Key result
Quadruple-site pacing upgrade improves LVEF by ~10 points in a CRT non-responder.
Why the study?
Some patients with heart failure and depressed LVEF remain symptomatic and dyssynchronous despite optimized biventricular pacing, necessitating alternative pacing strategies.
Case Report (n=1)
No
Upgrading to a quadruple-site ('quadrangular') pacing system can dramatically improve clinical status and promote reverse remodeling in patients who fail to respond to standard biventricular cardiac resynchronization therapy.
A 77-year-old man with a previous history of coronary heart disease, depressed left ventricular ejection fraction (LVEF) of 30%, and permanent atrial fibrillation was referred for decompensated heart failure. A radiofrequency ablation of the atrioventricular junction had been performed because of an uncontrolled high ventricular rate, with implantation of a single-chamber pacemaker with a bipolar lead screwed in the right ventricular apex (ARV, Panel A). Despite optimal medical therapy, he had then been hospitalized several times for congestive heart failure. A biventricular pacemaker had finally been implanted, with an additional unipolar left ventricular lead placed in a posterior-lateral vein. Despite a permanent and optimized biventricular pacing, the patient remained very symptomatic (6-min hall walk test, 110 m), with wide QRS complexes (160 ms) and an LVEF of 30%. Echocardiography showed the persistence of a significant intra-left ventricular dyssynchrony. Two novel pacing leads were then implanted: a bipolar lead screwed in the interventricular septum; a bipolar lead placed via the coronary sinus in an anterior-lateral vein. The two right leads were connected to the right ventricular port through a bipolar Y-connector; the left ventricular anterior-lateral lead was connected to the atrium port; the left ventricular posterior-lateral lead was connected to the left ventricular port. The device (Biotronik Stratos, Berlin, Germany) was programmed in DDDR mode with a minimum atrioventricular delay (15 ms) and no interventricular delay (0 ms), in order to obtain as narrowest QRS complexes as possible (110 ms, Panel B). Nine months after upgrading to quadruple-site pacing, the patient was free from any hospitalization. His clinical status had dramatically improved (6-min hall walk test, 390 m). Echocardiography showed reverse left ventricular remodelling with an increased LVEF of 40%. Three-dimensional speckle-tracking showed a complete left ventricular mechanical resynchronization with simultaneous systolic peaks of the different left ventricular regions (Panel C). Funding to pay the Open Access publication charges for this article was provided by Biotronik, Berlin, Germany.
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Clémenty et al. (2011) conducted a case report in Decompensated heart failure non-responsive to cardiac resynchronization therapy (n=1). Quadruple-site ('quadrangular') pacing vs. Previous biventricular pacing was evaluated on Clinical status, 6-minute walk test, and left ventricular ejection fraction. Upgrading to quadruple-site pacing in a CRT non-responder improved clinical status, increasing 6-minute walk distance from 110 m to 390 m and LVEF from 30% to 40% at 9 months.
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