ECG Holter analysis to detect induced deconditioning on cardiac activity in bedridden volunteers

Introduction

Prolonged bed rest (BR) is an unnatural state, often related to hospitalization, chronic diseases and ageing, inducing reduced functional capacity in multiple body systems, possibly leading to cardiovascular deconditioning. We hypothesized that measuring this decline over time could represent the first step for the formulation of appropriate countermeasures or rehabilitation programs while in the hospital. Accordingly, our aim was to assess the effects of 10-day horizontal BR on cardiac electrical activity.

Methods

Ten healthy male volunteers (23±5 years) were enrolled in an hospital, after ethical approval and signed consent, to participate to a 10-day strict horizontal BR campaign, preceded and followed by 2 days in the facility, respectively as acclimatization and recovery. The 12-leads 24-hours Holter ECG (1000 Hz, H12+, Mortara Instrument Inc.) was acquired 1 day before BR (PRE), the 5th (BR5) and 10th day (BR10) of bedridden immobilization. From each recording, beat-to-beat RR and QTend interval series, as well as T wave amplitude (Tamp) and upslope (Tslope) were computed. Statistical analysis was applied to test changes induced by BR (ANOVA with Tukey test, p<0.05), separately for day (7:00–23:00) and night (23:00–7:00) periods.

Results

Daily RR and QTend duration increased during BR, with peak changes at BR5 compared to PRE (+13.3% and +3% respectively), and were still prolonged at BR10 (+12.6% and +2.6%). During the night, while RR increased (BR5:+5.3%; BR10:+1.3%), QTend was found progressively shortened (BR5: −1.6%; BR10: −2.9%). Also, day and night Tamp (BR10: −19.5%) and Tslope (BR10 day: −17.1%; night: −7.8%) were found progressively reduced with the duration of BR.

Conclusion

During BR, cardiac electrical activity is affected by 10-days bedridden immobilization. Noticeably, a mismatch in RR-QTend relation was visible at night, where vagal autonomic system activity is prevailing.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Agenzia Spaziale Italiana (ASI)

Analysis of changes in cardiac circadian rhythms of RR and QT induced by a 60-day head-down bed rest with and without nutritional countermeasure

PURPOSE

Prolonged weightlessness exposure generates cardiovascular deconditioning, with potential implications on ECG circadian rhythms. Head-down (- 6°) tilt (HDT) bed rest is a ground-based analogue model for simulating the effects of reduced motor activity and fluids redistribution occurring during spaceflight. Our aim was to evaluate the impact of 60-day HDT on the circadianity of RR and ventricular repolarization (QTend) intervals extracted from 24-h Holter ECG recordings, scheduled 9 days before HDT (BDC-9), the 5th (HDT5), 21st (HDT21) and 58th (HDT58) day of HDT, the 1st (R + 0) and 8th (R + 7) day after HDT. Also, the effectiveness of a nutritional countermeasure (CM) in mitigating the HDT-related changes was tested.

METHODS

RR and QTend circadian rhythms were evaluated by Cosinor analysis, resulting in maximum and minimum values, MESOR (a rhythm-adjusted mean), oscillation amplitude (OA, half variation within a night-day cycle), and acrophase (φ, the time at which the fitting sinusoid's amplitude is maximal) values.

RESULTS

RR and QTend MESOR increased at HDT5, and the OA was reduced along the HDT period, mainly due to the increase of the minima. At R + 0, QTend OA increased, particularly in the control group. The φ slightly anticipated during HDT and was delayed at R + 0.

CONCLUSION

60-Day HDT affects the characteristics of cardiac circadian rhythm by altering the physiological daily cycle of RR and QTend intervals. Scheduled day-night cycle and feeding time were maintained during the experiment, thus inferring the role of changes in the gravitational stimulus to determine these variations. The applied nutritional countermeasure did not show effectiveness in preventing such changes.

Secondary school teachers and mental health competence: Italy-United Kingdom comparison

AIM

The aim of this study was to evaluate the differences between teachers' knowledge about early psychosis among three different Italian cities and a UK sample.

METHODS

The sample consisted of 556 secondary school teachers from three different cities in Italy (Milan, Rome and Lamezia Terme) and London (UK). The research was based on the Knowledge and Experience of Social Emotional Difficulties Among Young People Questionnaire. The Italian version of the questionnaire was used in Italy.

RESULTS

Overall, 67.6% of English teachers, 58.5% of Milan's teachers, 41.8% of Rome's teachers and 33.3% of Lamezia Terme's teachers were able to recognize psychotic symptoms from a case vignette. Logistic regression analysis showed that 'city' was the only independent variable significantly related to the correct/wrong answer about diagnosis.

CONCLUSIONS

We found statistically significant differences between the three Italian samples and the UK sample regarding teachers' knowledge about first signs of psychosis. English teachers showed a better knowledge than Italian teachers in general. Teachers from Milan, where a specific early detection program was established in 2000, seemed to be more familiar with early signs of psychosis than teachers in the other two Italian towns.