Synthesis of radiolabeled congeners of the carbomers: (14)C-labeled poly(acrylic acid)s

A general method for the synthesis of (14)C-acrylic acid is described in detail. The material is used for the synthesis of a range of radiolabeled poly(acrylic acid)s in which the (14)C-label forms an integral part of the polymer backbone. The chemical structure of the synthesized polymers is examined in the light of spectroscopic data, molecular weight determinations, and rheological studies.

Amplitude Apodizers Encoded onto Fresnel Lenses Implemented on a Phase-Only Spatial Light Modulator

We show that both a lens and a nonuniform amplitude transmission filter can be encoded simultaneously onto a twisted nematic liquid-crystal spatial light modulator (SLM) working in the phase-only mode. The inherent equivalent apodization that is due to the pixelated structure of the SLM is compensated for. In addition, different types of nonuniform transmission pupil such as transverse apodizing, transverse hyperresolving, and axial hyperresolving (multifocusing) filters are implemented. The excellent agreement between numerical and experimental results shows the capability of this method to encode amplitude apodizers on a phase-only SLM.

Polarization beam splitters using polarization diffraction gratings

We report a polarization beam splitter that uses polarization gratings written onto a zero-twist nematic liquid-crystal display. We show three configurations. The first two separate the diffracted light into two orthogonally polarized orders that are either linearly or circularly polarized. In the third configuration, we demonstrate a novel case for which the output is separated into two nonorthonormal polarization states. One component is linearly polarized and the second is circularly polarized.

Genetic and metabolic analysis of the first adult with congenital disorder of glycosylation type Ib: long-term outcome and effects of mannose supplementation

We report the diagnosis and follow-up of two sibs reported in 1980 with recurrent venous thromboses and protein-losing enteropathy; one sib with biopsy-proven hepatic fibrosis died at age 5. The combination of symptoms was suggestive of the recently characterized congenital disorder of glycosylation type Ib (CDG-Ib), which is caused by a deficiency of the enzyme phosphomannose isomerase (PMI). An abnormal serum transferrin isoelectric focusing (IEF) pattern and a reduced PMI activity confirmed the diagnosis of CDG-Ib. Furthermore, mutational analysis of the MPI gene revealed two missense mutations, 419 T --> C (I140T) and 636 G --> A (R219Q), a single base substitution in intron 5, 670 + 9G --> A, as well as a polymorphism 1131A --> C (V377V) in both sibs. The surviving 33-year-old sib has had no further symptoms following childhood. Short-term low-dose oral mannose supplementation improved her transferrin IEF pattern and normalized her antithrombin III activity, further substantiating the beneficial effect of mannose in CDG-Ib. When her mannose blood level was measured, she showed a lower steady-state level but a faster mannose clearance rate. These results suggest that the clinical manifestations of PMI deficiency, although serious in childhood, can improve with age, even without mannose therapy, and allow for a normal adult life. However, the long-term prognosis may vary from patient to patient.

An investigation of mucus/polymer rheological synergism using synthesised and characterised poly(acrylic acid)s

A range of poly(acrylic acid)s with different average degrees of polymerisation and cross-linking densities were synthesised using a solution polymerisation process. The rheological characteristics of aqueous dispersions of these materials and those of mixtures with homogenised pigs gastric mucus were investigated using dynamic oscillatory rheology, and compared to the known mucoadhesive Carbopol 934P. From the storage moduli, the rheological synergy and relative rheological synergy were calculated, and the effects of concentration and pH on this considered. Generally, the larger the molecular weight (and degree of cross-linking), the greater the rheological synergy, with Carbopol 934P giving the most pronounced effect. Rheological synergy was seen to be concentration-dependent, and a maximum concentration to produce an optimum effect was evident. Acid pHs were seen to favour synergy, although in marked contrast to previous literature reports, the optimum mucus-polymer interaction was not observed at the half ionised value (pH = pKa) but at pH regimes that were unique to each polymer type. This could be influenced by the structural constrains imposed on potential hydrogen bonded interactions. It was concluded that synthesising poly(acrylic acid)s with better defined physicochemical properties than commercially available polymers will advance the study of the phenomenon of rheological synergy.

