Ultra-High Frequency - Electrocardiogram (UHF-ECG) for the Diagnosis of Ventricular Electrical Dyssynchrony (VED)

This study is evaluating a new type of electrocardiogram (ECG) technology called Ultra-High Frequency ECG (UHF-ECG) to see if it can better detect abnormal electrical patterns in the heart, particularly for people who need a pacemaker or a device to help the heart beat in sync. **You may be eligible if...** - You are an adult scheduled to receive a pacemaker for a slow heart rate, OR - You have heart failure and are scheduled to receive a cardiac resynchronization therapy (CRT) device - Your heart condition fits specific criteria regarding the electrical pattern (QRS duration) on a standard ECG - You are willing to comply with study requirements **You may NOT be eligible if...** - You have a complete third-degree heart block without a reliable heart rhythm - You already have a pacemaker or defibrillator - You have a skin condition or allergy that makes it hard to attach ECG pads - You are pregnant - You are enrolled in a conflicting device study Talk to your doctor to see if this trial is right for you.