PracticeUpdate Cardiology March 2019

EDITOR’S PICKS 14

His Resynchronization vs Biventricular Pacing in Patients With Heart Failure and Left Bundle Branch Block Journal of the American College of Cardiology

Take-home message • In this single-center, prospective study, the use of temporary His bundle pacing (HBP) was compared with conventional biventricular (BVP) cardiac resynchronization therapy (CRT) in 17 patients with heart failure and left bundle branch block for whom complete data were available. HBP resulted in greater reductions in left ventricular activation time, left ven- tricular dyssynchrony index, and QRS duration compared with BVP. Additionally, the acute hemodynamic response was greater with HBP compared with BVP. • Although this was a very small study, the findings suggest that HBP may be superior to BVP. Further study is needed. F or my top story of 2018, I wrote, “The success of His bundle pacing represents the top 2018 story because it restores normal physiologic electrical ventricular depolarization with a single lead even in the presence of most bundle branch blocks, and it eliminates the need for left ventricular pacing and the potential for a pacing-induced cardiomyopathy…I anticipate it will replace CRT. As such, it becomes a therapeutic paradigm shift in the world of pacing.” The present study offers proof to support that statement. The authors performed a head-to-head crossover comparison between His bundle pacing and conventional biventricular CRT, measuring effects on ventricular activation and acute hemody- namic function in heart failure patients with left bundle branch block referred for conventional biventricular CRT placement. In 17 of 23 patients in whom complete data were obtained, His bundle pacing provided better resynchronization than biventricular pacing, with greater reductions in QRS duration (18.6 ms), left ventricular activation time (26 ms), and left ven- tricular dyssynchrony index (11.2 ms). His bundle pacing also produced a greater acute hemodynamic response (4.6 mmHg). The incremental activation time reduction with His bundle pac- ing over biventricular pacing correlated with the incremental hemodynamic improvement. We now need a prospective randomized trial of His bundle pacing versus CRT using clinical outcomes as the primary end- point. I have no doubt that His bundle pacing will result in reduced MACE compared with CRT. His bundle pacing is also less expensive, less complicated, and, once technical inser- tion and leads are optimized, will be the procedure of choice for most patients with LBBB and prolonged QRS complex, as well as the optimal pacing site for virtually all ventricular pac- ing leads. COMMENT By Douglas P. Zipes MD

Abstract BACKGROUND His bundle pacing is a new method for delivering cardiac resynchronization therapy (CRT). OBJECTIVES The authors performed a head-to-head, high-precision, acute crossover comparison between His bundle pacing and conventional biventricular CRT, measuring effects on ventricular activation and acute hemodynamic function. METHODS Patients with heart failure and left bundle branch block referred for conventional biventricular CRT were recruited. Using noninvasive epicardial electrocardiographic imaging, the authors identified patients in whom His bundle pacing shortened left ventricular activation time. In these patients, the authors compared the hemodynamic effects of His bundle pacing against biventricular pacing using a high-multiple repeated alternation protocol to minimize the effect of noise, as well as comparing effects on ventricular activation. RESULTS In 18 of 23 patients, left ventricular activation time was significantly shortened by His bundle pacing. Seventeen patients had a complete elec- tromechanical dataset. In them, His bundle pacing was more effective at delivering ventricular resynchronization than biventricular pacing: greater reduction in QRS duration (−18.6 ms; 95% confidence interval [CI]: −31.6 to −5.7 ms; p = 0.007), left ventricular activation time (−26 ms; 95% CI: −41 to −21 ms; p = 0.002), and left ventricular dyssynchrony index (−11.2 ms; 95% CI: −16.8 to −5.6 ms; p < 0.001). His bundle pacing also produced a greater acute hemodynamic response (4.6 mm Hg; 95% CI: 0.2 to 9.1 mm Hg; p = 0.04). The incremental activation time reduction with His bundle pacing over biventricular pacing correlated with the incremental hemo- dynamic improvement with His bundle pacing over biventricular pacing (R = 0.70; p = 0.04). CONCLUSIONS His resynchronization delivers better ventricular resynchro- nization, and greater improvement in hemodynamic parameters, than biventricular pacing. His Resynchronization Versus Biventricular Pacing in Patients With Heart Failure and Left Bundle Branch Block. J Am Coll Cardiol 2018 Dec 10;72(24)3112–3122, AD Arnold, MJ Shun-Shin, D Keene, et al. www.practiceupdate.com/c/77398

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