EP Lab Digest - March 2008 - (Page 6)

6 COVER STORY MARCH 2008 ECG 101: THE CASE OF A DIZZY PATIENT WITH A LEFT BUNDLE BRANCH BLOCK Continued from cover Due to our concerns about his presentation, an echocardiogram and a perfusion scan were performed. The left ventricular ejection fraction was 38% without evidence for valvular heart disease. The left ventricle was mildly dilated but not hypertrophied. A rest and exercise Sestamibi scan showed no perfusion defect. He was able to exercise to stage 4 of the Bruce protocol without any ST-T changes. A Holter monitor showed asymptomatic short episodes of Wenckebach block at heart rates at 100 bpm. What would you do next? Discussion Patients who complain of episodic dizziness, palpitations and syncope are commonly referred for electrophysiology evaluation. The proper evaluation can be challenging but, in this case, an aggressive approach was taken due to his symptoms, the presence of left bundle branch block, and evidence for structural heart disease, which was probably related to non-ischemic cardiomyopathy. A proper evaluation of symptoms in patients with LV dysfunction is important, as these may represent potentially serious and recurrent arrhythmias or even lead to cardiovascular collapse and ultimately death. It was not completely clear if this patient had syncope or not, but he did have recurrent, debilitating dizziness that compelled us to proceed further. We did not have an explanation for his syncope or dizziness despite the asymptomatic Wenckebach on the Holter monitor. Even though an implantable loop recorder may document a symptomatic arrhythmia, it was not recommended as this patient was at risk of having a serious, life-threatening arrhythmia. Similarly, proceeding directly to tilt table testing was not recommended. For patients with a left bundle branch block and impaired ventricular function, cardiac electrophysiology testing is warranted, especially if there is no immediate need to proceed to defibrillator implantation. In this case, as episodes of dizziness were distributed over a six-month period and the most recent episode was a few weeks before presenting to the clinic, immediate hospitalization was not recommended. Instead, he was scheduled for outpatient cardiac electrophysiology testing. In recent times, electrophysiologists often forgo electrophysiology testing for patients with syncope who have evidence for impaired ventricular function. When there is a presence of structural A proper evaluation of symptoms in patients with LV dysfunction is important, as these may represent potentially serious and recurrent arrhythmias or even lead to cardiovascular collapse and ultimately death. What is the Wenckebach phenomenon? Wenckebach block is second degree block in which there is progressive lengthening in the PR interval (with a constant PP interval) before a blocked beat and then the cycle begins again. The location of block is generally in the AV node, but occasionally Wenckebach block occurs in the His bundle (intra-Hisian) or below the His bundle (infra-Hisian). heart disease with a low ejection fraction, based on accepted criteria, such patients may be directly implanted with a cardioverter defibrillator (ICD). See ECG 101: THE CASE OF A DIZZY PATIENT WITH A LEFT BUNDLE BRANCH BLOCK page 8 About the University of Iowa Hospitals and Clinics: University of Iowa Hospitals and Clinics, located in Iowa City, Iowa, is a comprehensive academic medical center. When the first University of Iowa Hospital opened on January 11, 1898, there were 50 beds; today UI Hospitals and Clinics is a 680-bed comprehensive academic medical center and regional referral center, committed to providing patient-focused care in an environment devoted to innovative care, excellent service, and exceptional outcomes. Hospital Recognition: • UI Hospitals and Clinics has been consistently recognized by U.S.News & World Report as one of the nation's best hospitals, with many of its clinical specialties ranked among the best. • UI Hospitals and Clinics was the first in the state to receive the Magnet designation for excellence in nursing practice from the American Nurses Credentialing Center. • University of Iowa Children's Hospital was named one of the top 20 children’s hospitals in the U.S. by Child magazine. • More than 180 of our physicians are included in the Best Doctors in America database. UI Heart and Vascular Care was named a Blue Distinction Center by Wellmark Blue Cross Blue Shield of Iowa. • UI Stroke Center earned the Gold Seal of Approval™ from The Joint Commission for Primary Stroke Centers. Hospital Firsts: • First medical center to provide definite evidence that coronary artery occlusion produces heart damage and electrocardiographic abnormalities • First hospital to demonstrate that a reduction in blood cholesterol produces improvement in atherosclerotic plaques • First hospital in Iowa, and one of the nation’s first, to perform echocardiography as a standard clinical diagnostic test • First hospital in Iowa with a Cardiovascular Research Center that is now recognized worldwide for its significant research advances For more information, please visit: http://www.uihealthcare.com/uihospitalsandclinics/ http://www.uihealthcare.com/uihospitalsandclinics/

Table of Contents Feed for the Digital Edition of EP Lab Digest - March 2008

EP Lab Digest - March 2008 ECG 101: The Case of a Dizzy Patient with a Left Bundle Branch Block Delayed Defibrillation: Research and Results Interview with Paul S. Chan, MD Contents Letter from the Editor Spotlight Interview: St. Joseph’s Hospital Health Center Parent Heart Watch from 36,000 Feet… Perspectives from the Annual Leadership Conference Clinical Trial Overview: 2008 Are MRI-Safe Pacemakers and Leads on the Horizon? Q & A with J. Rod Gimbel, MD Navigating Tortuous Coronary Sinus Anatomy Using a Bipolar Lead Email Discussion Group: March 2008 Guidelines on ECG Interpretation Spotlight Interview Update: What Have We Learned? The Value of Educating Staff Events Calendar Industry News and Products Classifieds Advertisers Index In Memoriam

EP Lab Digest - March 2008

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