Guidelines for the treatment of heart failure (HF) recommend the titration of β blockers (BB) to a target dosage shown to be effective in clinical trials. The benefit of BBs is associated with heart rate (HR) control, with a target resting HR <70 bpm which in clinical trials have been associated with improved clinical outcomes. The primary purpose of this study was to gauge the ability to achieve guideline-directed medical therapy HR control in the early posthospitalization period for HF patients with the wearable cardioverter defibrillator (WCD), assessing whether the WCD could be used to evaluate HR both at rest and during activity to determine if targets were being met and to adequately direct clinical decision making. The WCD platform allows continuous recording of HR. To assess the guideline-directed therapy goals for reduction of resting HR, HR was evaluated both at rest (nighttime: midnight-7 a.m.; daytime: 7 a.m. midnight), and during activity of daily living. HR data during activity of daily living (ADL) and rest were collected from patients with HF that wore the WCD for ≥5 weeks (n = 1,353) between 2015 and 2017. First, 643,891 activity episodes from 1,353 patients were analyzed. Daytime and nighttime resting HRs significantly dropped from beginning to end of WCD use (day: 72.5 bpm vs 69.0 bpm, p <0.0001; night: 68.1 vs 64.3, p <0.0001). However, 43% of patients still had an average daytime resting HR ≥70 bpm during the last week of WCD use. When comparing a patient’s peak activity HR during the first week of WCD use to the last week, there was no difference (93.6 bpm vs 94.1 bpm, p = 0.23). During ADL, 31% of patients had a HR ≥100 bpm, 14% of patients had a HR ≥110 bpm, and 6% had a HR ≥120 bpm. In conclusion, months after hospital discharge, 43% of patients did not meet guideline-directed resting target HR control, indicating they may not have been effectively managed with BB. HR during ADL may have also been higher than preferred. Remote HR monitoring may help physicians to adequately titrate guideline-directed medical therapy, thus improving clinical outcomes in HF patients.