Diagnosis and management of heart failure in the outpatient setting

Cerebral blood flow velocity and vasomotor reactivity during autonomic challenges in heart failure

BACKGROUND

Significant alterations in autonomic nervous system (ANS) function, vasomotor reactivity, and cerebral blood flow may develop from damage to brain ANS regulatory areas in heart failure (HF). This preferentially right-sided injury occurs largely in autonomic structures perfused by the middle cerebral artery. Indications of altered, asymmetrical perfusion raise the potential for further neural damage.

OBJECTIVE

To determine whether the extent of middle cerebral artery blood flow velocity and vasomotor reactivity is altered on one side of the brain over the other in HF versus control subjects, three ANS challenges were administered-each challenge recruited ANS regulatory areas potentially injured in HF.

METHODS

Transcranial Doppler ultrasonography was used to measure cerebral blood flow velocity and vasomotor reactivity in 40 HF (mean age = 52.7 years, SD = 7.5; 27 men; left ventricular ejection fraction = 26.8, SD = 8.3) and 42 control subjects (mean age = 48.3 years, SD = 6.0; 22 men) during 5% CO2 and hyperventilation, Valsalva, and orthostatic (upper body tilt) challenges.

RESULTS

Lower cerebral blood flow velocity and abnormal vasomotor reactivity (p < .01) were noted in HF middle cerebral arteries during all challenges. More right-sided flow velocity reductions appeared in HF, with laterality differences noted during CO2 and orthostatic (p < .05), but not Valsalva challenges.

DISCUSSION

Diminished cerebral blood flow velocity and altered vasomotor reactivity were associated with HF, changes being preferentially on the right side; the asymmetry was more pronounced during CO2 and orthostatic challenges. The impaired blood flow regulation may contribute to the lateralized brain pathology in ANS areas, undermining autonomic control in HF.

Acute effects of continuous positive air way pressure on pulse pressure in chronic heart failure

BACKGROUND

Patients with heart failure (HF) have left ventricular dysfunction and reduced mean arterial pressure (MAP). Increased adrenergic drive causes vasoconstriction and vessel resistance maintaining MAP, while increasing peripheral vascular resistance and conduit vessel stiffness. Increased pulse pressure (PP) reflects a complex interaction of the heart with the arterial and venous systems. Increased PP is an important risk marker in patients with chronic HF (CHF). Non-invasive ventilation (NIV) has been used for acute decompensated HF, to improve congestion and ventilation through both respiratory and hemodynamic effects. However, none of these studies have reported the effect of NIV on PP.

OBJECTIVE

The objective of this study was to determine the acute effects of NIV with CPAP on PP in outpatients with CHF.

METHODS

Following a double-blind, randomized, cross-over, and placebo-controlled protocol, twenty three patients with CHF (17 males; 60±11 years; BMI 29±5 kg/cm2, NYHA class II, III) underwent CPAP via nasal mask for 30 min in a recumbent position. Mask pressure was 6 cmH2O, whereas placebo was fixed at 0-1 cmH2O. PP and other non invasive hemodynamics variables were assessed before, during and after placebo and CPAP mode.

RESULTS

CPAP decreased resting heart rate (Pre: 72±9; vs. Post 5 min: 67±10 bpm; p<0.01) and MAP (CPAP: 87±11; vs. control 96±11 mmHg; p<0.05 post 5 min). CPAP decreased PP (CPAP: 47±20 pre to 38±19 mmHg post; vs. control: 42±12 mmHg, pre to 41±18 post p<0.05 post 5 min).

CONCLUSION

NIV with CPAP decreased pulse pressure in patients with stable CHF. Future clinical trials should investigate whether this effect is associated with improved clinical outcome.

Investigating the performance improvement of HRV Indices in CHF using feature selection methods based on backward elimination and statistical significance

In this study, the best combination of short-term heart rate variability (HRV) measures was investigated to distinguish 29 patients with congestive heart failure from 54 healthy subjects in the control group. In the analysis performed, wavelet packet transform based frequency-domain measures and several non-linear parameters were used in addition to standard HRV measures. The backward elimination and unpaired statistical analysis methods were used to select the best one among all possible combinations of these measures. Five distinct typical classifiers with different parameters were evaluated in discriminating these two groups using the leave-one-out cross validation method. Each algorithm was tested 30 times to determine the repeatability of the results. The results imply that the backward elimination method gives better performance when compared to the statistical significance method in the feature selection stage. The best performance (82.75%, 96.29%, and 91.56% for the sensitivity, specificity, and accuracy) was obtained by using the SVM classifier with 27 selected features including non-linear and wavelet-based measures.

Use of a device to support standing during a physical activity program to improve function of individuals with disabilities who reside in a nursing home

PURPOSE

To demonstrate the feasibility of an innovative program of physical activity using a standing-support device targeted towards adult residents of a nursing home who are unable to transfer or stand independently.

METHOD

Intervention study.

PARTICIPANTS

Thirteen residents, age 82 +/- 11 years, at the Beit Bayer Nursing Home, Jerusalem, Israel, who were unable to transfer or stand independently.

INTERVENTION

Eight-week observational period followed by 12-week physical activity performed while standing in a Standing-Support Device.

MEASUREMENTS

Manual Muscle Testing, joint range of motion, forward and lateral reach, time to stand independently, distance walked with a walker, Functional Independence Measure.

RESULTS

Compared to the observational period, significant post-intervention improvements were noted particularly in lower extremity muscle strength. Improvements in the Functional Independence Measure were noted in sphincter control, locomotion, mobility, motor score, and total score. Over 60% of those previously requiring assistance in standing became able to stand for an average of 1 min unassisted and walk an average of 14 m with a walker.

CONCLUSION

A pilot program of physical activity using a Standing-Support Device is feasible in selected stance-disabled older adult nursing home residents. Participants showed evidence of muscle strength and functional improvement. Future studies of the device with a concurrent examination of healthcare costs, functional improvement, and staff burden, are recommended.