Surgical technique for installing an eight-channel neuroprosthesis for standing

A standardized surgical procedure to implant an eight-channel functional neuromuscular stimulation system in the lower extremities for standing, exercise, and transfers for individuals with spinal cord injury has been developed. The implanted components include: (1) one eight-channel receiver-stimulator, (2) epimysial electrodes, (3) intramuscular electrodes, and (4) inline connectors. The development process included identifying the target muscle set for electrode placement and the corresponding surgical approaches, determining the stages of the surgical procedure, and assessing the effectiveness and stability of the implanted neuroprosthesis. The bilateral muscle set consists of the vastus lateralis, the gluteus maximus, the semimembranosus, and the erector spinae. Surgical approaches to the nerve entry points were developed through a series of cadaveric studies and intraoperative tests. Electrode placement is related to bony landmarks and based on standard orthopaedic approaches. The components of the neuroprosthesis are installed in one surgical session, with three stages. This procedure has been applied successfully in seven individuals, resulting in strong, isolated stimulated contractions adequate to raise and lower the body, maintain standing with a walker, and perform pivot transfers. The standardized surgical procedure is repeatable and teachable and will be used in upcoming multicenter clinical trials of the implanted neuroprosthesis.

Major coronary artery anomalies in a pediatric population: incidence and clinical importance

OBJECTIVES

We sought to prospectively determine the incidence and clinical significance of major coronary artery anomalies in asymptomatic children using transthoracic two-dimensional echocardiography.

BACKGROUND

Anomalous origins of the left main coronary artery (ALMCA) from the right sinus of Valsalva or anomalous origins the right coronary artery (ARCA) from the left sinus are rarely diagnosed in children and can cause sudden death, especially in young athletes. Because most patients are asymptomatic, the diagnosis is often made post mortem. No study to date has prospectively identified anomalous coronary arteries in asymptomatic children in the general population.

METHODS

After serendipitously identifying an index case with ALMCA, we examined proximal coronary artery anatomy in children with otherwise anatomically normal hearts who were referred for echocardiography. In those diagnosed with ALMCA or ARCA, we performed further tests.

RESULTS

Within a three-year period, echocardiograms were obtained in 2,388 children and adolescents. Four children (0.17%) were identified with anomalous origin of their coronary arteries, and angiograms, exercise perfusion studies and/or stress tests were then performed. One ARCA patient had decreased perfusion in the right coronary artery (RCA) perfusion area and showed ventricular ectopy on electrocardiogram (ECG) at rest that diminished but did not resolve with exercise. A second patient with ALMCA had atrial tachycardia immediately after exercise, with inferior and lateral ischemic changes on ECG and frequent junctional and/or ventricular premature complexes both at rest and recovery.

CONCLUSIONS

This study demonstrates that although anomalous origins of coronary arteries are rare in asymptomatic children, the prevalence is greater than that found in other prospective studies. Ischemia can occur with both ALMCA and ARCA even though patients remain asymptomatic. Because of the high risk of sudden cardiac death, aggressive surgical management and close follow-up are necessary.

Fully complex synthetic discriminant functions written onto phase-only modulators

Synthetic discriminant functions (SDF's) are an effective tool for pattern-recognition applications. However, their experimental implementation is difficult because of the difficulty in writing full complex modulation functions onto spatial light modulators (SLM's) with restricted coding domains. Iterative methods are required for the implementation of SDF filters in real SLM's. A great deal of experimental research has been done with phase-only filters because they can be successfully implemented with liquid-crystal SLM's. We have recently introduced a technique for encoding arbitrary amplitude information onto the phase-only filter, thus allowing us to encode an arbitrary complex function onto a phase-only SLM. We apply this technique to the generation of arbitrary complex SDF filters, thus avoiding the necessity of iterative algorithms. We examine the discrimination capabilities of fully complex SDF filters designed with different parameters and constraints. Experimental results obtained with liquid-crystal SLM's are included.

Inherent apodization of lenses encoded on liquid-crystal spatial light modulators

Focusing diffractive optical elements encoded in liquid-crystal spatial light modulators yields an inherent equivalent apodization of the focused spot as a result of the pixelated nature of these devices and the finite extent of each pixel. We present a theoretical explanation for and experimental evidence of this effect. We demonstrate an experimental procedure for measuring the apodization and a method to compensate for this effect.

