Long-term monitoring of respiratory rate in patients with heart failure: the Multiparametric Heart Failure Evaluation in Implantable Cardioverter-Defibrillator Patients (MULTITUDE-HF) study.
BACKGROUND
Monitoring respiratory rate (RR) is recommended at the time of hospital presentation for acute decompensation in heart failure (HF). Device-based continuous monitoring of RR may be helpful for diagnostic and prognostic stratification after implantable cardioverter-defibrillator (ICD) implantation. This study was undertaken to analyze short- and long-term changes in ICD-measured RR and to relate RR with the patient's clinical status and the occurrence of HF events.


METHODS
One hundred twenty-four consecutive HF patients who received ICD endowed with this diagnostic capability (Boston Scientific Inc., Natick, MA, USA) were prospectively enrolled. Patients were followed up for 12 months.


RESULTS
At the baseline, the proportion of New York Heart Association (NYHA) class III-IV was higher among patients with daily maximum RR >27 breaths/min (third tertile) than those with <24 breaths/min (first tertile) (43 vs. 23%, p < 0.05). Moreover, the ejection fraction was lower (27 ± 7 vs. 34 ± 8%, p < 0.05). In patients with HF hospitalizations (33 events) and urgent visits for HF (15 events), the weekly average of RR calculated over the 7 days preceding hospital accesses did not differ from values recorded at the baseline and before scheduled follow-up visits. However, the weekly variation in RR (i.e., the difference between maximum and minimum values collected over the week) was significantly higher prior to hospitalization (p < 0.05). A weekly variation >3 breaths/min in maximum RR predicted an impending hospital admission for HF with sensitivity of 73 % and specificity of 57%.


CONCLUSIONS
In this study, elevated values of ICD-monitored RR identified patients with worse functional status and lower systolic function. The weekly variation in RR increased before HF exacerbation. This monitoring technology may represent a useful tool in the clinical management of patients with HF.
Cardiology, University of Tor Vergata, Viale Oxford, 81., 00133, Rome, Italy, forleo@me.com.
Giovanni B
GB
Forleo
Luca
L
Santini
Massimiliano
M
Campoli
Mario
M
Malavasi
Alberto
A
Scaccia
Maurizio
M
Menichelli
Umberto
U
Riva
Filippo
F
Lamberti
Giovanni
G
Carreras
Serafino
S
Orazi
Valentina
V
Ribatti
Luigi
L
Di Biase
Mariolina
M
Lovecchio
Andrea
A
Natale
Sergio
S
Valsecchi
Francesco
F
Romeo
D000368:Aged; D017147:Defibrillators, Implantable; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011446:Prospective Studies; D056152:Respiratory Rate / Q000502:physiology*; D012680:Sensitivity and Specificity