New Insight Into Left Ventricular Reverse Remodeling
Biventricular pacing has been consistently shown to improve symptoms and exercise capacity in patients with advanced heart failure and wide QRS complexes. Recent data have shown that biventricular pacing has the propensity to reduce left ventricular volume, a condition referred to as reverse remodeling. Since the author's initial description of successful left ventricular reverse remodeling after biventricular pacing therapy, data from multicenter trials have grown and consistently support the observation. In addition to the volumetric change, there was also progressive improvement of left ventricular systolic function and clinical status. The author's subsequent data also illustrated that the benefits on reverse remodeling and left ventricular systolic function were pacing dependent and disappeared gradually when pacing was withdrawn. With the use of tissue Doppler imaging, a substantial proportion of patients were found who had mechanical delay in the free wall. During biventricular pacing, all the segments were homogenously delayed resulting in a late, albeit synchronous, systolic contraction.
Cardiac resynchronization therapy in the form of biventricular pacing is a recent technologic advance as an adjunctive nonpharmacologic therapy for patients with advanced congestive heart failure with electromechanical delay. Cumulative experience from single or multicenter studies has consistently shown that the therapy improves hemodynamic status acutely, as well as heart failure symptoms, exercise capacity, quality of life, and systolic function after 3-6 months of therapy. Recently, the reverse remodeling effect of biventricular pacing was also observed, as illustrated by the reduction of left ventricular (LV) size after treatment for at least 3 months. This favorable change after the therapy is likely to contribute to the improvement of cardiac function and hence clinical status. The mechanisms of benefit provided by this new modality of treatment were not fully understood until recently, following the advent of new tools that directly assess regional synchronicity, such as tissue Doppler imaging (TDI). This review focuses on the role of biventricular pacing on LV reverse remodeling and reveals the mechanisms of benefit through studying the regional wall motion of the heart.
Biventricular pacing has been consistently shown to improve symptoms and exercise capacity in patients with advanced heart failure and wide QRS complexes. Recent data have shown that biventricular pacing has the propensity to reduce left ventricular volume, a condition referred to as reverse remodeling. Since the author's initial description of successful left ventricular reverse remodeling after biventricular pacing therapy, data from multicenter trials have grown and consistently support the observation. In addition to the volumetric change, there was also progressive improvement of left ventricular systolic function and clinical status. The author's subsequent data also illustrated that the benefits on reverse remodeling and left ventricular systolic function were pacing dependent and disappeared gradually when pacing was withdrawn. With the use of tissue Doppler imaging, a substantial proportion of patients were found who had mechanical delay in the free wall. During biventricular pacing, all the segments were homogenously delayed resulting in a late, albeit synchronous, systolic contraction.
Cardiac resynchronization therapy in the form of biventricular pacing is a recent technologic advance as an adjunctive nonpharmacologic therapy for patients with advanced congestive heart failure with electromechanical delay. Cumulative experience from single or multicenter studies has consistently shown that the therapy improves hemodynamic status acutely, as well as heart failure symptoms, exercise capacity, quality of life, and systolic function after 3-6 months of therapy. Recently, the reverse remodeling effect of biventricular pacing was also observed, as illustrated by the reduction of left ventricular (LV) size after treatment for at least 3 months. This favorable change after the therapy is likely to contribute to the improvement of cardiac function and hence clinical status. The mechanisms of benefit provided by this new modality of treatment were not fully understood until recently, following the advent of new tools that directly assess regional synchronicity, such as tissue Doppler imaging (TDI). This review focuses on the role of biventricular pacing on LV reverse remodeling and reveals the mechanisms of benefit through studying the regional wall motion of the heart.