Prospective analysis of psychosocial outcomes in breast reconstruction: one-year postoperative results from the Michigan Breast Reconstruction Outcome Study

In the past decade, changing attitudes toward breast reconstruction among both patients and providers have led a growing number of women to seek breast reconstruction after mastectomy. Although investigators have documented the psychological, social, emotional, and functional benefits of breast reconstruction, little research has evaluated the effects of procedure choice on these outcomes. The current study prospectively evaluated and compared psychosocial outcomes for three common options for mastectomy reconstruction: tissue expander/implant, pedicle TRAM, and free TRAM techniques. In a prospective cohort design, patients undergoing postmastectomy reconstruction for the first time with expander/implant, pedicle TRAM, or free TRAM procedures were recruited from 12 centers and 23 plastic surgeons in the United States and Canada. Before reconstruction and at 1 year after reconstruction, patients were evaluated by a battery of questionnaires consisting of both generic and condition-specific surveys. Outcomes assessed included emotional well-being, vitality, general mental health, social functioning, functional well-being, social well-being, and body image. Baseline (preoperative) scores and the change in scores (the difference between postoperative and preoperative scores) were compared across procedure types using t tests and analysis of covariance. Preoperative and 1-year postoperative surveys were obtained from 273 patients. Procedure type was reported in 250 patients, of whom 56 received implant reconstructions, 128 pedicle TRAM flaps, and 66 free TRAM flaps. A total of 161 immediate and 89 delayed reconstructions were performed. Among women receiving immediate reconstruction, significant improvements were observed in all psychosocial variables except body image. However, no significant effects of procedure type on these changes over time existed. Similarly, delayed reconstruction patients had significant increases in emotional well-being, vitality, general mental health, functional well-being, and body image. Although the choice of reconstructive technique did not significantly impact most of these outcomes, significant differences existed among procedure types for three psychosocial subscales. Patients undergoing delayed expander/implant reconstructions reported greater improvements in vitality and social well-being relative to women receiving delayed TRAM procedures. By contrast, delayed TRAM patients noted significantly greater gains in body image compared with women choosing delayed expander-implant reconstruction. The authors conclude that both immediate and delayed breast reconstructions provide substantial psychosocial benefits for mastectomy patients. Although the choice of reconstructive procedure does not seem to significantly affect improvements in psychosocial status with immediate reconstruction, our data suggest that procedure type does have a significant effect on gains in vitality and body image for women undergoing delayed reconstruction.

Determinants of patient satisfaction in postmastectomy breast reconstruction

In today's increasingly competitive health care marketplace, consumer satisfaction has become an important measure of quality. Furthermore, measures of satisfaction with treatment inteerventions are influential factors in determining patients' and payers' choices of health care. This study sought to evaluate satisfaction with postmastectomy breast reconstruction and to assess the effects of procedure type and timing on patient satisfaction. As part of the Michigan Breast Reconstruction Outcome Study, patients undergoing first-time mastectomy reconstruction were prospectively evaluated, including cohorts of women choosing expander/implant, pedicle TRFAM flap, and free TRAM flap procedures. Preoperatively and 1 year postoperatively, participants completed a questionnaire that collected a variety of health status information. The postoperative questionnaire had an additional seven items assessing both general satisfaction with reconstruction (five items) and aesthetic satisfaction (two items) as separate subscales. Patients were asked to respond to each item using a five-point Likert scale. Item responses ranged from 1, indicating high satisfaction, to 5, reflecting low satisfaction. In the data analysis, only patients responding with a 1 or 2 for all of the items within a subscale were classified as "satisfied" for the subscale. To assess the effects of procedure type (implant, pedicle TRAM flap, and free TRAM flap) and timing (immediate versus delayed) on satisfaction and to control for possible confounding effects from other independent variables, multiple logistic regression was employed. In our analysis, odds ratios and associated 95 percent confidence intervals were calculated for each independent variable in the regression. Statistical significance was designated at the p < or = 0.05 level. A total of 212 patients were followed during the period of 1994 to 1997, including 141 immediate and 71 delayed reconstructions. The study population consisted of 49 expander/implant, 102 pedicle TRAM flap, and 61 free TRAM flap reconstruction patients. The analysis showed a significant association between procedure type and patient satisfaction. TRAM flap patients (both free and pedicle) appeared to have significantly greater general and aesthetic satisfaction compared with expander/implant patients (p = 0.03 and 0.001, respectively). Furthermore, pedicle TRAM flap patients were more aesthetically satisfied than those with free TRAM flaps (p = 0.072). The other independent variables of age and procedure timing did not appear to significantly affect either general or aesthetic satisfaction. However, preoperative physical activity was positively correlated with general satisfaction at the p = 0.034 level. The choice of procedure seems to have a significant effect on both aesthetic and general patient satisfaction with breast reconstruction. In this study, autogenous tissue reconstructions produced higher levels of patient aesthetic and general satisfaction compared with implant techniques. Pedicle and free TRAM flap patients do not seem to differ significantly in general satisfaction. However, women receiving pedicle TRAM flaps reported greater aesthetic satisfaction compared with patients undergoing free TRAM flaps. Furthermore, patient age and procedure timing may not have an effect on patient satisfaction with breast reconstruction.

