Cardiac Resynchronization Therapy
Cardiac Resynchronization Therapy
Cardiac resynchronization therapy (CRT) is currently an established device therapy for heart failure (HF) patients. Cumulated knowledge on the pathophysiological mechanisms, implantation techniques, advancement of device-based technologies, and clinical trial experience has impacted on this evolving therapy significantly in the last few years. This article will address the updated CRT guideline and potentially new indications of CRT such as patients with New York Heart Association Class I, normal QRS duration, and non-HF patients with pacing indications. Furthermore, important but unresolved issues will also be discussed which include the impact of QRS morphology and QRS duration on CRT response, new approaches for placement of left ventricular (LV) lead, multisite LV pacing, and the role of HF disease monitoring program.
With the adoption of guidelines for cardiac resynchronization therapy (CRT) for heart failure (HF) patients since early of the millennium, a plethora of research in the field continues which has addressed many important aspects of the therapy. As a result of the research work, the mechanisms that mediated the benefits of CRT are revealed (Figure 1). Furthermore, some researchers have contributed to the core knowledge of updated guidelines, while others have provided practical information on how to improve the quality and treatment efficacy for patients receiving CRT, or quest for evolving or new treatment indications by the use of CRT. The current article has summarized these issues based on key research discoveries or results in the last few years (Table 1).
(Enlarge Image)
Figure 1.
Mechanisms of deterioration of cardiac function in heart failure patients with prolongation of QRS complex (especially in the form of left bundle branch block) resulting in electromechanical delay. Electrical disturbances induce mechanical dyssynchrony at different levels: atrioventricular dyssynchrony (1, 2), interventricular dyssynchrony (3), intraventricular dyssynchrony (4), as well as mitral regurgitation (5). As a result of these abnormalities, there is ineffective contraction with rocking motion of the left ventricle during systole, elevation of filling pressure, left ventricular pressure, and overload overload, as well as decreased cardiac output. Cardiac resynchronization therapy improves and reverses these abnormalities result in left ventricular reverse remodelling and reduction of mitral regurgitation.
Abstract and Introduction
Abstract
Cardiac resynchronization therapy (CRT) is currently an established device therapy for heart failure (HF) patients. Cumulated knowledge on the pathophysiological mechanisms, implantation techniques, advancement of device-based technologies, and clinical trial experience has impacted on this evolving therapy significantly in the last few years. This article will address the updated CRT guideline and potentially new indications of CRT such as patients with New York Heart Association Class I, normal QRS duration, and non-HF patients with pacing indications. Furthermore, important but unresolved issues will also be discussed which include the impact of QRS morphology and QRS duration on CRT response, new approaches for placement of left ventricular (LV) lead, multisite LV pacing, and the role of HF disease monitoring program.
Introduction
With the adoption of guidelines for cardiac resynchronization therapy (CRT) for heart failure (HF) patients since early of the millennium, a plethora of research in the field continues which has addressed many important aspects of the therapy. As a result of the research work, the mechanisms that mediated the benefits of CRT are revealed (Figure 1). Furthermore, some researchers have contributed to the core knowledge of updated guidelines, while others have provided practical information on how to improve the quality and treatment efficacy for patients receiving CRT, or quest for evolving or new treatment indications by the use of CRT. The current article has summarized these issues based on key research discoveries or results in the last few years (Table 1).
(Enlarge Image)
Figure 1.
Mechanisms of deterioration of cardiac function in heart failure patients with prolongation of QRS complex (especially in the form of left bundle branch block) resulting in electromechanical delay. Electrical disturbances induce mechanical dyssynchrony at different levels: atrioventricular dyssynchrony (1, 2), interventricular dyssynchrony (3), intraventricular dyssynchrony (4), as well as mitral regurgitation (5). As a result of these abnormalities, there is ineffective contraction with rocking motion of the left ventricle during systole, elevation of filling pressure, left ventricular pressure, and overload overload, as well as decreased cardiac output. Cardiac resynchronization therapy improves and reverses these abnormalities result in left ventricular reverse remodelling and reduction of mitral regurgitation.
