CRT-D or CRT-P in CRT-indicated patients?

HRV parameters and 6-minute walking test, functional capacity, right ventricular systolic function, BNP and hs-troponin-I levels. Most common cause of death in these patients is arrhythmia, and autonomic dysfunction may be triggering factor (2). HRV parameters are now being used for prognostic evaluation in PAH patients. There are also studies suggesting HRV reduction may be associated with mortality and need for transplant in children and poor prognosis in adults with idiopathic PAH (3). Considering the fact that our patients were clinically stable and were also under appropriate treatment, guideline-recommended prognostic markers were not severely affected, despite significantly reduced HRV parameters. As a result, HRV parameters may be an early marker of prognosis even before deterioration of currently suggested markers. These data suggest that HRV parameters can be utilized as an early marker of poor prognosis in ES patients, but additional prospective studies are needed. The limited number of patients and lack of long-term follow up are the major limitations of this study. Frequency-domain parameters would also provide additional benefit.