Comparison of total body urea production potential with total body carbamoyl phosphate synthetase (CPS-1) activity in newborn piglets infused with alanine at 50% of resting energy expenditure for 36 hours

The calculated rate of urea production [U(p); mmol urea/(h. kg(0. 75))], based on urinary urea-N (UUN) excretion and changes in total body urea-N, was compared with the calculated total body V(max) of carbamoyl phosphate synthetase (CPS-1) of 24 neonatal piglets from four treatments as follows: 6 h baseline control (n = 8), 18 h of alanine intravenously (IV) at 50% of resting energy expenditure (REE; n = 4), 36 h of alanine IV at 50% of REE (n = 6), or 36 h of glucose IV at 50% of REE (n = 6). The following significant increases from baseline were seen in piglets infused with alanine for 36 h: 1) UUN excretion [10.6 +/- 5.9 mg N/(h. kg(0.75)) to 53.2 +/- 11.1]; 2) BUN concentrations (9.1 +/- 3.0 mmol urea N/L to 51.2 +/- 7.0); 3) calculated urea production [0.34 +/- 0.21 mmol urea/(h. kg(0.75)) to 2.39 +/- 0.53]; and 4) CPS-1 V(max) [2.0 +/- 0.81 mmol citrulline/(h. kg (0.75)) to 4.4 +/- 1.5], (P < 0.05). With the exception of CPS-1 activity, significant decreases from baseline were seen in these values in piglets infused with glucose for 36 h (P < 0.05). Comparison of calculated urea production with calculated total body CPS-1 V(max) at baseline, 18 or 36 h after the start of infusion of alanine or glucose revealed a positive relationship (slope = 0.263; P < 0.002). At all enzyme activities, infusion of alanine resulted in a significant increase in the rate of urea production compared with controls (P < 0.001). Total body CPS-1 activity varied from 1.8 to 5.8 times that of urea production, suggesting that CPS-1 did not limit urea production.

Urea production is increased in neonatal piglets infused with alanine at 25, 50, and 75% of resting energy needs

To study the ability of neonatal piglets to metabolize a nitrogen load and excrete it as urea, 12 newborn piglets, 6 small (0.99 +/- 0. 16 kg; expt. 1) and 6 large (1.86 +/- 0.16 kg; expt. 2), were infused intravenously with alanine (n = 8; 4 large, 4 small; treatment) or glucose (n = 4; 2 large, 2 small; control) at equal ATP equivalents, supplying 25-75% of the resting energy requirements of the piglet over 18 h. To adjust for differences in the baseline urinary urea nitrogen excretion, blood urea nitrogen (BUN) and estimated urea production between groups, the absolute changes from baseline to maximum value for piglets infused with alanine, and from baseline to the 24-h value for piglets infused with glucose were evaluated statistically. There were no differences (0.1 < P < 0.3) in the absolute changes from baseline to maximum values of urinary urea nitrogen, BUN or estimated urea production between small [18.6 +/- 3.8 mg N/(h. kg(0.75)); 19.1 +/- 2.2 mmol N/L; 2.7 +/- 1.2 mmol N/(h. kg(0.75)), respectively] and large [23.6 +/- 7.6 mg N/(h. kg(0. 75)); 21.6 +/- 3.3 mmol N/L; 3.7 +/- 1.5 mmol N/(h. kg(0.75)), respectively] piglets infused with alanine. Differences in the changes from baseline were detected between alanine and glucose (P = 0.001) infusions. Small piglets required more time (P < 0.005) for BUN to maximize after initiation of the alanine infusion, suggesting that small piglets require more time to process a nitrogen load. Infusion of alanine resulted in at least a threefold increase from baseline in the rate of calculated urea production, suggesting that neonatal piglets, small or large, have reserve capacity to metabolize nitrogen and excrete it as urea.

