Rapid titration of carvedilol in patients with congestive heart failure: a randomized trial of automated telemedicine versus frequent outpatient clinic visits.

BACKGROUND: Because of potential side effects and logistical difficulty of titrating medications, outpatients with congestive heart failure rarely receive appropriate doses of carvedilol or other beta-blockers. To address these obstacles, we studied if an automated telemedicine system named TeleWatch (TW) could facilitate carvedilol titration in outpatients with left ventricular systolic dysfunction. METHODS: Forty-nine patients with New York Heart Association class II and III left ventricular systolic dysfunction, who were tolerating appropriate afterload-reducing therapy and not receiving beta-blockers, were enrolled into a 3-month study. Patients were randomized to have clinic-only (CO) (n = 24) carvedilol titration or titrations which combined clinic visits with TW monitoring (n = 25). All patients were seen in clinic biweekly, and those in the TW group were remotely monitored daily. Using a predefined algorithm, patients in the CO and TW groups were eligible for carvedilol titration on a biweekly or weekly basis, respectively, by physicians blinded to group assignment. RESULTS: There was no statistical difference in the mean final daily dose of carvedilol between the CO and TW groups (39.4 vs 36.2 mg/d, P = .52). Because remote telemedicine titrations were as successful as titrations in the clinic, the time to reach the final dose of carvedilol was significantly shorter in the TW group (33.6 vs 63.7 days, P < .0001). There were 5 serious adverse events in the study, 4 of which were in the TW group (P = .29); however, TW prospectively detected 2 adverse events. CONCLUSIONS: Remote monitoring with an automated telemedicine system can successfully facilitate titration of carvedilol in outpatients with New York Heart Association class II and III congestive heart failure.

Hypoxia, not the frequency of sleep apnea, induces acute hemodynamic stress in patients with chronic heart failure.

OBJECTIVES: This study was conducted to evaluate whether brain (B-type) natriuretic peptide (BNP) changes during sleep are associated with the frequency and severity of apneic/hypopneic episodes, intermittent arousals, and hypoxia. BACKGROUND: Sleep apnea is strongly associated with heart failure (HF) and could conceivably worsen HF through increased sympathetic activity, hemodynamic stress, hypoxemia, and oxidative stress. If apneic activity does cause acute stress in HF, it should increase BNP. METHODS: Sixty-four HF patients with New York Heart Association functional class II and III HF and ejection fraction <40% underwent a baseline sleep study. Five patients with no sleep apnea and 12 with severe sleep apnea underwent repeat sleep studies, during which blood was collected every 20 min for the measurement of BNP. Patients with severe sleep apnea also underwent a third sleep study with frequent BNP measurements while they were administered oxygen. This provided 643 observations with which to relate apnea to BNP. The association of log BNP with each of 6 markers of apnea severity was evaluated with repeated measures regression models. RESULTS: There was no relationship between BNP and the number of apneic/hypopneic episodes or the number of arousals. However, the burden of hypoxemia (the time spent with oxygen saturation <90%) significantly predicted BNP concentrations; each 10% increase in duration of hypoxemia increased BNP by 9.6% (95% confidence interval: 1.5% to 17.7%, p = 0.02). CONCLUSIONS: Hypoxemia appears to be an important factor that underlies the impact of sleep abnormalities on hemodynamic stress in patients with HF. Prevention of hypoxia might be especially important for these patients.