Heterogenous haemodynamic effects of adaptive servoventilation therapy in sleeping patients with heart failure and Cheyne-Stokes respiration compared to healthy volunteers.

This study investigated the haemodynamic effects of adaptive servoventilation (ASV) in heart failure (HF) patients with Cheyne-Stokes respiration (CSR) versus healthy controls. Twenty-seven HF patients with CSR and 15 volunteers were ventilated for 1 h using a new ASV device (PaceWave™). Haemodynamics were continuously and non-invasively recorded at baseline, during ASV and after ventilation. Prior to the actual study, a small validation study was performed to validate non-invasive measurement of Stroke volume index (SVI). Non-invasive measurement of SVI showed a marginal overall difference of -0.03 ± 0.41 L/min/m(2) compared to the current gold standard (Thermodilution-based measurement). Stroke volume index (SVI) increased during ASV in HF patients (29.7 ± 5 to 30.4 ± 6 to 28.7 ± 5 mL/m(2), p < 0.05) and decreased slightly in volunteers (50.7 ± 12 to 48.6 ± 11 to 47.9 ± 12 mL/m(2)). Simultaneously, 1 h of ASV was associated with a trend towards an increase in parasympathetic nervous activity (PNA) in HF patients and a trend towards an increase in sympathetic nervous activity (SNA) in healthy volunteers. Blood pressure (BP) and total peripheral resistance response increased significantly in both groups, despite marked inter-individual variation. Effects were independent of vigilance. Predictors of increased SVI during ASV in HF patients included preserved right ventricular function, normal resting BP, non-ischaemic HF aetiology, mitral regurgitation and increased left ventricular filling pressures. This study confirms favourable haemodynamic effects of ASV in HF patients with CSR presenting with mitral regurgitation and/or increased left ventricular filling pressures, but also identified a number of new predictors. This might be mediated by a shift towards more parasympathetic nervous activity in those patients.

Respiratory effects of adaptive servoventilation therapy in patients with heart failure and Cheyne-Stokes respiration compared to healthy volunteers.

BACKGROUND: Nocturnal adaptive servoventilation (ASV) therapy is now frequently used to treat Cheyne-Stokes respiration (CSR), which is highly prevalent in patients with moderate-to-severe heart failure (HF) and characterized by periodical breathing (hyperventilation). OBJECTIVES: This study analyzed and compared the acute effects of a novel ASV device on carbon dioxide pressure (pCO2) and oxygen saturation (SaO2) in HF patients with CSR and healthy volunteers. The influence of being asleep or awake on the ASV algorithm was also determined. METHODS: All subjects underwent ASV (PaceWave™, ResMed) for 1 h. Transcutaneous pCO2 (PtcCO2) and SaO2 were assessed transcutaneously, while wakefulness was analyzed using EEG recordings. Assessments were made 30 min before and after ASV, and during 1 h of ASV. RESULTS: Twenty HF patients (19 male; age 79 ± 12 years) and 15 volunteers (13 male, age 25 ± 4 years) were included. When awake, ASV was associated with a trend towards a decrease in PtcCO2 and an increase in SaO2 versus baseline in HF patients (34.4 ± 3.2 to 33.7 ± 3.8 mm Hg and 93.8 ± 2.6 to 94.9 ± 2.6%, respectively) and volunteers (39.5 ± 3.0 to 38.2 ± 3.8 mm Hg and 96.9 ± 1.3 to 97.8 ± 0.9%). While asleep during ASV, PtcCO2 increased to 36.3 ± 3.8 mm Hg and SaO2 decreased to 93.8 ± 2.6% in HF patients, with similar changes in volunteers (PtcCO2 41.7 ± 3.0 mm Hg, SaO2 97.1 ± 1.2). All comparisons were statistically significant (p ≤ 0.05, except the PtcCO2 decrease in both groups when awake). CONCLUSIONS: ASV therapy might result in hyperventilation when subjects are awake, but while asleep, PtcCO2 increased to mid-normal values, effects that would be favorable in HF patients with CSR.

Validation of blood pressure monitoring using pulse transit time in heart failure patients with Cheyne-Stokes respiration undergoing adaptive servoventilation therapy.

PURPOSE: Using pulse transit time (PTT) and an ECG appears to be a promising alternative for invasive or noninvasive monitoring of blood pressure (BP). This study assessed the validity of PTT for BP monitoring in clinical practice. METHODS: Twenty-nine patients with chronic heart failure (HF; 27 male, 70.5 ± 9.9 years) and nocturnal Cheyne-Stokes respiration were noninvasively ventilated for one hour using adaptive servoventilation (ASV) therapy (PaceWave, ResMed). BP was measured using two devices (oscillometrically via Task Force Monitor, CNSystems and PTT via SOMNOscreen, Somnomedics) at least every 7 min for 30 min before, during, and after ASV. RESULTS: Mean systolic BP was 118.1 ± 14.4 mmHg vs. 115.9 ± 14.1 mmHg for oscillometric method vs PTT, respectively. Corresponding values for diastolic BP were 72.3 ± 10.3 mmHg and 69.4 ± 11.1 mmHg. While clinically comparable, differences between the two methods were statistically significant (p < 0.05). The difference between the two methods showed an increasing trend over time. A total of 18.5 % of PTT-based measurements could not be analyzed. The direction of a change in BP was opposite for PTT vs oscillometry for 17.0 % and 32.8 % of systolic and diastolic BP measurements, respectively. CONCLUSIONS: When monitoring BP in HF patients, overall BP monitoring using PTT is comparable to oscillometry for a period of 2 h (including a 1-h ASV phase). However, PTT shows a tendency to underestimate BP over time and during ASV.