A controlled NO-releasing compound: synthesis, molecular structure, spectroscopy, electrochemistry, and chemical reactivity of R,R,S,S-trans-[RuCl(NO)(cyclam)]2+(1,4,8,11-tetraazacyclotetradecane)

The synthesis of trans-[RuCl(NO)(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) can be accomplished by either the addition of cyclam to K2[RuCl5NO] or by the addition of NO to trans-[RuCl(CF3SO3)(cyclam)](CF3-SO3). Crystals of trans-[RuCl(NO)(cyclam)](ClO4)2 form in the monoclinic space group P2(1)/c, with unit cell parameters of a = 7.66500(2) A, b = 24.7244(1) A, c = 16.2871(2) A, beta = 95.2550(10) degrees, and Z = 4. One of the two independent molecules in the unit cell lies disordered on a center of symmetry. For the ion in the general position, the Ru-N and N-O bond distances and the [Ru-N-O]3+ bond angle are 1.747(4) A, 1.128(5) A, 178.0(4) degrees, respectively. In both ions, cyclam adopts the (R,R,S,S) configuration, which is also consistent with 2D COSY 1H NMR studies in aqueous solution. Reduction (E degree = -0.1 V) results in the rapid loss of Cl- by first-order kinetics with k = 1.5 s-1 and the slower loss of NO (k = 6.10 x 10(-4) s-1, delta H++ = 15.3 kcal mol-1, delta S++ = -21.8 cal mol-1 K-1). The slow release of NO following reduction causes trans-[RuCl(NO)(cyclam)]2+ to be a promising controlled-release NO prodrug for vasodilation and other purposes. Unlike the related complex trans-[Ru(NO)(NH3)4(P(OEt)3)](PF6)2, trans-[RuCl(NO)(cyclam)]Cl2 is inactive in modulating evoked potentials recorded from mice hippocampal slices probably because of the slower dissociation of NO following reduction.

Effects of single dose, postinduction dexamethasone on recovery after cardiac surgery

BACKGROUND

Corticosteroids have been recommended to facilitate rapid recovery after cardiac surgery. We previously reported that dexamethasone given after induction of anesthesia decreases the incidence of postoperative shivering. We performed a post hoc analysis of the data obtained during that study, focusing on secondary outcomes.

METHODS

A total of 235 adult patients undergoing elective coronary or valvular heart surgery were randomized to receive dexamethasone 0.6 mg/kg or placebo after induction of anesthesia. Patients who had pharmacologically treated diabetes mellitus, had hypersensitivity to dexamethasone, or were receiving treatment with corticosteroids were excluded.

RESULTS

We found that, compared with placebo, patients receiving dexamethasone were more likely to remain tracheally intubated for 6 hours or less (26.4% vs 10.0%, p = 0.020) and had a lower incidence of early postoperative fever (20.2% vs 36.8%, p = 0.009) and new-onset atrial fibrillation during the first 3 days postoperatively (18.9% vs 32.3%, p = 0.027). However, we could not demonstrate a statistical difference in the intensive care unit or hospital length of stay, or in overall morbidity and mortality. The dexamethasone-treated patients were also more likely to have a higher blood glucose on admission to the intensive care unit (186 mg/dL vs 143 mg/dL, p = 0.012).

CONCLUSIONS

Dexamethasone facilitates early tracheal extubation and is associated with a lower incidence of early postoperative fever and new-onset atrial fibrillation. Apart from a treatable decreased glucose tolerance, dexamethasone treatment was not shown to affect morbidity or mortality significantly.

Vibrational angioplasty and hydrophilic guidewires in the treatment of chronic total coronary occlusions

PURPOSE

To study the efficacy and safety of vibrational angioplasty versus hydrophilic guidewires for recanalizing chronic total occlusions (CTOs) of the coronary arteries.

METHODS

In a retrospective study, 99 patients with old (>3 months) CTOs resistant to conventional techniques were treated either with vibrational angioplasty (group A, n = 72) or 0.014-inch hydrophilic guidewires (group B, n = 27). The selection of the technique (vibrational angioplasty or hydrophylic guidewires) was dependent only upon device availability. A variety of guidewires were employed in conjunction with vibrational angioplasty.

RESULTS

The crossing success rates in groups A and B were 86.1% (62/72) and 55.5% (15/27) (p < 0.05), with final procedural success rates of 75% (54/72) and 44.4% (12/27) (p < 0.01), respectively. The main reasons for failure were inability to cross the lesion with a guidewire (10/18 in group A and 12/15 in group B) and large dissections resulting in vessel closure (2/18 in group A and 2/15 in group B). Three major complications were seen, 2 in group A and 1 in group B. Three vessel perforations were reported in group A. Both techniques needed prolonged fluoroscopy times.

