Heart failure is a complex disease and the
Heart failure is a complex disease and the status of each patient is highly heterogeneous; therefore, nominal manufacturer-delivered device settings may not be optimal for all patients who receive CRT implantation. A growing body of evidence suggests hemodynamic and clinical status benefits associated with optimization of atrioventricular (AV) and VV delays [13–16]. However, alteration of the atrial and ventricular morphologies over time because of reverse remodeling may also influence these parameters, which may have been optimal at the time of ikk pathway [17,18]. The optimization methods preferred by Japanese physicians and the duration between repeated optimizations are unknown, and there is no general consensus among physicians about the need for routine optimization. The goal of this study was to collect information on the current status of CRT device optimization in Japan.
Methods A questionnaire survey was conducted to collect information on the practice of CRT optimization of physicians who implant CRT devices in Japan. The collected data were focused on the method used to optimize AV and VV delays, the time required for the optimization, and the frequency of repetitive optimization during follow-up visits. The English translation of the questionnaire is shown in Table 1. Physicians who use device functions such as QuickOpt (St. Jude Medical, Minneapolis, MN, USA) , which monitor intracardiac electrograms, to optimize CRT parameters were instructed to mark “Other” and specify this on the answer sheets. The participating physicians were selected from centers that perform frequent CRT device implantations, nominally more than 10 procedures per year. Additional care was taken to minimize regional variance by selecting centers from each geographical area in Japan. Owing to the foreseen difficulty, centers in northeastern Japan were excluded because that region was severely affected by the March 11, 2011, earthquake. Descriptive statistics were performed for categorical variables. Statistical significance was not analyzed owing to the nature of this study.
Discussion This report describes the daily practices with regard to AV and VV delay optimization by physicians managing CRT patients in Japan. Most of the physicians responded that they only optimize AV and VV delays once at pre-hospital discharge and very few physicians regularly optimized AV and/or VV delay settings thereafter. A low rate of routine CRT device optimization has also been reported in physician surveys obtained from other countries . The effectiveness of repetitive optimization is currently unclear, and it is presently unknown whether the device parameters optimized at pre-hospital discharge would remain optimal in the long term. The lack of time and human resources were the major obstacles preventing frequent optimization. The fact that there have been no established, reliable standardized methods for optimizing CRT may be another factor influencing the frequency of optimization. The physicians\' perception toward optimization with unreliable methods may reflect upon their judgment about the necessity of optimizing CRT devices, thus further reducing the rate of repetitive optimization. The correlation between a standardized optimization method and CRT responsiveness is yet to be elucidated. Although echocardiographic evaluation can be time consuming and costly, this method is being used most frequently by Japanese physicians when performing device optimization, similar to previous reports from other countries . To reduce the increasing burden of CRT device follow-up and to allow timely optimization of these devices, optimization algorithms such as QuickOpt  and SmartDelay (Boston Scientific, Natick, MA, USA) [21,22] have been developed. These features monitor the heart conditions of patients to calculate the most optimal AV and/or VV delays and assist the physicians in reprogramming the devices during follow-ups. Although none of the physicians chose either of those device algorithms as their most frequently used method for optimizing AV and/or VV delays, 2 of them stated that they do incorporate device-suggested values as a reference. One limitation of these algorithms is that they are not automated and still require compliance with routine in-office reprogramming. Another newly developed algorithm, SonR (Sorin CRM SAS, Clamart, France) [23–25], performs weekly automated optimization of the AV delay, but the patients need to visit the clinic in order to have the VV delay optimized. The requirement for multiple clinic visits and for the manual optimization of the CRT configuration by methods such as echocardiography and device functionalities may be burdensome to both patients and physicians. A fully automated and self-reprogramming CRT optimization algorithm may reduce the burden of optimization by minimizing the need for routine office visits and may prove beneficial by allowing continuous adjustment of device settings according to the most recent clinical status of the patient. The efficacy of repetitive CRT optimization is yet to be elucidated, as intermittent reprogramming of the device during each follow-up visit may not reflect the continuous change of biological status in patients. However, landmark trials such as MIRACLE , COMPANION , and CARE-HF  required the AV and VV delays to be optimized at pre-hospital discharge and during each follow-up visits. A new algorithm that continuously monitors cardiac conduction and automatically reprograms AV and VV delays is being evaluated . With this new technology, it may be possible to constantly update the CRT parameters to reflect the most recent cardiac condition. As the effectiveness of AV and VV delay optimization is still under discussion, the next goal would be to clarify the correlation between the patient outcome and the optimal CRT in the long term.