Relationships between Heart Chamber Morphology or Function and Respiratory Parameters in Patients with HFrEF and Various Types of Sleep-Disordered Breathing.

Sleep-disordered breathing (SDB), i.e., central sleep apnea (CSA) and obstructive sleep apnea (OSA), affects the prognosis of patients with heart failure with reduced ejection fraction (HFrEF). The study assessed the relationships between heart chamber size or function and respiratory parameters in patients with HFrEF and various types of SDB. The 84 participants were patients aged 68.3 ± 8.4 years (80% men) with an average left ventricular ejection fraction (LVEF) of 25.5 ± 6.85% who qualified for cardioverter-defibrillator implantation with or without cardiac resynchronization therapy. SDB, defined by an apnea-hypopnea index (AHI) ≥ five events/hour, was diagnosed in 76 patients (90.5%); SDB was severe in 31 (36.9%), moderate in 26 (31.0%), and mild in 19 (22.6%). CSA was the most common type of SDB (64 patients, 76.2%). A direct proportional relationship existed only in the CSA group between LVEF or stroke volume (SV) and AHI (p = 0.02 and p = 0.07), and between LVEF or SV and the percentage of total sleep time spent with hemoglobin oxygen saturation < 90% (p = 0.06 and p = 0.07). In contrast, the OSA group was the only group in which right ventricle size showed a positive relationship with AHI (for basal linear dimension [RVD1] p = 0.06), mean duration of the respiratory event (for RVD1 p = 0.03, for proximal outflow diameter [RVOT proximal] p = 0.009), and maximum duration of respiratory event (for RVD1 p = 0.049, for RVOT proximal p = 0.006). We concluded that in HFrEF patients, SDB severity is related to LV systolic function and SV only in CSA, whereas RV size correlates primarily with apnea/hypopnea episode duration in OSA.

Severe sleep apnea as a predictor of failure to respond to cardiac resynchronization therapy.

BACKGROUND: The response to cardiac resynchronization therapy (CRT) is suboptimal in one-third of patients. OBJECTIVES: The study aimed to evaluate the impact of sleep-disordered breathing (SDB) on the CRT-induced left ventricular (LV) reverse remodeling and response for CRT in patients with ischemic congestive heart failure (CHF). METHODS: A total of 37 patients aged 65.43 years (SD 6.05), seven of whom were females, were treated with CRT according to class I European Society of Cardiology recommendations. Clinical evaluation, polysomnography, and contrast echocardiography were performed twice during the six-month follow-up (6M-FU) to assess the effect of CRT. RESULTS: In 33 patients (89.1%), sleep-disordered breathing (SDB), predominantly central sleep apnea (70.3%) was observed. This include nine patients (24.3%) with an apnea-hypopnea index (AHI) of >30 events/hour. During the 6M-FU, 16 patients (47.1%) responded to CRT by reducing LV end-systolic volume index (LVESVi) by ≥15%. We stated a directly proportional linear relationship between AHI value and LV volume: LVESVi p = 0.004, and LV end-diastolic volume index p = 0.006. CONCLUSIONS: Pre-existing severe SDB can impair the LV volumetric response to CRT even in an optimally selected group with class I indications for resynchronization, which may have an impact on long-term prognosis.

The usefulness of telemedicine devices in patients with severe heart failure with an implanted cardiac resynchronization therapy system during two years of observation.

