The purpose of this study is to determine the optimal images of the heart structures which are used to guide AF ablation or BiVenticle and coronary vessels.

'Atrial fibrillation (AF) and ventricular fibrillation are common sustained arrhythmias. The patient will be given an intravenous contrast dye and then hold their breath for 15 seconds while pictures are taken. The equipment used to take the pictures is like an arch that will rotate around the body. As the arch rotates, it will collect the pictures of the heart. These pictures will then be used to compute a three-dimensional image of the heart. The physicians will then continue with the planned procedure. The three-dimensional images will be reconstructed and available for the doctor to view during the case. The images will also be examined after the procedure by the physician.arrythmias of the heart, AF being the most common affecting over 5 million people world wide. While drugs are a first line therapy they can have significant side effects and are often not effective long term. AF ablation and cardiac resynchronization therapy (CRT) are emerging as a viable treatment options for many patients. Both treatments require a detailed knowledge of the anatomy of the heart so that instruments can be safely and accurately navigated within the heart to treat the condition. Detailed anatomical information is limited from 2D fluoroscopy and 3D information from preoperative computed tomography (CT) or electroanatomical mapping have inherent inaccuracies. 3D rotational angiography (C-arm CT) is a technology that will use the x-ray detector system in the EP room to create a 3D image of a section of the heart, such as the left atrium, in the EP treatment room at the onset of the ablation procedure. There are several potential advantages to this imaging technique; As the 3D image is created at the start of the procedure it is a better representation of the heart's anatomy at that time than data acquired days or weeks earlier; it may eliminate the need for a preoperative CT scan for many patients; C-arm CT exposes the patient to a lower radiation dose than a regular cardiac CT scan; and, as the scan is preformed in the EP room the physician has the opportunity to perform secondary scans should he suspect anything has changed during the procedure. The purpose of the research is to determine the optimal imaging protocol for the heart structures needed in cardiac procedures such as AF and CRT. The study will vary several imaging parameters such as contrast injection site, total contrast injected, injection rate, imaging system settings and data reconstruction parameters to determine the most appropriate protocol.'

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Inclusion Criteria:

• Patients undergoing EP diagnostic or therapeutic procedure
• Age > 18 years
• Male or Female
• Weight < 250 lbs
• Not pregnant - women without childbearing potential or women consenting to a pregnancy test
• Able to hold breath for a maximum of 15 seconds
• Sufficient kidney function to support a maximum of 200 cc of contrast in addition to whatever contrast will be given during the EP Procedure
• Creatinine < 1.7 AND cleared by physician prior to case
• Implantable foreign objects acceptable
• NSR or AF
• Patient must sign an informed consent

Exclusion Criteria:

• Patients should not have undergone a CT or CTA scan in the 24 hours prior to this study.
• Creatinine (GFR value) greater than 60