Echocardiographic particle image velocimetry for the evaluation of diastolic function in hypertrophic nonobstructive cardiomyopathy.

AIMS: To use particle image velocimetry (PIV) echocardiography for the evaluation of diastolic dysfunction (DD) in patients with hypertrophic nonobstructive cardiomyopathy (HNCM). METHODS: This study included 50 individuals, thereof 30 patients with DD due to HNCM and 20 healthy individuals who served as controls. HNCM patients were divided into 3 groups according to DD severity. All subjects underwent clinical assessment, exercise testing, and standard as well as PIV echocardiography. RESULTS: Energy dissipation was higher in DD patients than in the control group. The severity of flow pattern disturbance corresponded to the degree of DD. In a subgroup of 20 HNCM patients we found significant correlations between invasive measured left ventricular end-diastolic pressure and noninvasive PIV parameters for intraventricular pressure differences and filling. Inter-observer variability (mean difference ± 1.96 SD) for all tested PIV measurements was good. CONCLUSION: According to DD severity, patients with HNCM have disturbed intraventricular flow and reduced intraventricular pressure differences, consistent with a reduced intraventricular suction. PIV echocardiography appears to be feasible for detailed analysis of ventricular vortex flow in DD conditions. Further research using PIV echocardiography in different cardiac pathologies seems warranted.

Rethinking cardiac resynchronization therapy: the impact of ventricular dyssynchrony on outcome.

OBJECTIVE: To analyze whether left ventricular dyssynchrony (LVD) at baseline is predictive for long-term outcome in heart failure (CHF) patients with left ventricular (LV) dysfunction and conduction disturbances treated with cardiac resynchronization therapy (CRT). METHODS: In 535 consecutive individuals with CHF scheduled for implantation of a CRT device, LVD was assessed by tissue Doppler imaging (TDI), defined as an electromechanical delay (EMD) difference of ≥40 ms in 2 opposed left ventricular wall regions (septal vs. lateral, anterior vs. inferior). All-cause mortality, heart transplantation, or assist device implantation was defined as combined primary end point. Secondary end points were measures of reverse LV remodeling and of symptomatic improvement. RESULTS: Mean follow-up was 68 ± 36 [range: 4-150] months. LVD at baseline was present in 308 patients (61%). Of these, 24% reached the combined primary endpoint in contrast to 58% of patients without LVD (p < 0.001). Furthermore, patients with LVD showed pronounced improvement of all secondary end point parameters. In our cohort LVD was an independent predictor for outcome (hazard ratio [95% CI]: 0.30 [0.21-0.42], p < 0.001). CONCLUSIONS: LVD at baseline as assessed by TDI is associated with a more pronounced clinical improvement and is a predictor for transplant-free long-term survival in CRT recipients.

Left ventricular dyssynchrony predicts clinical response to CRT - a long-term follow-up single-center prospective observational cohort study.

BACKGROUND: Until now, there is no consensus regarding the definition of a clinical response to cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF) and systolic left ventricular (LV) dysfunction. The aim of this study was to evaluate if echocardiography is predictive for an objective improvement in exercise capacity during long-term follow-up of CRT. METHODS: Each patient underwent echocardiography and spiroergometry both at baseline and at last follow-up. Left ventricular dyssynchrony (LVD) before CRT was defined by tissue Doppler imaging (TDI) as intra-LV delay ≥40 msec (septal-lateral or anterior-posterior). Clinical response to CRT was defined as increase of peakVO2 or as increase of maximal workload >10% as compared to baseline. RESULTS: Mean follow-up was 69 ± 37 months. From the 238 consecutive patients included in the study, 141 (59%) were classified as clinical responders and 97 (41%) as nonresponders. Baseline data of responders and nonresponders were comparable. However, clinical responders showed more often LVD (64%) than nonresponders (42%, P = 0.004). On multivariate regression analysis, nonischemic origin of CHF (ß-coefficient in the final model 0.1, P = 0.04) and LVD at baseline (ß-coefficient in the final model 0.2, P < 0.001) were independently associated with clinical response during long-term follow-up. Patients with LVD at baseline had significant more often an improvement of left ventricular ejection fraction >10% (P = 0.02) and a reduction of left ventricular end-diastolic diameter (LVEDD) >10% (P < 0.01) than patients without LVD at baseline. CONCLUSIONS: LVD at baseline as assessed by a straightforward echocardiographic approach predicts the long-term clinical response to CRT and is associated with a more pronounced reverse LV remodeling.

Myocardial fibrosis severity on cardiac magnetic resonance imaging predicts sustained arrhythmic events in hypertrophic cardiomyopathy.

