Ventricular Wall Motion Characterization

Inclusion Criteria: * Be in sinus rhythm * Have the ability to provide informed consent for study participation and be willing and able to comply with the Clinical Investigational Plan described evaluations * Be undergoing mapping and ablation that requires left heart access for either ventricular tachycardia (VT) or atrial fibrillation (AF) according to HRS (Heart Rhythm Society)/ESC (European Society of Cardiology)/German National guidelines. The patient needs to have at least one of the following indications for left heart mapping and ablation to be included in the study: a) Symptomatic sustained monomorphic VT (SMVT), or b) Frequent PVCs, non-sustained VT, or VT that is presumed to cause ventricular dysfunction, or c) Bundle branch reentrant or interfascicular VTs, or d) Symptomatic AF with indication for ablation per current HRS/ESC/German National guidelines in a patient who is either 1) refractory or intolerant to at least one Class 1 or Class 3 antiarrhythmic medication, or 2) unable/unwilling to take antiarrhythmic drug therapy and chooses ablation as the first line of therapy Exclusion Criteria: * Have permanent AF * Exhibit Cheyne-Stokes respiration * Have a recent myocardial infarction within 40 days prior to enrollment * Have undergone cardiac surgery or coronary revascularization procedure within 3 months prior to enrollment or be scheduled for such procedures * Have had a recent CVA or TIA within 3 months prior to enrollment * Be less than 18 years of age * Be pregnant * Be currently participating in any other clinical investigation