Subjects eligible for this study have an irregular heartbeat called atrial fibrillation
(AF)and who are scheduled for a procedure that involves applying electrical energy in your
pulmonary veins, which is usually the site where this abnormal rhythm begins, or pulmonary
We will examine the size and function of the left atrium (one of the 4 chambers of your
heart) and the pulmonary veins before and after your ablation. This will be done by getting
extra measurements during tests you will be having done which are ICE (intra cardiac
echocardiography), TEE (transesophageal echocardiography) and CT scan (computed tomography),
and drawing some blood samples.
The purpose of getting these extra measurements and blood samples is:
1. to see whether TEE measurements done before your ablation can tell us if your atrial
fibrillation may come back after you ablation;
2. to see if TEE measurements look different before and after your ablation;
3. to see if a blood test can tell us if your atrial fibrillation may come back after your
4. to look at how often pulmonary vein narrowing is found by TEE compared to how often it
is found by CT scan.
During the clinically indicated tests the doctor has ordered (TEE, ICE, CT scan), there will
be additional measurements taken as a part of this research. This means that the TEE exam
will last an additional 10-15 minutes, and the ICE procedure will last an additional 5-10
minutes. There is no additional time needed for the CT scan. In addition, we will be drawing
20 cc of blood (approximately four teaspoons).
The regularly scheduled follow up visit is usually three months after your ablation, we will
again be getting some extra measurements from the TEE and CT scan. This will add about 10-15
minutes to the TEE test, but no additional time will be needed for the CT scan. In addition,
we will be drawing 10 cc of blood drawn (approximately two teaspoons). A
ventilation-perfusion scan of the lungs will also be performed as part of standard clinical
care if significant PV stenosis is found by CT and/or TEE.
1. Examine the structure and function of the left atrium, left atrial appendage and
pulmonary veins before and after ablation.
2. Compare the findings of transesophageal echo with those from intracardiac echo.
3. Detect the incidence of pulmonary vein stenosis assessed by transesophageal echo
compared to computed tomography.
4. Assess for physiological predictors for recurrence of atrial fibrillation based on
5. Determine whether biological markers such as B-type natriuretic peptide or C-reactive
protein predict recurrence of atrial fibrillation.
6. Assess if markers of coagulation such as D-dimer and prothrombin factor 1.2 are
increased in atrial fibrillation and could predict thromboembolic risk.
General Procedures Prior to ablation, blood will be drawn for measuring c-reactive protein,
brain natriuretic polypeptide, D-dimer and prothrombin fragment 1.2. A transesopahegeal
echocardiogram and an intracardiac echocardiogram will be performed. Then following sterile
techniques, standard catheters will be passed through veins and positioned into the heart
using X-ray guidance, and will cross the wall that divides the upper chambers of the heart
so that the left atrium can be reached.The catheters will be used to trigger sites that
originate the anomalous rhythm and once these are identified the generator will deliver
radiofrequency energy to destroy the areas that cause irregular beats. After ablation
follow-up visits will be done at one, three, six and twelve months. During that time several
tests such as electrocardiograms, 24 hour Holter recording, computed tomography of the
heart, transesophageal echocardiogram and repeated blood drawing to measure c-reactive
protein, brain natriuretic peptide, D-dimer and prothrombin fragment 1.2 will be done.
- Persistent or paroxysmal AF, resistanct to medical therapy
- Normal renal function (creatininine <1.5
- Unable or unwilling to give informed consent
- History of esophageal diseases, such as stricture, vaices or cancer
- Inability to swallow TEE probe
- Severe mitral stenosis
- Severe mitral reguritation
- Cardiothoracic surgery within 6 months