BACKGROUND: Heart failure (HF) remains a disease with a poor prognosis. Telemonitoring is a medical service aimed at remote monitoring of patients. AIM: The study aimed to identify the clinical relevance of non-invasive telemonitoring devices in HF patients. METHODS: Sixty patients aged 66.1 (11) years, with left ventricular ejection fraction (LVEF) 26.3 (6.8)% underwent cardiac resynchronization therapy (CRT) implantation. They were randomly allocated to the control (standard medical care) or study (standard medical care + telemonitoring device) groups. During the follow-up (24 months), the patients in the study group provided body mass and blood pressure, along with electrocardiogram on a daily basis. The data were transferred to themonitoring center and consulted with a cardiologist. Transthoracic echocardiography and a 6-minute walk test were performed before and 24 months after CRT implantation. RESULTS: During the two-year observation, the composite endpoint (death or HF hospitalization) occurred in 21 patients, more often in the control group (46.8% vs. 21.4%; P = 0.026). Inunivariate analysis: the use of telemetry (hazard ratio [HR], 0.2; 95% confidence interval [CI], 0.07-0.7; P=0.004), thepresence of coronary heart disease (HR, 41.4; 95% CI, 3.1-567.7; P=0.005), hypertension (HR, 0.24; 95% CI, 0.07-0.90; P = 0.035), and patient's body mass (HR, 0.36; 95% CI, 0.14-0.92; P = 0.03) were related to the occurrence of the composite endpoint. CONCLUSIONS: The use of a telemonitoring device in CRT recipients improved theprognosis in2-year observation and contributed to the reduction of HF hospitalization.

The beneficial impact of cardiac rehabilitation on obstructive sleep apnea in patients with coronary artery disease.

STUDY OBJECTIVES: To assess the impact of cardiac rehabilitation for decreasing sleep-disordered breathing in patients with coronary artery disease. METHODS: The study included 121 patients aged 60.01 ± 10.08 years, 101 of whom were men, with an increased pretest probability of OSA. The cardiac rehabilitation program lasted 21-25 days. The improvement in cardiorespiratory fitness was assessed using the changes in peak metabolic equivalents, the maximal heart rate achieved, the proportion of the age- and sex-predicted maximal heart rate, and the Six-Minute Walk Test distance. Level 3 portable sleep tests with respiratory event index assessments were performed in 113 patients on admission and discharge. RESULTS: Increases were achieved in metabolic equivalents (Δ1.20; 95% confidence interval [CI], 0.95-1.40; P < .0001), maximal heart rate (-Δ7.5 beats per minute; 95% CI, 5.00-10.50; P < .0001), proportion of age- and sex-predicted maximal heart rate (Δ5.50%; 95% CI, 4.00-7.50; P < .0001), and the Six-Minute Walk Test distance (Δ91.00 m; 95% CI, 62.50-120.00; P < .0001). Sleep-disordered breathing was diagnosed in 94 (83.19%) patients: moderate in 28 (24.8%) patients and severe in 27 (23.9%) patients, with a respiratory event index of 19.75 (interquartile range, 17.20-24.00) and 47.50 (interquartile range, 35.96-56.78), respectively. OSA was dominant in 90.40% of patients. The respiratory event index reduction achieved in the sleep-disordered breathing group was -Δ3.65 (95% CI, -6.30 to -1.25; P = .003) and was in parallel to the improvement in cardiorespiratory fitness in the subgroups with the highest effort load and with severe sleep-disordered breathing: -Δ6.40 (95% CI, -11.40 to -1.90; P = .03) and -Δ11.00 (95% CI, -18.65 to -4.40; P = .003), respectively. CONCLUSIONS: High-intensity exercise training during cardiac rehabilitation resulted in a significant decrease in OSA, when severe, in parallel with an improvement in cardiorespiratory fitness in patients with coronary artery disease.

[How to avoid cardiovascular consequences of the obstructive sleep apnea syndrome?]

Obstructive sleep apnea syndrome (OSAS) is caused by periodical upper airway occlusion during sleep resulting in snoring, episodes of apnea and excessive daytime sleepiness. OSAS is a risk factor for hypertension, arrhythmias, conduction disorders as well as stroke, coronary artery disease, chronic heart failure and pulmonary hypertension. Early polygraphy and polysomnography and continuous positive airway pressure (CPAP) treatment reduce risks of cardiovascular diseases (CVD) in patients with OSAS.