title: Influence of cardiac-resynchronization therapy on heart rate and blood pressure variability: 1-year follow-up.
abstract: BACKGROUND
  Several studies have shown that cardiac-resynchronization therapy (CRT) improves haemodynamic function, cardiac symptoms, and heart rate variability (HRV) and reduces the risk of mortality and sudden death in subjects with chronic heart failure (CHF). In subjects with CHF, power spectral values for the low-frequency (LF) component of RR variability < or =13 ms2, are associated with an increased risk of sudden death.
  
  
  OBJECTIVE
  To assess whether spectral indexes obtained by power spectral analysis of HRV and systolic blood pressure (SBP) variability could predict malignant ventricular arrhythmias in patients with severe CHF treated with an implantable cardioverter-defibrillator (ICD) alone or with ICD+CRT. In addition, changes in non-invasive spectral indices using short-term power spectral analysis of HRV and SBP variability during controlled breathing in 15 patients with CHF treated with an ICD alone and 16 patients receiving ICD+CRT, were assessed pre-treatment and at 1 year.
  
  
  RESULTS
  Arrhythmias necessitating an appropriate ICD shock were more frequent in subjects who had low LF power. CRT improved all spectral components, including LF power.
  
  
  CONCLUSIONS
  Low LF power values predict an increased risk of malignant ventricular arrhythmias; after 1 year of CRT most non-spectral and spectral data, including LF power, improved. Whether these improvements lead to better long-term survival in patients with CHF remains unclear.
authors.affiliation: Dipartimento di Scienze dell'Invecchiamento, I Clinica Medica, Policlinico Umberto I, Università La Sapienza, 00161 Rome, Italy. gianfranco.piccirillo@uniroma1.it
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Piccirillo
authors.forename: Damiano
authors.initials: D
authors.lastname: Magrì
authors.forename: Silvia
authors.initials: S
authors.lastname: di Carlo
authors.forename: Tiziana
authors.initials: T
authors.lastname: De Laurentis
authors.forename: Alessia
authors.initials: A
authors.lastname: Torrini
authors.forename: Sabrina
authors.initials: S
authors.lastname: Matera
authors.forename: Marzia
authors.initials: M
authors.lastname: Magnanti
authors.forename: Leda
authors.initials: L
authors.lastname: Bernardi
authors.forename: Franco
authors.initials: F
authors.lastname: Barillà
authors.forename: Raffaele
authors.initials: R
authors.lastname: Quaglione
authors.forename: Evaristo
authors.initials: E
authors.lastname: Ettorre
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Marigliano
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000517:prevention & control*