CLINICAL LETTER Exciting things are happening at the ESSA Heart and Vascular Institute and the Pocono Medical Center! We are all proud of the stellar team of professionals who are working very hard to provide the best possible world-class cardiovascular care to the people of Monroe County and beyond. Cardiovascular Medicine is experiencing a rapid evolution and we intend to remain at the cutting edge of technological and clinical innovations so that we can continue to better serve our patients In this second edition of our clinical letter, Drs Jain and Cahill are discussing atrial fibrillation, a common and often debilitating abnormal heart rhythm. The discussions about medical and surgical management and treatment of this heart problem are clearly state-of-the-art. I am sure you will find the information useful and informative. The next edition of our clinical letter will include a discussion on Sudden Cardiac Death by Dr. Vidya Ponnathpur as well as a review on Hypertrophic Cardiomyopathy by myself. We are always glad to receive your comments and suggestions as we strive to serve you better. Best wishes to you! Dr. Nche Zama MD, PhD Clinical Letter - a publication of ESSA Heart and Vascular Institute at PMC Editor - R. Eileen Butz RN, CCRN Questions/Comments? 570.420.5332 ESSA Heart and Vascular Institute at Pocono Medical Center 206 East Brown Street East Stroudsburg PA 18301 POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 1
HIGHLIGHTS OF THE NEW HEART RHYTHM CENTER AT PMC SURGICAL SERVICES Minimally invasive surgical approach (no sternotomy or bypass) to diagnose, treat, and eliminate atrial fibrillation: * Epicardial mapping * Complete surgical block of atrial fib pathways * Excision of left atrial appendage, reducing risk of stroke Bi-ventricular device and lead placement ELECTROPHYSIOLOGY LAB SERVICES Percutaneous vascular access using catheter based technologies : *3-D CARTO Mapping of the heart chambers *AccuNav Intracardiac echocardiography *Full scope of electrophysiology studies of the heart including atrial and ventricular pathway ablation Bi-ventricular device and lead placement (photo of EP lab) To schedule an EP study or to discuss cases with our physicians, call 570.420.5331 POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 2
INDICATIONS FOR IMPLANTABLE CARDIOVERTER/DEFIBRILLATOR (AICD) A patient, at risk for sudden cardiac death based on at least one of the criteria marked below, has been receiving Optimal Medical Therapy and has reasonable expectation of survival with good functioning status for more that 1 year can be considered for this procedure. Criteria For Secondary Prevention Cardiac arrest due to ventricular tachycardia (VT) or ventricular fibrillation (VF) Congenital High risk for VT/VF Spontaneous VT/VF, spontaneous or induced by electrophysiologic study (EPS) Hemodynamically unstable VT Syncope Criteria for Primary Prevention Ejection fraction (EF) <30%. Prior MI>40 days.nyha Class I. LVEF 31-40%. NYHA Class I-III.NSVT, CAD, prior MI, and inducible sustained VT/VF by EPS. LVEF 35%. NYHA Class II-III. History of MI Non ischemic dilated cardiomyopathy (NIDCM) (medically managed for > 3 months) LVEF 35% Criteria for Cardiac Resynchronization Therapy (CRT) EF 35%, NYHA Class III, or ambulatory Class IV QRS duration 120 ms For Primary Prevention ICD - with History of CABG or PCI the waiting period is 90 days. POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 3
Catheter Ablation of Atrial Fibri%ation Dr. Praveer Jain MD FACC Department of Electrophysiology at PMC Atrial fibrillation (AF) is the most frequent sustained arrhythmia affecting human beings. The estimated prevalence of AF in the general population is 0.4 to 1.0 %, increasing with age to 8% among those 80 years or older. AF is associated with increased long-term risk of stroke, heart failure, and all cause mortality. Management of patients with AF involves three objectives: prevention of thromboembolism, rate control, and restoration and maintenance of sinus rhythm. Traditionally, restoration and maintenance of sinus rhythm is achieved with cardioversion and use of anti-arrhythmic therapy. However, antiarrhythmic agents have limited efficacy with potential for serious side effects. Even though the Atrial Fibrillation Followup Investigation of Rhythm Management (AFFIRM) trial suggested an equivalent outcome for pharmacological rate control and rhythm control strategies, further analysis revealed that sinus rhythm was associated with a 47% lower risk of death, whereas the use of antiarrhythmic therapy was associated with a 49% increased risk of mortality. Thus, this trial highlighted the fact that the benefits