A high degree of heart rate (HR) variability is found in compensated hearts with good function, whereas HR variability can be decreased with severe coronary artery disease, congestive heart failure, aging and diabetic neuropathy. To test the hypothesis that HR variability is a predictor of long-term survival after acute myocardial infarction (AMI), the Holter tapes of 808 patients who survived AMI were analyzed. Heart rate variability was defined as the standard deviation of all normal RR intervals in a 24-hour continuous electrocardiogram recording made 11 +/- 3 days after AMI. In all patients demographic, clinical and laboratory variables were measured at baseline. Mean follow-up time was 31 months. Of all Holter variables measured, HR variability had the strongest univariate correlation with mortality. The relative risk of mortality was 5.3 times higher in the group with HR variability of less than 50 ms than the group with HR variability of more than 100 ms. HR variability remained a significant predictor of mortality after adjusting for clinical, demographic, other Holter features and ejection fraction. A hypothesis to explain this finding is that decreased HR variability correlates with increased sympathetic or decreased vagal tone, which may predispose to ventricular fibrillation.

Single-site studies suggest that a 2-week program of constraint-induced movement therapy (CIMT) for patients more than 1 year after stroke who maintain some hand and wrist movement can improve upper extremity function that persists for at least 1 year. To compare the effects of a 2-week multisite program of CIMT vs usual and customary care on improvement in upper extremity function among patients who had a first stroke within the previous 3 to 9 months. The Extremity Constraint Induced Therapy Evaluation (EXCITE) trial, a prospective, single-blind, randomized, multisite clinical trial conducted at 7 US academic institutions between January 2001 and January 2003. Two hundred twenty-two individuals with predominantly ischemic stroke. Participants were assigned to receive either CIMT (n = 106; wearing a restraining mitt on the less-affected hand while engaging in repetitive task practice and behavioral shaping with the hemiplegic hand) or usual and customary care (n = 116; ranging from no treatment after concluding formal rehabilitation to pharmacologic or physiotherapeutic interventions); patients were stratified by sex, prestroke dominant side, side of stroke, and level of paretic arm function. The Wolf Motor Function Test (WMFT), a measure of laboratory time and strength-based ability and quality of movement (functional ability), and the Motor Activity Log (MAL), a measure of how well and how often 30 common daily activities are performed. From baseline to 12 months, the CIMT group showed greater improvements than the control group in both the WMFT Performance Time (decrease in mean time from 19.3 seconds to 9.3 seconds [52% reduction] vs from 24.0 seconds to 17.7 seconds [26% reduction]; between-group difference, 34% [95% confidence interval {CI}, 12%-51%]; P<.001) and in the MAL Amount of Use (on a 0-5 scale, increase from 1.21 to 2.13 vs from 1.15 to 1.65; between-group difference, 0.43 [95% CI, 0.05-0.80]; P<.001) and MAL Quality of Movement (on a 0-5 scale, increase from 1.26 to 2.23 vs 1.18 to 1.66; between-group difference, 0.48 [95% CI, 0.13-0.84]; P<.001). The CIMT group achieved a decrease of 19.5 in self-perceived hand function difficulty (Stroke Impact Scale hand domain) vs a decrease of 10.1 for the control group (between-group difference, 9.42 [95% CI, 0.27-18.57]; P=.05). Among patients who had a stroke within the previous 3 to 9 months, CIMT produced statistically significant and clinically relevant improvements in arm motor function that persisted for at least 1 year. Trial Registration clinicaltrials.gov Identifier: NCT00057018.

MILD COGNITIVE impairment (MCI) is conceptualized as a boundary or transitional state between aging and dementia.¹ Memory deficit is both the usual complaint in MCI and the cardinal feature of Alzheimer disease (AD). The major focus of MCI research has been to distinguish individuals who will progress to AD from those who will not.^1-9 Interest in MCI has been stimulated by the hope that pharmacologic intervention at this stage may delay or prevent progression to AD.¹⁰ Multicenter trials of cholinesterase inhibitor drugs and other agents with putative benefit for AD already are being conducted in individuals with MCI.

Background: Brief measures that accurately discriminate normal cognitive aging from very mild dementia are lacking. Cognitive tests often are insensitive to very mild dementia. Informant-based measures may be more sensitive in detecting early dementia.

We examined the relationships among ventricular arrhythmias, left ventricular dysfunction, and mortality after the occurrence of myocardial infarction in 766 patients who enrolled in a nine-hospital study and underwent two special tests. Frequency and repetitiveness of ventricular premature depolarizations (VPDs) were determined by computer analysis of predischarge 24 hr electrocardiographic recordings. The left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography and dichotomized at its optimal value of 30%. Frequency of VPDs was divided into three categories: (1) less than one per hour, (2) one to 2.9 per hour, and (3) three or more per hour. Repetitiveness of VPDs was also divided into three categories: (1) no repetitive VPDs, (2) paired VPDs, and (3) VPD runs. These variables were related, one at a time and jointly, to total mortality and to deaths caused by arrhythmias. The hazard ratios for dying in the higher or highest risk stratum vs the lower or lowest stratum for each variable (adjusted for the effects of the others) were: LVEF below 30%, 3.5; VPD runs, 1.9; and VPD frequency of three or more per hour, 2.0. There were no significant interactions among the three variables with respect to effects on the risk of mortality. There was a suggestion of an interaction between each risk variable and time after infarction. LVEF below 30% was a better predictor of early mortality (less than 6 months) and the presence of ventricular arrhythmias was a better predictor of late mortality (after 6 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive enlargement of cyst-filled kidneys. In a three-year study, we measured the rates of change in total kidney volume, total cyst volume, and iothalamate clearance in patients with ADPKD. Of a total of 241 patients, in 232 patients without azotemia who were 15 to 46 years old at baseline we used magnetic-resonance imaging to correlate the total kidney volume and total cyst volume with iothalamate clearance. Statistical methods included analysis of variance, Pearson correlation, and multivariate regression analysis. Total kidney volume and total cyst volume increased exponentially, a result consistent with an expansion process dependent on growth. The mean (±SD) total kidney volume was 1060±642 ml at baseline and increased by a mean of 204±246 ml (5.27±3.92 percent per year, P<0.001) over a three-year period among 214 patients. Total cyst volume increased by 218±263 ml (P<0.001) during the same period among 210 patients. The baseline total kidney volume predicted the subsequent rate of increase in volume, independently of age. A baseline total kidney volume above 1500 ml in 51 patients was associated with a declining glomerular filtration rate (by 4.33±8.07 ml per minute per year, P<0.001). Total kidney volume increased more in 135 patients with PKD1 mutations (by 245±268 ml) than in 28 patients with PKD2 mutations (by 136±100 ml, P=0.03). Kidney enlargement resulting from the expansion of cysts in patients with ADPKD is continuous and quantifiable and is associated with the decline of renal function. Higher rates of kidney enlargement are associated with a more rapid decrease in renal function.