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(Circulation. 2003;107:2761.)
© 2003 American Heart Association, Inc.

Images in Cardiovascular Medicine

Electroanatomic Mapping of Cardiac Resynchronization Therapy

Vivek Y. Reddy, MD; Petr Neuzil, MD; Milos Taborsky, MD; Stepan Kralovec;; Lucie Sedivá, MD; Jeremy N. Ruskin, MD

From the Cardiac Arrhythmia Services of Massachusetts General Hospital–Harvard Medical School, Boston, Mass (J.N.R., V.Y.R.), and Na Homolce Hospital, Prague, Czech Republic (P.N., M.T., S.K., L.S.).

Correspondence to Vivek Y. Reddy, MD, Cardiac Arrhythmia Service, Massachusetts General Hospital, 55 Fruit St, GRB 109, Boston, MA 02114. E-mail vreddy{at}partners.org

A 51-year-old man with a history of dilated cardiomyopathy presented with New York Heart Association Class III congestive heart failure. Despite optimal medical management, he continued to experience symptoms consistent with low-output failure: exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea. He was hospitalized 3 times in the previous 4 months for congestive heart failure management. The baseline ECG revealed a left bundle-branch block with a QRS width of 172 ms, and the echocardiogram revealed an ejection fraction of 28%. He was referred to the cardiac arrhythmia service for cardiac resynchronization therapy. A biventricular pacemaker was implanted in the left prepectoral region. A transvenous approach was utilized to position both the standard right-sided leads, and the left ventricular lead was positioned via the coronary sinus (Figure 1).

View larger version (137K): [in this window] [in a new window]   Figure 1. Fluoroscopic position of the cardiac pacing leads. The pacing leads were positioned at the right atrial appendage (RAA), right ventricular apex (RV) and a posterolateral branch of the coronary sinus (LV). The unipolar LV pacing lead was placed by using a transvenous approach after retrogradely engaging the ostium of the coronary sinus with a long sheath.

Two months after implantation of the biventricular pacing system, the patient underwent electroanatomic mapping of both ventricles during an electrophysiological study. Electroanatomic mapping revealed a significant change in the electrical activation pattern during either right ventricular (Figure 2) or biventricular (Figure 3) pacing. As compared with right ventricular pacing alone (Figure 2), biventricular pacing resulted in a concomitant reduction in the width of the QRS complex (Figure 3): 211 ms versus 157 ms, respectively. At 9-month follow-up, the patient experienced a significant improvement of his clinical symptoms (from Class III to Class II) and no hospitalizations for congestive heart failure. A repeat echocardiogram revealed an ejection fraction of 34%.

View larger version (97K): [in this window] [in a new window]   Figure 2. Electrophysiological characterization of standard right ventricular pacing. Top, Endocardial electroanatomic mapping (CARTO, Biosense Inc) of the right and left ventricular chambers was performed during right ventricular pacing at 90 bpm. Both chambers are simultaneously displayed in the left anterior oblique projection. Selected consecutive frames from a wavefront propagation map are shown. The shade of red on the blue background represents the leading edge of the electrical wavefront. The right ventricle and interventricular septum (not seen) are almost completely activated before the rest of the left ventricle is activated. Note that the last area of the ventricle to be activated is the posterolateral base of the left ventricle. Bottom, The 12-lead ECG during right ventricular pacing is shown. The QRS width is 211 ms.

View larger version (98K): [in this window] [in a new window]   Figure 3. Electrophysiological characterization of biventricular pacing. Top, Electroanatomic mapping of both ventricular chambers was repeated during biventricular pacing at 95 bpm. The wavefront propagation maps (left anterior oblique projection) revealed near-synchronous activation of the septal and lateral walls of the left ventricle. Note that the LV pacing lead in the posterolateral venous branch produces earliest activation of the posterolateral base of the left ventricle. Bottom, The 12-lead ECG during biventricular pacing is shown. The QRS width is 157 ms.

In patients with congestive heart failure and significant cardiac conduction system disease, dramatic clinical improvement can be realized by cardiac resynchronization therapy. This case graphically illustrates the consequent electrophysiological changes that occur with this emerging therapeutic modality.

Footnotes

The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.

Circulation encourages readers to submit cardiovascular images to the Circulation Editorial Office, St Luke’s Episcopal Hospital/Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.

This Article Extract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Reddy, V. Y. Articles by Ruskin, J. N. Search for Related Content PubMed PubMed Citation Articles by Reddy, V. Y. Articles by Ruskin, J. N. Related Collections Congestive Pacemaker