Assessment of Atrial Tissue Obtained From Patients Undergoing Heart Surgery and Tissue Banking

Atrial fibrillation (AF), a disorder of heart rhythm, is epidemic in the United States, affecting nearly 3 million people. AF arises in a variety of settings, often in association with other cardiac disease. Demographic and clinical factors can be utilized to profile "at-risk" patients, but the predictive value of such algorithms is low. The reasons for this presumably relate to the fact that these factors are interacting with the tissue substrate in a variable way. In addition, correlations such as these provide no insight into mechanisms associated with the development of AF in patients without other known heart disease, which is commonplace. Over the past decade, techniques have been refined which permit an enormous amount of information relevant to disease mechanisms to be gained from examination of heart tissue. The Cardiovascular Institute has extensive experience with these techniques, and has utilized them to examine other heart disease substrates. In this study, we propose to obtain heart tissue at the time of cardiac surgery which would otherwise be discarded.

Our plan is to examine this tissue and correlate our findings with clinical data. Our hope is that the proposed study will provide insight into atrial physiology, including the molecular mechanisms underlying atrial disease and the potential development of AF.

This will be a prospective tissue bank for atrial tissue. We propose an enrollment of 300 subjects, to take place at UPMC Presbyterian over a 5 year period. Subjects will be recruited from among those patients referred for non-emergent surgery on the heart for standard indications. The patient's medical record will be reviewed and health information recorded that includes but is not limited to demographics, heart disease history, other past medical history, lab work,drug therapy,and all cardiac testing the patient has undergone prior to surgery. Patients undergoing surgery will have residual atrial tissue which would otherwise be discarded (related to cannulation and/or appendectomy). Thus, obtaining this tissue will have no effect on the flow, duration, or outcome of the operative procedure.

Tissue assessment will include:

• Microscopic histology using standard tissue stains; and
• Characterization of gene expression.

Characterization of gene expression will be performed using a multiplicity of techniques which focus on DNA, RNA and proteins produced by the various cells comprising atrial tissue. Expression of a variety of genes known to be important in other cardiac diseases will be analyzed. In addition, expression of novel genes previously not known to be relevant to heart disease may be examined.

Tissue assessment data will be correlated with clinical data including preoperative AF history, demographic information, features of the medical history, details of cardiac structure/function(obtained by examining preoperative tests performed for standard indications), and the incidence of postoperative AF as a first arrhythmia diagnosis.

Inclusion criteria

• 18 years or over
• Referred for heart surgery for standard indication
• Competent to give informed consent

Exclusion criteria

• Inability to give informed consent