of sinus rhythm can be negated by the harmful effects of antiarrhythmic agents. Therefore, restoration and maintenance of sinus rhythm may be of benefit if it can be achieved without the use of anti-arrhythmic agents Pathophysiology of Atrial Fibrillation AF originates from pulmonary veins (PV) as the primary trigger in 94% of the patients. These triggers interact with the atrial substrate by conduction across discrete muscle bundles connecting the PV s with the left atrium; radiofrequency ablation of these muscle bundles effectively isolated the PV s from the left atrium. Common non-pv triggers include superior vena cava, posterior left atrial wall, crista terminalis, coronary sinus ostium, ligament of Marshall, and interatrial septum. Focal ablation at these sites after careful mapping can be curative. Radiofrequency Ablation (RFA) Current indication for curative ablation of AF is limited to patients who remain symptomatic despite the use of antiarrhythmic agents. The group in which PV isolation alone achieves the greatest benefit consists of patients with short episodes of AF (less than 24 hours) who have no evidence of structural heart disease, and have near normal left atrial size. As AF becomes more established (persistent or permanent AF), the ability of PV isolation alone to cure AF is attenuated. However, indications for RFA as a primary strategy to establish sinus rhythm continue to evolve at a rapid pace. (continued on p5) POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 4
CATHETER ABLATION OF ATRIAL FIBRILLATION (continued from p4) RFA of AF may be approached in many different ways, but we favor the approach described here. Once the patient has been selected for the procedure, a CT scan of the heart is obtained to assess pulmonary venous architecture. Several days prior to the procedure, warfarin is discontinued, and one day prior to the procedure, heparin therapy is initiated. We routinely perform trans-esophageal echocardiogram prior to the procedure to rule out left atrial appendage thrombus, an absolute contraindication to trans-septal puncture. On the morning of the procedure, heparin is discontinued. Several venous sheaths and diagnostic catheters are then inserted. Utilizing fluoroscopy and intra-cardiac echocardiogram, two separate trans-septal punctures are performed, and the patient is fully re-anticoagulated. Left atrial and pulmonary venous architecture are then defined utilizing CARTO three dimensional mapping system. Each pulmonary venous ostium is then defined using the Lasso circumferential mapping catheter, and the vein is isolated using an externally irrigated cooled tip ablation catheter. The end-point for the ablation is documentation of entrance and exit block at each pulmonary venous site. Additional measures such as ablation of complex fractionated atrial electrograms, linear ablation, ablation of autonomic targets, right atrial flutter ablation, and ablation of non-pv triggers are undertaken only when considered clinically appropriate. Post-procedure, after an interval for sheath removal, patients are re-anticoagulated and prior antiarrhythmic therapy is resumed. Patients are then closely followed clinically and utilizing event recorders. A followup CT scan of the heart is obtained to rule out PV stenosis. If the patient maintains sinus rhythm for several months, antiarrhythmic therapy is discontinued, followed by discontinuation of warfarin therapy. CARTO mapping system : red areas show locations of ablation Close examination of the Lasso catheter (continued on p6) POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 5
ESSA HEART AND VASCULAR INSTITUTE APR/MAY/JUNE 2009 CATHETER ABLATION OF ATRIAL FIBRILLATION (continued from p5) Results and Complications The success rate of ablation when PV isolation is used as an end-point has been remarkably similar in reports from a number of groups; with 60-70% of patients with paroxysmal AF maintaining sinus rhythm without antiarrhythmic therapy. The success rate is much lower among patients with chronic AF, not exceeding 30-40%. A significant proportion of patients require a second procedure to achieve cure. Procedural complications included adverse events associated with any cardiac catheterization procedure. Complications specific to AF ablation include the following: PV stenosis Current strategies, however, avoid delivering energy within the PV s, and include target areas outside the veins to isolate the ostia from the remainder of the left atrial tissue. Embolic stroke (1-5%) Prevented by aggressive anticoagulation during the procedure. Atrioesophageal fistula A rare complication but with uniformly fatal outcome, prevented