Sleep Apnea Syndromes: Vardas PE

Vardas PE, Auricchio A, Blanc JJ, Daubert JC, Drexler H, Ector H, Gasparini M, Linde C, Morgado FB, Oto A, Sutton R, Trusz-Gluza M, Anonymous00373, Anonymous00374. · Department of Cardiology, Heraklion University Hospital, PO Box 1352 Stavrakia, GR-711 10 Heraklion (Crete), Greece. · Eur Heart J. · Pubmed #17726042 links to  free full text

This publication has no abstract.

Simantirakis EN, Schiza SE, Siafakas NS, Vardas PE. · Cardiology Department, Heraklion University Hospital, PO Box 1352, Heraklion, Crete, Greece. · Europace. · Pubmed #18682409 No free full text.

Abstract: Respiratory disturbances during sleep are common in patients with heart failure (HF) and can trigger the occurrence of sleep apnoea or deteriorate pre-existing breathing disorder. This in turn may lead to worsening of the HF itself. Optimal treatment for HF has been found to reduce respiratory disturbances during sleep significantly, whereas cardiac resynchronization therapy (CRT), achieved by biventricular pacing, appears to cause a further reduction in episodes of central type apnoea, although it may also have an effect on episodes of obstructive type. The beneficial effect of CRT is due to the patients' haemodynamic improvement and in the HF amelioration, and not due to some other effect resulting from the electrical stimulation of the heart. However, this therapeutic intervention by itself is insufficient for the effective treatment of respiratory disturbances during sleep and should be considered as an adjunctive treatment in addition to other established therapies.

Simantirakis EN, Vardas PE. · Cardiology Department, Heraklion University Hospital, PO Box 1352, Stavrakia, Heraklion, Crete, Greece. · Europace. · Pubmed #17043072 links to  free full text

Abstract: The sleep apnoea syndrome is a particularly common health problem associated with increased cardiovascular morbidity and mortality, as well as harmful socioeconomical and familial complications. In this article, the diagnostic and therapeutic role of cardiac pacing in this syndrome is discussed.

Vardas PE, Auricchio A, Blanc JJ, Daubert JC, Drexler H, Ector H, Gasparini M, Linde C, Morgado FB, Oto A, Sutton R, Trusz-Gluza M, Anonymous00304, Anonymous00305. · Department of Cardiology, Heraklion University Hospital, Heraklion, Crete, Greece. · Europace. · Pubmed #17726043 links to  free full text

This publication has no abstract.

Chrysostomakis SI, Simantirakis EN, Schiza SE, Karalis IK, Klapsinos NC, Siafakas NM, Vardas PE. · Department of Cardiology, University Hospital of Heraklion, Crete, Greece. · Hellenic J Cardiol. · Pubmed #16532711 links to  free full text

Abstract: INTRODUCTION: Sleep apnoea, which constitutes a major social problem because of its high prevalence and its emerging association with cardiovascular morbidity and mortality, is known to affect autonomic nervous system activity. We assessed the hypothesis that treatment of sleep apnoea patients with continuous positive airway pressure (CPAP) alters the indices of heart rate variability (HRV) that reflect sympathetic and parasympathetic autonomic nervous system activity. METHODS: We studied 26 patients (18 men, aged 49.2 +/- 7.6 years) with obstructive sleep apnoea-hypopnoea syndrome. In all patients, a 24-hour Holter recording was obtained one week before initiation of CPAP treatment and another one two months later. From these recordings we assessed the time domain indices of HRV (pNN50, rMSSD, SDNN, SDANN, SD) during the day (08:00-23:00) and during the night hours (23:00-08:00) as well as their post-treatment changes. The same HRV indices were also assessed in a group of 19 age and sex matched controls, without sleep apnoea. RESULTS: No significant differences in the HRV indices were observed during the daytime hours, while during the night both pNN50 and rMSSD were significantly higher in patients compared to controls (19.5 +/- 12.5 vs. 13.8 +/- 9.7, p=0.001, for pNN50 and 54.7 +/- 23.1 vs. 44.0 +/- 15.9, p=0.001, for rMSSD, for patients and controls respectively). No such differences were observed in any of the monitored indices following CPAP treatment. CONCLUSIONS: The indices that reflect parasympathetic activity are increased during the night in patients with obstructive sleep apnoea syndrome. CPAP treatment reduces the night time vagal indices of HRV to resemble those of normal controls. The reduction of parasympathetic activity may be one of the mechanisms responsible for the alleviation of bradyarrhythmic episodes following the initiation of CPAP therapy.

