Biomedical subjects

Matthew N Bartels

Publications and source records attributed to Matthew N Bartels.

15 recordsLinked to original sources

PubMed2006

Effect of object transport on grasp coordination in multiple system atrophy.

We examined the effects of the parkinsonian variant of multiple-system atrophy (MSA-P) on grasp and forward transport and release of an object. Twelve patients with MSA-P and 10 age-matched control subjects performed the task with each of three object weights (200, 400, 800 gm). Subjects moved at a self-selected pace using a precision grip. The grip (normal) and load (tangential) forces and the object position were recorded. Results indicate subjects with MSA-P have temporal and force coordination deficits. Temporal delays were seen in all subjects with MSA-P, leading to prolonged overall movement times compared to control subjects. These delays occurred throughout the task, with significantly longer transport phases and delays releasing the object. Despite demonstrating an appropriate anticipatory scaling of forces, with increasing grip and load forces for heavier weights, force coordination was compromised in subjects with MSA-P. These subjects generated significant negative load forces prior to transporting the object. In addition, during the transport phase, subjects with MSA-P generated highly variable grip forces. Overall, the results indicate that subjects with MSA-P demonstrate bradykinesia and difficulty coordinating components of an object transport task.

Aged↗

PubMed2006

Cardiopulmonary rehabilitation and cancer rehabilitation. 1. Cardiac rehabilitation review.

UNLABELLED: Cardiac rehabilitation includes not only the rehabilitation of people with ischemic heart disease but also those with congestive heart failure, heart transplantation, congenital heart disease, and other conditions. New advances in medical treatment have arisen, and there are new approaches in treatment, including alternative medicine and complementary care. New surgical approaches that help restore cardiac function have also been introduced, and rehabilitation professionals must be aware of these advances and be able to incorporate this knowledge into the practice of rehabilitation medicine. OVERALL ARTICLE OBJECTIVES: (a) To identify major categories of cardiac disease, (b) to elucidate appropriate interventions and support for patients with coronary artery disease, (c) to describe the new interventions available for the treatment of cardiac disease, and (d) to describe the appropriate role of cardiac rehabilitation for people with various forms of cardiac disease.

Adolescent↗

PubMed2006

Cardiopulmonary rehabilitation and cancer rehabilitation. 2. Pulmonary rehabilitation review.

UNLABELLED: Pulmonary rehabilitation includes the rehabilitation of not only patients with respiratory failure in need of ventilatory support but also patients with primary pulmonary disease. New advances in medical management now offer treatment to patients with end-stage emphysema, pulmonary hypertension, and interstitial disease, and the principles of rehabilitation can add both function and quality to the lives of these patients. New surgical approaches and better transplantation outcomes that restore pulmonary function have also been introduced. Rehabilitation professionals need to be aware of these advances and be able to incorporate this knowledge into the practice of rehabilitation medicine. OVERALL ARTICLE OBJECTIVES: (a) To identify major categories of pulmonary disease seen in pulmonary rehabilitation, (b) to know appropriate interventions and support for patients with respiratory failure, (c) to describe the new interventions available for end-stage lung disease, and (d) to describe the appropriate pulmonary rehabilitation for people with pulmonary disease.

Adolescent↗

PubMed2006

Coronary artery disease in masters-level athletes.

UNLABELLED: Screening athletes and advising them regarding exercise are parts of the practice of physical medicine and rehabilitation. Being able to recognize athletes at risk of coronary events is an important part of preparticipation screening. Good guidelines have been developed that let physicians proceed with confidence in screening and in recommending testing for athletes at risk. This review provides the recommended guidelines for physiatrists in practice. OVERALL ARTICLE OBJECTIVES: (a) To recognize risk of coronary disease in athletes, (b) to identify appropriate screening for people at risk, and (c) to interpret test results in people with coronary disease.

Adult↗

PubMed2006

Pulmonary rehabilitation in patients undergoing lung-volume reduction surgery.

UNLABELLED: Chronic obstructive pulmonary disease (COPD) is the most common form of primary pulmonary disability. Few effective treatment options exist for it, but recently, lung-volume reduction surgery (LVRS) has been shown to be effective in selected patients with emphysema. Pulmonary rehabilitation is an integral part of the preparation for and recovery from the procedure and has significant benefit in helping to improve the quality of life and conditioning of patients with COPD who undergo LVRS. OVERALL ARTICLE OBJECTIVES: (a) To describe the role of pulmonary rehabilitation in LVRS, (b) to understand the components of a comprehensive pulmonary rehabilitation program, and (c) to describe the effects of a pulmonary rehabilitation program.