CONCLUSIONS

Vibrational angioplasty was more successful in treating CTOs compared to hydrophilic guidewires and had similar complication rates (most without clinical sequelae).

Two-dimensional polarization encoding with a phase-only liquid-crystal spatial light modulator

We show how to two dimensionally encode the polarization state of an incident light beam using a parallel-aligned liquid-crystal spatial light modulator (LCSLM). Each pixel of the LCSLM acts as a voltage-controlled wave plate and can be programmed over a 2pi phase range at a wavelength of 514.5 nm. Techniques are reviewed for either rotating the major axis of elliptically polarized light or for converting an input linearly polarized beam into an arbitrary elliptically polarized beam. Experimental results are demonstrated in which we generate various two-dimensional spatial patterns of polarized light. Several potential applications are suggested. We also report an unexpected edge-enhancement effect that might be useful in image processing applications.

Image processing with the radial Hilbert transform: theory and experiments

The Hilbert transform is useful for image processing because it can select which edges of an input image are enhanced and to what degree the edge enhancement occurs. However, the transform operation is one dimensional and is not applicable for arbitrarily shaped two-dimensional objects. We introduce a radially symmetric Hilbert transform that permits two-dimensional edge enhancement. We implement one-dimensional, two-dimensional, and radial Hilbert transforms with a programmable phase-only liquid-crystal spatial light modulator. Experimental results are presented.

Localization of chromophore absorption signals in TEM with an improved prism-mirror-prism filter

A corrected prism-mirror-prism electron energy filter with curved entrance and exit faces was designed and incorporated into a Zeiss EM902 transmission electron microscope. The installation of the new filter required little modification to the existing microscope geometry and electronics. The filter had an energy resolution of 1.1 eV over the full image plane (acceptance half angle 10 mradian). The improved energy resolution was applied in studies of the low electron energy loss region that includes molecular orbital excitations or chromophore energy absorptions. Chromophore signal behaviour under electron irradiation was characterized using embedded crystals of hematin and of the dye mercury orange. Images of these crystals confirmed the expected decrease in signal intensity on shifting the selected energy loss from the region of molecular orbital excitations (less than approximately 5 eV) to higher energy losses. Electron irradiation-induced fading of the chromophore signal from hematin and mercury orange yielded similar 1/e dose values of 1.1 x 10(5) e(-) nm(-2) and 1.4 x 10(5) e(-) nm(-2) respectively. In a cellular context, chromophore signals were obtained from energy-filtered images of RIF-1 cell sections containing the photosensitizer chlorin e6 and from sections of BS-C-1 cells with cytoskeletal labelling via FITC-conjugated antibodies. The respective signals were extracted using a dose-dependent method or a shift in selected energy. Chromophore signal distributions were in agreement with fluorescence light microscopic images, but provided detail at higher spatial resolution.

Cardio-respiratory responses to rowing ergometry and treadmill exercise soon after myocardial infarction

PURPOSE

The aim of this study was to compare the cardio-respiratory differences between rowing ergometry and treadmill exercise in beta-blocked men participating in exercise rehabilitation soon after myocardial infarction (postMI).

METHODS

Eleven males all receiving beta-blockade medication were measured for oxygen consumption (VO2), respiratory exchange ratio (RER), and rating of perceived exertion (RPE) at individualized submaximal exercise target heart rates (THR) during 6 min of exercise on each of a motorized treadmill and a rowing ergometer 2-6 wk (4.9 +/- 1.4) postMI.

RESULTS

The mean THR of the group, predetermined from an exercise ECG stress test, was 107 +/- 16 beats x min(-1). No significant difference was found between rowing versus treadmill VO2 (19.4 +/- 3.2 vs 19.7 +/- 4.2 mL x kg(-1) x min(-1); P = 0.53) or RPE (12.6 +/- 1 vs 12.7 +/- 1; P = 0.72). RER was significantly greater (P = 0.02) during rowing (0.99 +/- 0.07) compared with treadmill exercise (0.94 +/- 0.07).

CONCLUSION

Exercising at a specified submaximal THR during rowing versus treadmill exercise in beta-blocked men participating in very early cardiac rehabilitation represents the same VO2 and RPE. A significantly greater RER was, however, apparent during rowing compared with treadmill exercise; thus, agreement was shown with previous studies on healthy individuals where rowing ergometry was less metabolically efficient than treadmill exercise. The results suggest that establishing a THR from a standard treadmill stress test soon after MI is not only suitable for walking/treadmill exercise but also in setting exercise intensity for rowing ergometry.