with less aggressive ablation along the posterior left atrial wall. Le* atrial flutter due to macroreentrant circuits, amenable to ablation. Future Directions Technology for AF ablation continues to evolve rapidly. Several clinical trials are underway, seeking to define the role of AF ablation in clinical practice. Over the next several years, the indication for AF ablation will likely expand, procedural time will be reduced, success rates will improve, while the safety of the procedure will be enhanced. Atrial Fibrillation Dr. Anne T. Cahill MD Department of Cardiothoracic Surgery at PMC There are 350,000 new cases of atrial fibrillation annually, in the US alone. Patients with atrial fibrillation have a statistically significant shortened life expectancy and higher risk of morbidity, particularly stroke. Rate control alone does not ameliorate stroke risk and often does not control symptoms. Thirty percent of patients in afib remain symptomatic, likely secondary to decreased cardiac output, with an ejection fraction reduction by 30%. The risk of stroke for these patients is 65 to 126% higher than in patients without atrial fibrillation. Because of this elevated stroke risk, Coumadin is recommended for the POCONO MEDICAL CENTER www.poconohealthsystem.org (continued on p7) PAGE 6
ATRIAL FIBRILLATION (continued from p6) rate-controlled patient remaining in atrial fibrillation. Coumadin inherently carries an annual stroke risk rate of 3% to 5%, related to bleeding or thrombosis. Ninety five percent of cardiac emboli arise in the left atrial appendage. This is one significant advantage of the surgical ablation of atrial fibrillation which includes ligation and removal of the appendage. Indications for surgical ablation for atrial fibrillation includes patients who remain symptomatic with the use of anti arrhythmic medications or those who do not tolerate the medication. There is also a role for concomitant treatment for those having open heart surgery for another indication: coronary bypass, mitral valve, or aortic valve. The surgical ablation procedure is a minimally invasive bilateral VATS thoracotomy using irrigated radiofrequency energy. We use a lighted navigator tissue dissector followed by placement of the jaws of the Gemini device around the pulmonary veins. Tissue impedence is measured by the device which delivers the appropriate amount of energy for that tissue thickness. Epicardial mapping is used to identify the trigger points by vagal stimulation. If these trigger points are not included in the pulmonary veins (the ligament of marshall on the left side for example) they are ablated individually. Post ablation mapping confirms block of the atrial fibrillation pathways. Surgical ablation has the advantage of not only pulmonary vein isolation for cure, but also complete epicardial mapping and ablation of the autonomic ganglia. The pulmonary vein isolation is performed with a complete transmural technique. The Gemini device allows us to confirm a transmural lesion (through and through muscle) without the risk of esophageal or neighboring tissue injury. Post procedure mapping will confirm the success of the lesion set prior to closing. (continued on p8) POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 7
ESSA HEART AND VASCULAR INSTITUTE APR/MAY/JUNE 2009 ATRIAL FIBRILLATION (continued from p7) Patients may be discharged 24-72 hours post procedure when pain is adequately controlled. They can resume full activity in about 2 weeks. The complete cure is not evident for 2-6 months yet most patients are discharged in normal sinus rhythm. They need to continue anti arrhythmic medication and anti coagulation for 6 months until the surgical scar is complete. Patients may require cardioversion within the six months until the scar is complete. The cure rate is 72-94% for paroxysmal atrial fibrillation with potential elimination of stroke risk with or without cure secondary to excision of the left atrial appendage. The new Heart Rhythm Center at PMC now provides both surgical and percutaneous ablation procedures to treat arrhythmias. Our surgeons and cardiologists work closely together to provide the patient with the most current diagnostic and interventional procedures which best meets their individual care needs. For more information on the Heart Rhythm Center please contact Dr. Anne T. Cahill or Dr Praveer Jain at 570-420-5331 ESSA s Heart and Vascular Institute welcomes new cardiologists Devendra K. Amin, MD Arthur Meltzer, MD COMING IN OUR NEXT ISSUE: Dr. Vidya Ponnathpur MD, FACC Sudden Cardiac Death Dr. Nche Zama MD, PhD Hypertrophic Cardiomyopathy POCONO MEDICAL CENTER www.poconohealthsystem.org PAGE 8