PhrenIc Nerve mappinG and Stimulation EP Catheter Study: PING-EP Study

Inclusion Criteria: * Subject is indicated for a cardiac resynchronization therapy-pacemaker or defibrillator (CRT-P/CRT-D) implant, for an upgrading from a previously implanted single/dual chamber pacemaker/implantable cardioverter (ICD) or for system revision requiring repositioning of the transvenous left ventricular (LV) lead * Patient has signed and dated the study-specific Patient Informed Consent form * Subject is at least 18 years of age Exclusion Criteria: * Patient has a previous LV lead implanted not requiring repositioning * Pregnant woman * Patient is enrolled or planning to participate in any concurrent study, which would confound the results of this trial as determined by Medtronic, during the course of this clinical study