Humans↗

PubMed2005

Increased sympathetic and decreased parasympathetic cardiovascular modulation in normal humans with acute sleep deprivation.

Cardiovascular autonomic modulation during 36 h of total sleep deprivation (SD) was assessed in 18 normal subjects (16 men, 2 women, 26.0 +/- 4.6 yr old). ECG and continuous blood pressure (BP) from radial artery tonometry were obtained at 2100 on the first study night (baseline) and every subsequent 12 h of SD. Each measurement period included resting supine, seated, and seated performing computerized tasks and measured vigilance and executive function. Subjects were not supine in the periods between measurements. Spectral analysis of heart rate variability (HRV) and BP variability (BPV) was computed for cardiac parasympathetic modulation [high-frequency power (HF)], sympathetic modulation [low-frequency power (LF)], sympathovagal balance (LF/HF power of R-R variability), and BPV sympathetic modulation (at LF). All spectral data were expressed in normalized units [(total power of the components/total power-very LF) x 100]. Spontaneous baroreflex sensitivity (BRS), based on systolic BP and pulse interval powers, was also measured. Supine and sitting, BPV LF was significantly increased from baseline at 12, 24, and 36 h of SD. Sitting, HRV LF was increased at 12 and 24 h of SD, HRV HF was decreased at 12 h SD, and HRV LF/HF power of R-R variability was increased at 12 h of SD. BRS was decreased at 24 h of SD supine and seated. During the simple reaction time task (vigilance testing), the significantly increased sympathetic and decreased parasympathetic cardiac modulation and BRS extended through 36 h of SD. In summary, acute SD was associated with increased sympathetic and decreased parasympathetic cardiovascular modulation and decreased BRS, most consistently in the seated position and during simple reaction-time testing.

Adolescent↗

PubMed2005

Aging in polio.

For a disease that was "conquered" some 40 years ago with the onset of effective vaccination, the issues of long-term survivors of paralytic polio as they age continue to present challenges to rehabilitation specialists. Aging with polio is a definition of PPS. There are over a million patients with PPS in the United States. Management has to include the appropriate use of exercises, appropriate bracing and support, and, in the case of bulbar and respiratory symptoms, the appropriate use of speech therapy services and ventilatory support. There are no prospective randomized trials studying the treatment of weakness and fatigue in PPS. Pharmacologic interventions are limited at this time but include anticholinergics for muscle weakness and dopaminergic agents or amantadine to control central fatigue. The pathophysiology of aging with polio is consistent with neuronal loss and denervation lying at the heart of the developing disorder, whereas the central nervous system components of the fatigue syndrome may be related to central changes with neuronal loss in the basal ganglia and reticular-activating system. Many of the survivors of the polio epidemics are in their later retirement years, and their needs will increase as they have other disabilities due to natural aging. Sensitivity to some of the special issues in PPS may help to avoid complications. Polio is an active infection in the third world. Although great strides have been made, the disease is endemic in eight nations and is threatening to spread. The lessons learned in treating PPS now will be useful in years to come as these individuals age and manifest PPS in the future.

Aging↗

PubMed2005

Exercise testing determines survival in patients with diffuse parenchymal lung disease evaluated for lung transplantation.

STUDY OBJECTIVES: Diffuse parenchymal lung disease is associated with a high risk of mortality despite early referral and listing for lung transplantation. We hypothesized that cardiopulmonary exercise test results and the distance walked in 6min (6MWTD) would be associated with survival in patients with diffuse parenchymal lung disease referred for lung transplantation. DESIGN: Retrospective cohort study. SETTING: Tertiary care center. PATIENTS: We included 51 consecutive patients with diffuse parenchymal lung disease who underwent exercise testing after referral to the Lung Transplant Program at the New York Presbyterian Hospital between January 2000 and December 2002. Thirty-three patients were listed, and 7 underwent transplantation during the study period. There were 17 deaths with 1 death post-transplantation. RESULTS: A 6MWTD < 350 m was associated with an increased risk of death (HR = 4.6, 95% CI 1.5-14.2, P = 0.009). Oxygen saturation with unloaded exercise (HR = 0.91, 95% CI 0.84-0.98, P = 0.015) and oxygen consumption at peak exercise adjusted for weight (HR = 0.88, 95% CI 0.79-0.99, P = 0.039) were also associated with the risk of death. A patient with oxygen saturation <95% during unloaded exercise had a 75% chance of dying on the list for transplantation. A patient with 6MWTD < 350 m had a 67% chance of dying on the list. CONCLUSIONS: Cardiopulmonary exercise test parameters and the 6MWTD were associated with the risk of death. Measures during exercise may be useful for determination of prognosis and for prioritizing patients with diffuse parenchymal lung disease for lung transplantation.

