This study is performed to assess if PET-MR imaging can improve treatment of patients with irregular heart rate and heart failure. Heart failure occurs when the heart muscle is too weak to do his work correctly. Irregular heart rate can be related to numerous diseases. One category of irregular heart rate is called ventricular arrhythmia. It is often seen in patients who have had a heart attack. This type of arrhythmia can be dangerous and can cause sudden death. To prevent these arrhythmias, doctors can perform procedures that burn the source of arrhythmia in the heart muscle. This is called ablation. Unfortunately, ablation does not fix the problem in 100% of patients and some will still have the arrhythmia requiring repeated procedure. The purpose of this study is to find new ways of guiding the doctors performing ablation, hoping to improve the success rate of the procedure.

Healthy Volunteers

Inclusion Criteria:

• Subjects must be ≥21 and ≤80 years of age;
• Subjects must provide informed consent prior to study procedures;

Exclusion Criteria:

• Known structural heart disease (e.g. myocardial infarction);
• History of ventricular arrhythmia;
• Any contraindication to MRI and/or PET, including:
• Subjects with life vest;
• Subjects with implanted heart device (e.g. ICD, Pacemaker);
• Subjects with metallic fragment or foreign body;
• Subjects with other form of devices or prosthesis that are not MRI compatible, such as insulin pump, joint replacement, hearing aid, cochlear implant, permanent contraceptive devices, etc.;
• Claustrophobia;
• Relative or absolute contraindication to Dotarem contrast:
• history of renal disease including acute or chronic severe renal insufficiency (glomerular filtration rate <60 mL/min/1.73m2);
• a history of diabetes mellitus, systemic lupus, multiple myeloma, nephrogenic systemic fibrosis, and other co-morbidities;
• History of hypersensitive reactions to Dotarem and/or gadolinium contrast agent
• Any clinically significant acute or unstable physical or psychological disease, judged by the investigators based on medical history or screening physical examination, to be incompatible with the study;
• Any physical or psychological disease judged by the investigators to be incompatible with the study, based on medical history or screening physical examination
• Radiation exposure exceeds current Radiology Department guidelines (i.e. 50 mSv in the prior 12 months);
• Female subjects only: Positive serum and/or urine pregnancy test, or lactating, or possibility of pregnancy cannot be ruled out prior to dosing;
• Inability to provide written informed consent;

Arrhythmia Subjects:

Inclusion criteria

• Subjects must be ≥21 and ≤80 years of age;
• Subjects must provide informed consent prior to study procedures;
• History of scar-mediated ventricular arrhythmia scheduled for invasive EAM-guided catheter ablation for clinical care

Exclusion criteria

• Any contraindication to MRI and/or PET, including:
• Subjects with life vest;
• Subjects with implanted heart device (e.g. ICD, Pacemaker);
• Subjects with metallic fragment or foreign body;
• Subjects with other form of devices or prosthesis that are not MRI compatible, such as insulin pump, joint replacement, hearing aid, cochlear implant, permanent contraceptive devices, etc.;
• Claustrophobia;
• Relative or absolute contraindication to Dotarem contrast:
• history of renal disease including acute or chronic severe renal insufficiency (glomerular filtration rate <60 mL/min/1.73m2);
• history of diabetes mellitus, systemic lupus, multiple myeloma, nephrogenic systemic fibrosis, and other co-morbidities;
• History of hypersensitive reactions to Dotarem and/or gadolinium contrast agent;Any clinically significant acute or unstable physical or psychological disease, judged by the investigators based on medical history or screening physical examination, to be incompatible with the study;
• Any physical or psychological disease judged by the investigators to be incompatible with the study, based on medical history or screening physical examination
• Radiation exposure exceeds current Radiology Department guidelines (i.e. 50 mSv in the prior 12 months);
• Female subjects only: Positive serum and/or urine pregnancy test, or lactating, or possibility of pregnancy cannot be ruled out prior to dosing;
• Inability to provide written informed consent;