Simantirakis EN, Schiza SE, Chrysostomakis SI, Chlouverakis GI, Klapsinos NC, Siafakas NM, Vardas PE. · Department of Cardiology, Heraklion University Hospital, Heraklion, Crete, Greece. · N Engl J Med. · Pubmed #16354893 links to  free full text

Abstract: BACKGROUND: The role of atrial overdrive pacing (AOP) in sleep apnea remains uncertain. We prospectively evaluated the effect of AOP after 24 hours and after one month in patients with the obstructive sleep apnea-hypopnea syndrome and compared it with the use of nasal continuous positive airway pressure (n-CPAP). METHODS: We studied 16 patients with a moderate or severe case of the obstructive sleep apnea-hypopnea syndrome (baseline mean apnea-hypopnea index, 49) and normal left ventricular systolic function in whom a dual-chamber pacemaker had been implanted. After 48 hours, the patients were randomly assigned to AOP (pacing at 15 bpm above the spontaneous mean nocturnal heart rate) or backup atrial pacing (pacing at a heart rate below 40 bpm); the latter group began n-CPAP therapy one day later. After one month, the two groups switched therapies and were followed for an additional month. Polysomnographic studies were performed at baseline, on the first night after randomization, at crossover, and at the end of the study. RESULTS: During AOP, no significant changes were observed in any of the respiratory variables measured. The change in the apnea-hypopnea index at one month with AOP was +0.2 (95 percent confidence interval, -2.7 to +2.3; P=0.87). In contrast, all variables improved significantly after one month of n-CPAP (change in the apnea-hypopnea index, -46.3; 95 percent confidence interval, -56.2 to -36.5; P<0.001). CONCLUSIONS: Nasal continuous positive airway pressure therapy is highly effective for the treatment of the obstructive sleep apnea-hypopnea syndrome, whereas AOP has no significant effect.

Simantirakis EN, Schiza SI, Marketou ME, Chrysostomakis SI, Chlouverakis GI, Klapsinos NC, Siafakas NS, Vardas PE. · Department of Cardiology, Heraklion University Hospital, Box 1352, Stavrakia (Crete), 711 10 Heraklion, Crete, Greece. · Eur Heart J. · Pubmed #15191779 links to  free full text

Abstract: AIM: In this new era of insertable loop recorders, we studied obstructive sleep apnoea-hypopnoea syndrome (OSAHS) patients in order to evaluate their arrhythmias and the beneficial effect of Continuous Positive Airway Pressure treatment (CPAP), over a long-term period. METHODS AND RESULTS: We enrolled 23 patients (16 men, 50 +/- 11 years) with moderate and severe OSAHS. In all patients, an insertable loop recorder capable of monitoring the heart rhythm for 16 months was implanted. Cardiac pauses >3 s and bradycardic episodes <40 bpm during a 2-month period before, and for 14 months after, the CPAP application, were noted. In each period, the patients underwent two 24-h Holter recordings. Before treatment, 11 patients (47%) revealed severe cardiac rhythm disturbances, mostly nocturnal. Holter recordings showed disturbances in only 3 (13%) patients (P=0.039), those in whom the insertable loop device had recorded frequent episodes. Eight weeks after the initiation of treatment, the total number of the recorded episodes tended to decrease while, during the last 6 months of the follow-up, no episodes were recorded. CONCLUSION: Approximately half of OSAHS patients evidence severe cardiac rhythm disturbances, which are significantly reduced by CPAP. Holter recordings seem unable to precisely describe the incidence of severe brady-arrhythmias and the effect of treatment.