Maria T La Rovere

Publications (2)7.18 Total impact

• Article: A hybrid approach for continuous detection of sleep-wakefulness fluctuations: validation in patients with Cheyne-Stokes respiration.

  Gian D Pinna, Elena Robbi, Maria T La Rovere, Roberto Maestri
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  ABSTRACT: Fluctuations in sleep/wake state have been proposed as an important mechanism contributing to the development of oscillatory breathing patterns, including Cheyne-Stokes respiration in patients with heart failure. In order to properly assess the interactions between changes in state and changes in ventilatory parameters, a methodology capable of continuously and reliably detecting state transitions is needed. Traditional fixed-epoch analysis of polysomnographic recordings is not suitable for this purpose. Moreover, visual identification of changes in the dominant electroencephalogram activity at the transition from wakefulness to sleep and vice versa is often very subjective. We have therefore developed a hybrid approach--including both visual scoring and computer-based procedures--for continuous analysis of state transitions from polysomnographic recordings, specifically tailored for fluctuations between wakefulness and non-rapid eye movement-1 and -2 sleep. The overall analysis process comprises three major phases: (1) manual identification of relevant electroencephalogram/electrooculogram features and events, including a sample of unequivocal alpha and theta-delta activity; (2) automatic statistical discrimination of dominant electroencephalogram activity; and (3) state classification (wakefulness, non-rapid eye movement-1 and -2). The latter is carried out by merging information from visual scoring with the output of the discriminator. Validation has been carried out in 16 patients with heart failure during daytime Cheyne-Stokes respiration, using a training and testing set of electroencephalogram polysomnograms. The statistical discriminator correctly classified 99.1 ± 1.4% and 99.2 ± 1.1% of unequivocal alpha and theta-delta activity. This approach has therefore the potential to be used to reliably measure the incidence and location of sleep-wake transitions during abnormal breathing patterns, as well as their temporal relationship with major ventilatory events.
  Journal of Sleep Research 06/2012; 21(3):342-51. · 3.16 Impact Factor
• Article: Comparison of the prognostic values of invasive and noninvasive assessments of baroreflex sensitivity in heart failure.

  Maria T La Rovere, Roberto Maestri, Elena Robbi, Angelo Caporotondi, Gianpaolo Guazzotti, Oreste Febo, Gian D Pinna
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  ABSTRACT: No studies have compared the prognostic values of invasive (phenylephrine, Phe) and noninvasive (transfer function) assessments of baroreflex sensitivity (BRS). Three hundred and one heart failure patients [age: 53 ± 8 years, New York Heart Association class II-III: 88%, left-ventricular ejection fraction (LVEF): 28 ± 8%] underwent an 8 min ECG and arterial pressure recording, followed by Phe administration. Phe-BRS and transfer function BRS (TF-BRS) could be measured in 89 and 72% of cases, respectively. The correlation and the 5-95th percentiles of the difference between the two methods were 0.61 (P < 0.0001), and -7.6, +7.5 ms/mmHg, respectively. During a median of 36 months, 23% of the patients experienced a cardiac event. In the common dataset of 202 patients, both BRS measurements (<3 ms/mmHg) were significantly associated with the outcome (both P < 0.001), but Phe-BRS had a better discriminatory power (area under the curve (AUC): 0.74 vs. 0.66, P  = 0.03). Patients with a missing BRS (due to high grade ectopic activity) had a higher event rate (Phe-BRS: 38 vs. 24%, P  = 0.23; TF-BRS: 37 vs. 19%, P  = 0.002). Using this information, a prognostic index was derived for each BRS method, increasing measurability to 94 and 98%, respectively. Both indexes significantly predicted the outcome after adjustment for clinical covariates [hazard ratio (95% CI): 1.9 (1.1-3.3), P  = 0.03 for Phe index and 2.0 (1.1-3.7), P  = 0.02 for transfer function index]. Although the measurability of TF-BRS in heart failure patients is impaired, prognostic information can be extended to almost all patients, with a predictive power similar to that of Phe-BRS. The two measurements, however, convey a certain amount of independent prognostic information. Hence, TF-BRS can be integrated with but not replace Phe-BRS.
  Journal of hypertension 06/2011; 29(8):1546-52. · 4.02 Impact Factor