Adult↗

PubMed2004

The effect of ventilation on spectral analysis of heart rate and blood pressure variability during exercise.

Heart rate variability (HRV) and systolic blood pressure variability (BPV) during incremental exercise at 50, 75, and 100% of previously determined ventilatory threshold (VT) were compared to that of resting controlled breathing (CB) in 12 healthy subjects. CB was matched with exercise-associated respiratory rate, tidal volume, and end-tidal CO(2) for all stages of exercise. Power in the low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, >0.15-0.4 Hz) for HRV and BPV were calculated, using time-frequency domain analysis, from beat-to-beat ECG and non-invasive radial artery blood pressure, respectively. During CB absolute and normalized power in the LF and HF of HRV and BPV were not significantly changed from baseline to maximal breathing. Conversely, during exercise HRV, LF and HF power significantly decreased from baseline to 100% VT while BPV, LF and HF power significantly increased for the same period. These findings suggest that the increases in ventilation associated with incremental exercise do not significantly affect spectral analysis of cardiovascular autonomic modulation in healthy subjects.

Adult↗

PubMed2004

Reproducibility of heart rate and blood pressure variability in patients with chronic obstructive pulmonary disease.

Wide variations in respiratory rate and hypoxic stimulation of chemoreceptors may produce unreliable autonomic results in patients with COPD. We studied the reproducibility of two consecutive measurements of heart rate variability (HRV) and blood pressure variability (BPV) by time frequency analysis in patients with COPD while controlling respiratory rate and oxygen hemoglobin saturation (SaO(2)). Reproducibility was assessed by paired t-tests and correlation analyses between repeated measures. Correlation analyses of the log transformed low (LF) and high frequency (HF) HRV were x 11.5 +/- 1.1 in measurement A and x 11.5 +/- 1.0 in measurement B (r = 0.89, p < 0.0001), and x 10.5 +/- 1.1 in measurement A and x 10.6 +/- 1.1 in measurement B (r = 0.89, p < 0.0001) respectively. The log transformed LF and HF BPV were x 4.9 +/- 1.3 in measurement A and x 5.3 +/- 0.9 in measurement B (r = 0.70, p < 0.0002), and x 6.4 +/- 1.3 in measurement A and 6.6 +/- 1.2 in measurement B (R = 0.71 p < 0.0001) respectively. In conclusion, time frequency analysis of HRV and BPV is reproducible and reliable in patients with COPD while controlling their respiratory rate and oxygen hemoglobin saturation. Reproducibility of these measurements may allow for a non-invasive evaluation of autonomic tone in response to treatments in COPD patients.

Aged↗

PubMed2004

Supplemental oxygen increases arterial stiffness in chronic obstructive pulmonary disease.

STUDY OBJECTIVES: Recently, we demonstrated significantly improved baroreflex sensitivity (BRS) and autonomic balance after 31% supplemental oxygen (SuppO2) in resting patients with chronic obstructive pulmonary disease (COPD). In order to investigate whether peripheral arterial stiffness changes may play a role, we evaluated changes in peripheral arterial stiffness and BRS after SuppO2. DESIGN: Single blinded crossover design. SETTING: Pulmonary exercise testing laboratory. PARTICIPANTS: Seventy subjects with moderate to severe COPD. INTERVENTIONS: We measured arterial vascular stiffness using the augmentation index via contour analysis of the radial pulse obtained from applanation tonometry. BRS was derived using the sequence method before and after treatments with compressed air (CA) and 30% SuppO2 in 70 individuals with COPD via a counterbalanced crossover design. RESULTS: Paired t-tests indicated significant differences in oxygen saturation (SaO2) following SuppO2 when compared to CA (mean 96.0+/-2.0% SuppO2 versus mean 92.6+/-3.6% CA, P<0.001). BRS was significantly greater following SuppO2 compared to CA (mean 3.5+/-2.3 ms/mmHg SuppO2 versus mean 3.1+/-2.1 CA ms/mmHg, P<0.03). Vascular stiffness was significantly increased with SuppO2 when compared with CA (mean 13.3+/-6.1% SuppO2 versus mean 10.8+/-4.9% CA, P<0.001). CONCLUSIONS: Our findings indicate that oxygen supplementation ameliorates BRS by changes in vasomotor activity. The amelioration of the BRS into a more normal range is a move towards the restoration of more normal physiology.

