pacing modes were switched.

10
MUSTIC trial results (i)
Overall results of BVP vs no BVP
BVP vs no BVP Percentage change p value
Distance walked in 6-minute period 23 0.0001
Peak VO2 (mL/min/kg) 8 0.0158
Quality of life 30 0.0002
BVP biventricular pacing primary endpoint
secondary endpoint
11
MUSTIC trial results (ii)

• The MUSTIC trial had a 5 mortality rate during
  the 6-month crossover period.
• 2 deaths were classified as sudden death 1
  occurred after 26 days in the BVP mode, 1
  occurred after switching the pacemaker from
  inactive to active mode.
• The third death was due to heart failure
  decompensation.
• No data have yet shown that biventricular pacing
  promotes arrhythmic death.

12
PACMAN trial

• The PACMAN trial is a randomized trial with 2
  arms, comparing biventricular stimulation versus
  no stimulation over time. Therapy is maximized
  for ACE inhibitors, beta-blockers and diuretics.
• Endpoints include improvement in exercise
  capacity, oxygenation and changes in total
  comorbidities.
• Follow-up will be at least 1 year per patient.