BACKGROUND: The purpose of our study was to correlate the incidence of adequate implantable cardioverter-defibrillator (ICD) interventions in hypertrophic cardiomyopathy (HCM) patients with risk markers (RMs) for sudden cardiac death (SCD) plus myocardial fibrosis as detected by late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) imaging. METHODS: In all, 87 patients with HCM underwent LGE-CMR imaging prior to ICD implantation, performed for secondary (n = 2; 2%) or primary SCD prophylaxis (n = 85; 98%). Fibrosis was graded with a 17-segment left ventricular model (0 = absent, 1 = point-shaped, 2 = limited to 1 left ventricular segment, 3 = involving ≥ 2 segments). During follow-up, ICD memories were read out by a physician blinded to the individual patient data. RESULTS: The number of RMs per patient was 1.9 ± 0.8. Myocardial fibrosis was present in 78 patients (90%); 26 (30%) had a fibrosis score of 3. During follow-up (3.5 ± 2.6 [range, 0.2-11.4 years]), 15 patients had 50 appropriate ICD interventions. Episodes of atrial fibrillation were found in 28 patients. Fibrosis severity correlated with occurrence of ventricular tachycardia (Cramér's V, or φc = 0.4, P < 0.001) and atrial fibrillation (φc = 0.6, P < 0.001). On multivariate regression analysis, an independent association between myocardial fibrosis (ß = 0.6, P < 0.01) and sustained ventricular tachycardia was found. CONCLUSIONS: In HCM patients treated with ICD implantation because of a high SCD risk by traditional RM assessment, a high rate of arrhythmic events was observed during long-term follow-up. In a cohort of patients with clinical markers for high risk of SCD, severity of myocardial fibrosis as detected by an easy LGE-CMR scoring system was associated with future arrhythmic events and appropriate ICD therapies.

Complex sleep apnoea in congestive heart failure.

BACKGROUND: Sleep disordered breathing is common and of prognostic significance in patients with congestive heart failure (CHF). Complex sleep apnoea (complexSA) is defined as the emergence of central sleep apnoea during continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnoea (OSA). This study aims to determine the prevalence and predictors for complexSA in patients with CHF with OSA, and to assess the effects of treatment with adaptive servoventilation. METHODS: 192 patients with CHF (left ventricular ejection fraction (LVEF) ≤45%, New York Heart Association (NYHA) class ≥2) and OSA (apnoea-hypopnoea index (AHI) ≥15) were investigated using echocardiography, cardiopulmonary exercise testing, measurement of hyperoxic, hypercapnic ventilatory response, 6 min walk test and measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) prior to CPAP introduction. If patients demonstrated complexSA (AHI >15/h with <10% obstructive events) during CPAP titration, adaptive servoventilation was introduced and the investigations were repeated at 3 monthly follow-up visits. RESULTS: ComplexSA developed in 34 patients (18%) during CPAP titration. After adjustment for demographic and cardiac parameters, measures of CO(2) sensitivity (higher hyperoxic, hypercapnic ventilatory response) were independently associated with complexSA. Patients using adaptive servoventilation had improved AHI, NYHA class, NT-proBNP concentration, LVEF, hyperoxic, hypercapnic ventilatory response, oxygen uptake during cardiopulmonary exercise testing and the relationship between minute ventilation and the rate of CO(2) elimination (VE/Vco(2) slope) at last individual follow-up (14±4 months). CONCLUSION: There is a high prevalence of complexSA in patients with OSA and CHF, and those who develop complexSA have evidence of higher respiratory controller gain before application of CPAP. Treatment with adaptive servoventilation effectively suppressed complexSA and had positive effects on cardiac function and respiratory stability.

Adaptive servoventilation improves cardiac function and respiratory stability.

Cheyne-Stokes respiration (CSR) in patients with chronic heart failure (CHF) is of major prognostic impact and expresses respiratory instability. Other parameters are daytime pCO2, VE/VCO2-slope during exercise, exertional oscillatory ventilation (EOV), and increased sensitivity of central CO2 receptors. Adaptive servoventilation (ASV) was introduced to specifically treat CSR in CHF. Aim of this study was to investigate ASV effects on CSR, cardiac function, and respiratory stability. A total of 105 patients with CHF (NYHA ≥ II, left ventricular ejection fraction (EF) ≤ 40%) and CSR (apnoea-hypopnoea index ≥ 15/h) met inclusion criteria. According to adherence to ASV treatment (follow-up of 6.7 ± 3.2 months) this group was divided into controls (rejection of ASV treatment or usage <50% of nights possible and/or <4 h/night; n = 59) and ASV (n = 56) adhered patients. In the ASV group, ventilator therapy was able to effectively treat CSR. In contrast to controls, NYHA class, EF, oxygen uptake, 6-min walking distance, and NT-proBNP improved significantly. Moreover, exclusively in these patients pCO2, VE/VCO2-slope during exercise, EOV, and central CO2 receptor sensitivity improved. In CHF patients with CSR, ASV might be able to improve parameters of SDB, cardiac function, and respiratory stability.