Aged↗

PubMed2003

Low arterial compliance in young African-American males.

Hypertension remains a common public health challenge because of its prevalence and increase in co-morbid cardiovascular diseases. Black males have disproportionate pathophysiological consequences of hypertension compared with any other group in the United States. Alterations in arterial wall compliance and autonomic function often precede the onset of disease. Accordingly, our purpose was to investigate whether differences exist in arterial compliance and autonomic function between young, healthy African-American males without evidence of hypertension and age- and gender-matched non-African-American males. All procedures were carried out noninvasively following rest. Arterial compliance was calculated as the integrated area starting at the well-defined nadir of the incisura of the dicrotic notch to the end of diastole of the radial artery pulse wave. Power spectral analysis of heart rate and blood pressure variability provided distributions representative of parasympathetic and sympathetic modulations and sympathovagal balance. Baroreflex sensitivity (BRS) was calculated using the sequence method. Thirty-two African-American and twenty-nine non-African-American males were comparable in anthropometrics and negative family history of hypertension. t-Tests revealed lower arterial compliance (5.8 +/- 2.4 vs. 8.6 +/- 4.0 mmHg. s; P = 0.0017), parasympathetic modulation (8.9 +/- 1.1 vs. 9.7 +/- 1.1 ln ms2; P = 0.0063), and BRS (13.7 +/- 7.3 vs. 21.1 +/- 8.5 ms/mmHg; P = 0.0007) and higher sympathovagal balance (2.9 +/- 3.2 vs. 1.5 +/- 1.1; P = 0.03) in the African-American group. In summary, differences exist in arterial compliance and autonomic balance in African-American males. These alterations may be antecedent markers of disease and valuable in the detection of degenerative cardiovascular processes in individuals at risk.

Adult↗

PubMed2003

Evaluation of blood pressure and baroreflex sensitivity by radial artery tonometry versus finger arteriolar photoplethysmography.

BACKGROUND: Published normative data of noninvasive blood pressures (BPs) and autonomic modulations have been primarily derived from the finger arteriole using the Finapres (Ohmeda Co., Englewood, CO), a device that is no longer manufactured. Currently, beat-to-beat BP are obtained from the radial artery using the Colin tonometer. METHODS: We compared BP and autonomic parameters in a crossover design between the two devices in 29 subjects during seated rest and a 0.1-Hz breathing protocol. In addition, we tested whether finger arteriolar BP differences were due to pressure changes exerted by the radial tonometer. RESULTS: Uniformly, BP measured at the radial artery were significantly higher than those from the finger arteriole. Radial BP (106 +/- 19.5 mm Hg) were higher than finger arteriolar BP (95.8 +/- 13.7 mm Hg) (P <.005). Tonometric baroreflex sensitivity (BRS) (24.0 +/- 18 msec/mm Hg) was higher compared to photoplethysmographic BRS (12.0 +/- 7.7 msec/mm Hg; P <.0003). Systolic BP (radial artery) (115 +/- 25 mm Hg) were higher compared to finger arteriolar BP (97.7 +/- 19 mm Hg; P <.0025) during breathing, as was BRS (25.9 +/- 11.6 msec/mm Hg v 21.5 +/- 11.6 msec/mm Hg; P <.05). Differences in the low frequency systolic BP (LF(SBP)), representative of sympathetic vasomotor modulation, between the two methods, whether absolute, normalized, or log-transformed were not observed. CONCLUSIONS: There were no differences in arteriolar BP values in the presence or absence of radial artery tonometric pressure. These findings indicate that differences exist in systolic BP and BRS using the tonometer (radial artery) versus the Finapres (Ohmeda Co.) (finger arteriole). Furthermore, these differences are not due to pressure exerted by the radial artery tonometer that supplies blood to the finger arteriole.

Adult↗

PubMed2003

High-frequency modulation of heart rate variability during exercise in patients with COPD.

