Magnetic Resonance Imaging-Based Biventricular Pacemaker Upgrade ATTILA R ´ OKA, TAM ´ AS SIMOR,* HAJNALKA V ´ AG ´ O, CSABA MINORICS, GY ¨ ORGY ACS ´ ADY, and B ´ ELA MERKELY From the Department of Cardiovascular Surgery, Semmelweis University, Budapest, and the *Heart Institute, Faculty of Medicine, University of P´ ecs, P´ ecs, Hungary R ´ OKA, A., ET AL.: Magnetic Resonance Imaging-Based Biventricular Pacemaker Upgrade. This report describes a patient with drug refractory severe chronic ischemic heart failure, atrial fibrillation with brady- cardia, and left bundle branch block who had a failed implantation of a biventricular pacemaker because of a high left ventricular pacing threshold. VVI pacemaker implantation had not improved the patient’s condition. MRI-guided biventricular pacemaker upgrade had been performed with a left ventricular epi- cardial lead at the lateral region where a 4-mm thickening during systole had been proven. After 6 months of effective resynchronization, the patient’s functional class improved to NYHA II without further need of hospitalization. (PACE 2004; 27:1011–1013) heart failure, resynchronization, biventricular pacing, MRI Introduction Left bundle branch block (LBBB) worsens the left ventricular (LV) function in patients with con- gestive heart failure. Biventricular pacing is an ef- fective treatment of heart failure associated with LBBB. 1 However, implantation of such a device is demanding, sometimes impossible. After a my- ocardial infarction, scarring of the myocardium near the coronary sinus may raise the pacing threshold. 2 The optimal cardiac resynchronization therapy requires an individual solution in these cases. Case Report A 64-year-old man had an extensive anterior myocardial infarction in 1990. Despite the follow- ing angioplasty and optimal drug treatment, he de- veloped congestive heart failure in 1994, requiring frequent hospitalizations and intermittent intra- venous vasopressor administration. The electro- cardiogram (ECG) showed atrial fibrillation with bradycardia and LBBB with a wide QRS complex (160 ms). The LV ejection fraction was 0.23, the LV end-diastolic and end-systolic diameters were 64/56 mm. The echocardiogram also showed third- degree mitral and tricuspidal insufficiency and LV apical and lateral dyssynchrony. A biventricular pacemaker implantation was attempted in 2003. An optimal coronary sinus lead (Corox LV, Biotronik GmbH & Co., Berlin, Ger- many) position could not be obtained and the pacing threshold was >4 V (0.5 ms), so a right Address for reprints: B´ ela Merkely, M.D., Ph.D., Cardiovascu- lar Center, Dept. of Cardiovascular Surgery, Semmelweis Uni- versity, V´ arosmajor utca 68., Budapest, Hungary, H-1122. Fax: +36-14-58-68-42; e-mail: merkbel@hermes.sote.hu Received December 12, 2003; accepted December 22, 2003. ventricular electrode (Synox 60 BP, Biotronik GmbH & Co.) and a VVI pacemaker (Axios S, Biotronik GmbH & Co.) was implanted. The pa- tient’s condition did not improve after the implan- tation, so a biventricular upgrade with an epicar- dial LV electrode implantation was planned. A detailed viability and function study was necessary to identify the optimal epicardial elec- trode position. After obtaining the patient’s in- formed consent a 1.5 T GE Signa Infinity Echos- peed 1 magnetic resonance imaging (MRI) instru- ment was used. The patient’s spontaneous heart rate was ∼60 beats/min throughout the exam. The pacemaker was temporarily programmed to VVI 30/min, synchronous magnet mode (bipolar pac- ing and sensing). The patient was continuously monitored with pulse oximetry and ECG (with car- bon electrodes). The pacemaker was interrogated before and after the examination without showing any signs of dysfunction. The pacing threshold re- mained unchanged. The FIESTA sequence was used for the cine MRI. 3 Care was taken to avoid any heating ef- fect possibly developing at the tip of the pac- ing lead. The images were edited by MASS 5.0 (Medis, NL 2 ) software. Late enhancement (LE MRI) sequence was used to depict infarcted regions. 4 An extremely dilated LV (end-diastolic volume of 408.4 mL) with a severely decreased systolic LV function (ejection fraction 0.22) and with a severe LV hypertrophy (muscle mass 245 g) was found. Five segments (anteroseptal, inferoseptal, and lat- eral segments in both the middle and apical re- gions of the LV) showed viability (no late enhance- ment and 2–4 mm of wall thickening during sys- tole), while the apex was dyskinetic and the re- maining ten segments were akinetic. The region selected for the epicardial lead implantation was the border of the middle and PACE, Vol. 27 July 2004 1011