Novel Cardiac Pacing to Initiate Cardiac Remodeling in Heart Failure

The project studies subjects with non-ischemic cardiomyopathy who have a pacing device already implanted. Subjects randomized to the pacing intervention versus a sham intervention will be compared for various symptomatic, functional and other outcomes. Each subject will undergo baseline quality of life/symptom questionnaires and clinical testing for cardiac functional/structural effects and exercise tolerance, then the intervention vs. sham (subjects blinded to their category), followed by repeat questionnaires and clinical testing. Medical record review will be undertaken to establish demographic variables, baseline and follow up testing results.

• novel atrial pacing approach (Other): See US Patent #10987516. An atrial pacing method that preserves atrioventricular and interventricular synchrony to reproduce an exercise-typical envelope of heart rate.
• sham pacing approach (Other): A pacemaker/ICD interrogator/programmer will be used to simulate changes in pacing rate over the same time period as the intervention group but the programming changes will not actually be implemented and not change in paced heart rate will occur.

Primary outcomes

• Quality of life/symptom score [4 weeks after start of the protocol]: Minnesota Living with Heart Failure Score (range 0-105, higher scores indicate worse quality of life)

Secondary outcomes

• systolic blood pressure [every 5 minutes during intervention/sham in weeks 1-4 of the protocol]: systolic blood pressure (mmHg) as a continuous variable
• diastolic blood pressure [every 5 minutes during intervention/sham in weeks 1-4 of the protocol]: systolic blood pressure (mmHg) as a continuous variable
• Oxygen saturation [every 5 minutes during intervention/sham in weeks 1-4 of the protocol]: oxygen saturation by pulse oximeter (%) as a continuous variable
• cardiac output [every 5 minutes during intervention/sham in weeks 1-4 of the protocol]: cardiac output (liters/minute) as measured by thoracic impedance and reported as a continuous variable
• MACE [4 weeks and 4 months after start of the protocol]: Major adverse cardiac events: composite of total death, MI, stroke, hospitalization due to heart failure, revascularization
• six minute walk [at the time of enrollment, and at 4 weeks after start of the protocol]: distance ambulated in 6 minutes (meters)

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Non-Ischemic Cardiomyopathy
* Ejection Fraction </= 35% despite at least 3 months stable standard medical management
* New York Heart Association Class II-III symptoms
* Dual chamber implantable cardioverter defibrillator in place or Biventricular ICD in place (over 3 months old)
* Normal Atrioventricular conduction or Biventricular ICD
* QRS < 120 msec (inherent conduction or paced with BiV ICD)

Exclusion criteria:

* Age < 18 years
* Inability to ambulate safely
* Congenital or primary valve disease
* Left Ventricular thrombus
* Severe peripheral arterial disease
* Admission for life-threatening condition (eg heart failure, stroke) in the past 3 months
* Major surgery in the past 3 months or anticipated during the period of the trial
* Paced or intrinsic QRS >120 msec
* Life expectancy < 1 year
* Hemodialysis
* Hematocrit < 30%
* Severe Chronic lung disease
* Pregnancy
* ICD battery longevity < 1 year
* Unsuppressed atrial arrhythmias
* Already participating in an exercise programusion Criteria

• Denice Hodgson-Zingman, MD, Principal investigator, University of Iowa