STUDY OBJECTIVES: To evaluate cardiac autonomic modulation in patients with COPD during peak exercise. METHODS: Fifty-three patients with COPD (mean FEV(1), 35% predicted [SD, 11% predicted]; mean PaO(2), 68 mm Hg [SD, 11 mm Hg]; mean PaCO(2), 40 mm Hg [SD, 7 mm Hg]; mean age, 61 years [SD, 10 years]; 26 women and 27 men) and 14 healthy control subjects aged 60 years (SD, 8 years) [seven women and seven men] were studied at rest and during ramped bicycle ergometry to their volitional peak. Patients were not receiving autonomic medications other than inhaled beta-agonist agents and/or anticholinergic agents. Control subjects were not receiving any medications. Cardiac autonomic modulation was assessed via time-frequency analysis (Wigner-Ville) of ECG-derived heart rate variability as the power in the low-frequency (LF) band (ie, 0.04 to 0.15 Hz) and the high-frequency (HF) band (ie, > 0.15 to 0.4 Hz) averaged from > 3 min at rest and minutes 2 through 5 of their exercise period. RESULTS: Patients with COPD had a significantly increased mean, ln-transformed HF band from rest to peak exercise (9.9 ms(2) [SD, 1.4 ms(2)] vs 10.7 ms(2) [SD, 1.4 ms(2)], respectively; p < 0.01), while the HF band was unchanged for the control group (10.7 ms(2) [SD, 1.5 ms(2)] vs 10.4 ms(2) [1.3 ms(2)], respectively; difference not significant). The mean ln-transformed LF band was significantly increased from rest to peak exercise in patients with COPD (10.9 ms(2) [SD, 1.5 ms(2)] vs 11.5 ms(2) [SD, 1.4 ms(2)], respectively; p < 0.01) and in control subjects (10.9 ms(2) [SD, 1.5 ms(2)] vs 11.5 ms(2) [SD, 1.3 ms(2)], respectively; p < 0.01). The mean LF/HF ratio was significantly decreased from rest to peak exercise in patients with COPD (3.1 [SD, 1.5] vs 2.5 [SD, 1.0], respectively; p < 0.01) and was increased in control subjects (1.9 [SD, 0.8] vs 2.4 [1.0], respectively; p < 0.01). When expressed in normalized units ([absolute power of the components]/[total power - very low frequency power] x 100), the HF band was again significantly greater during peak exercise than at rest in the patients with COPD and was unchanged during peak exercise for the control group. Autonomic changes were not significantly correlated with age, gender, body mass index, spirometry, lung volumes, resting gas exchange, or oxygen saturation during exercise. CONCLUSION: These data suggest that, in contrast to control subjects, the balance of sympathetic to parasympathetic cardiac modulation decreases in patients with COPD during maximal volitional exercise.

Aged↗

PubMed2002

Arterial stiffness increases during obstructive sleep apneas.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) appears to be an independent risk factor for diurnal systemic hypertension, but the specific biologic markers for this association have not been well established. Increased arterial stiffness is an important measure of increased left ventricular load and a predictor of cardiovascular morbidity and may precede the onset of systemic hypertension in humans. However, arterial stiffness has not been measured in association with obstructive apneas in patients with OSA, nor related to systemic blood pressure (BP) activity in this setting. Our objective was to test the hypothesis that arterial stiffness may be utilized as a sensitive measure of arterial vasomotor perturbation during obstructive events in patients with OSA, by demonstrating that (1) arterial stiffness increases acutely in association with obstructive apnea and hypopnea, and that (2) such increased stiffness may occur in the absence of acute BP increase. DESIGN: Prospective, cross-sectional. SETTING: A tertiary-care university-based sleep and ventilatory disorders center. PATIENTS: Forty-four normo- and hypertensive adult patients (11 women, 33 men) with polysomnographically diagnosed moderate to severe OSA. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Beat-to-beat BP was recorded from the radial artery by applanation tonometry during nocturnal polysomnography. Arterial augmentation index (AAI), a measure of arterial stiffness, was calculated as the ratio of augmented systolic BP (SBP) to pulse pressure and expressed as a percentage for the following conditions: awake, the first 10 ("early apnea") and last 10 ("late apnea") cardiac cycles of obstructive events, and the first 15 cardiac cycles following apnea termination ("post apnea"). Mean AAI (+/-SD) for the group was significantly increased during NREM sleep from early apnea to late apnea (12.02 +/- 2.70% vs 13.35 +/- 3.54%, p<0.05, ANOVA). During REM (analyzed in 20 patients), MI again significantly increased from early apnea to late apnea (11.75 +/- 2.81% vs 13.43 +/- 4.97%). Conversely, neither mean SBP nor mean arterial BP was significantly changed from early apnea to late apnea in NREM (SBP 130 +/- 14 mmHg vs 129 +/- 14 mmHg) or REM (SBP 128 +/- 22 mmHg vs 127 +/- 21 mmHg). CONCLUSIONS: Arterial stiffness increases acutely during obstructive apneas in both NREM and REM sleep, in the absence of measurable BP change. These data suggest that arterial stiffness may be a sensitive measure of acute arterial vasomotor perturbation in this setting and may have implications concerning cardiovascular sequelae in patients with OSA.

Adult↗