Clinical Research Directory

Inclusion Criteria: * Adults with bradycardia scheduled for pacemaker implant or heart failure patients indicated for cardiac resynchronization therapy (CRT) with one of the following: * Bradycardia with ventricular synchrony and QRS duration \< 110 ms in men or \< 100 ms in women or; * Bradycardia with left bundle branch block and QRS duration \> 140 ms in men or \> 130 ms in women or; * Bradycardia with right bundle branch block and QRS duration \> 130 ms in men or \> 120 ms in women or; * Heart failure with left bundle branch block and QRS duration \> 140 ms in men or \>130 ms in women. * Understands the nature of the study and is willing to comply with all study requirements. * Provides written informed consent. * A negative pregnancy test prior to the procedure for participants of child-bearing potential. Exclusion Criteria: * Complete AV block (3rd-degree AV block) without a stable escape rhythm or other circumstances where there is no measurable QRS. * Subjects with a previous or current pacemaker or defibrillator implant. * Anatomical or other conditions that may make a 12-lead ECG difficult to obtain, such as an allergy to components of the ECG pads, burns, open wounds, etc. * Currently enrolled in another investigational device or drug trial that has not completed the active treatment phase and/or would conflict with this study. * Other co-morbid condition(s) that could limit the participant's ability to participate in the study or to comply with study requirements or impact the scientific integrity of the study.