Herweg et al evaluated the benefit of CRT in

Herweg et al. [9] evaluated the benefit of CRT in 10 consecutive patients with NYHA class IV HF who were dependent on inotropic support. Their patients had received inotropic support for 146±258 days, and all patients were alive at the mean follow-up of 1088±284 days after CRT. They also reported an improvement in LVEF (23.5±4.3% to 32.0±9.1%; p<0.05). Cowburn et al. [12] identified 10 patients who required inotropic support and underwent CRT while being administered with inotropic agents. All patients were weaned from inotropic agents and survived to hospital discharge. These reports are congruent with our report and support the beneficial effects of CRT for patients with inotrope-dependent HF. However, Adelstein et al. [13] reported conflicting findings. They divided their cohort of CRT patients into 3 groups according to exposure to intravenous inotropes before CRT—(1) no inotropes, (2) previous inotrope administration, and (3) dependent on inotropes—and compared the clinical outcomes. In their study, 16 inotrope-dependent patients were identified and the 1-year survival rate was <20%. In addition, inotrope-dependent patients exhibited neither functional improvement nor reverse remodeling in their study. The discrepancy between our study and their report may be partly explained by the fact that many of their patients had LVAD implantation and cardiac transplantation. It may be easier to assess LVAD or cardiac transplantation owing to the differences in social background. Moreover, most of our patients had non-ischemic cardiomyopathy, and were generally thought to benefit more from CRT than ischemic cardiomyopathy patients. Bhattacharya et al. [14] also reported negative effects of CRT for patients with HF on inotropes at implantation. They retrospectively analyzed >700 CRT-defibrillator recipients and categorized them as never on inotropes (NI group), weaned from inotropes before implantation, or on inotropes at implantation (II group). Their control group comprised patients with a standard defibrillator. They compared the overall survival and survival free from trp channels transplant or LVAD between those 4 groups. On the basis of their report, the II group patients demonstrated significantly shorter survival than the NI group patients at 12 months (hazard ratio, 2.95; 95% confidence interval, 1.05–8.35), and CRT may not have a survival advantage over a standard defibrillator for patients who had received inotropes before CRT. The propensity score-adjusted event-free survival rate in II group patients with regard to LVAD and heart transplantation at 12 months was around 60%, and the overall survival at 12 months was about 70%. Their survival rate was much better compared with that in the previously described reports; however, the authors reported no beneficial effects of CRT for inotrope-dependent HF patients. Their cohort was the largest study cohort of CRT patients on inotropic support; however, the II group was not exactly inotrope-dependent (i.e., they simply defined the II group as patients on inotropes at CRT implantation). Furthermore, the control group of patients with a standard defibrillator comprised only 3% of NYHA class IV patients, and these control group patients were thought to have milder HF than the II group patients. From this point of view, the effectiveness of CRT in inotrope-dependent HF patients could not be entirely denied.
Conclusions
Conflict of interest
Acknowledgments
Introduction The early prediction and diagnosis of heart failure (HF) are important when managing patients with chronic HF. In the Tele-HF study [1], the incidence of decompensated HF events over a 180-day period was compared between patient groups with and without home monitoring of HF symptoms and body weight with the use of a telephone circuit. The study noted no differences in the rates of readmission and all-cause mortality between the 2 groups, revealing the limitation of monitoring only HF symptoms and body weight. Recently, remote monitoring with the use of cardiovascular implantable electric devices has been developed, and the feasibility of the early diagnosis of HF has been investigated. Intrathoracic impedance was shown to be inversely correlated with the total body fluid volume and pulmonary wedge pressure [2]; thus, early diagnosis of HF by continuous impedance monitoring was feasible. The Medtronic remote monitoring system, CareLink Network, allows not only early detection of a malfunction of the implanted device and arrhythmic events, but also continuous intrathoracic impedance monitoring via OptiVol® Fluid Status monitoring alerts™.