Restoration of Atrioventricular Synchrony Trial

Inclusion Criteria: * Meet current indications for an implantable cardioverter-defibrillator (ICD) implant with: * QRS width \< 120 msec * Left ventricular ejection fraction (LVEF) \< 35% (no more than 180 days prior to enrollment) * NYHA functional class II/III * Optimal pharmacological heart failure therapy * PR interval \>/= 230 msec * Ability to tolerate protocol required programming * Access to a telephone line compatible with the LATITUDE® Communicator * Subjects in sinus rhythm at the time of the baseline visit and who are expected to remain in sinus rhythm for the duration of the study * Age 18 or above, or of legal age to give informed consent specific to state and national law * Willing and capable of providing informed consent, undergoing a device implant, participating in all testing associated with this clinical investigation at an approved clinical investigational center and return to the investigational center at the intervals defined by this protocol Exclusion Criteria: * Previously placed pacemaker, ICD, or CRT device * Inability or refusal to sign the Informed Consent Form * Documented life expectancy of less than 12 months or expected to undergo heart transplant within the next 12 months * Have tricuspid valve disease or who are likely to receive a mechanical tricuspid valve during the course of the clinical investigation * Inability or refusal to comply with the follow-up schedule * Have a neuromuscular, orthopedic, or other noncardiac condition that prevents subject from normal unsupported walking for the six minute hall walk test * Have surgically uncorrected primary valvular heart disease * Second or third degree atrioventricular block (AVB) * Permanent or persistent atrial tachyarrhythmia that is refractory to all therapies * Have had cardiac surgery, percutaneous coronary intervention, or myocardial infarction within 3 months of signing consent or who are likely to undergo a cardiac surgery or procedure in the foreseeable future * Enrolled in any concurrent study unless written approval has been obtained from Boston Scientific or The Integra Group * Women who are pregnant or plan to become pregnant