Effect of ventricular function on the exercise hemodynamics of variable rate pacing

AbstractTo determine the effect of ventricular function on the exercise hemodynamics of variable rate pacing, 16 selected patients underwent paired, double-blind, randomized exercise tests in single rate demand (VVI) or variable rate (VVIR) pacing modes. Ejection fraction and cardiac index were determined by two-dimensional and Doppler echocardiography at baseline and during peak exercise.Baseline ejection fraction ranged from 14 to 73% and was < 40% in 6 patients (Group 1) and ≥ 40% in 10 patients (Group 2). Duration of exercise was longer during the VVIR mode (502 s) than during the VVI mode (449 s) (p < 0.01) and unrelated to baseline ejection fraction. Heart rate during exercise increased 9% in the VVI mode and 35% in the VVIR mode (p < 0.005). Cardiac index increased 49% in the VVI mode and 83% in the VVIR mode. Analysis of variance for repeated measures showed a significant effect of pacing mode (p < 0.01) and exercise (p < 0.001), but not baseline ejection fraction, on cardiac index. Baseline ejection fraction did not correlate with the increase in cardiac index in either pacing mode or with the difference in increase between modes. There was no significant difference between Groups 1 and 2 in exercise duration, peak heart rate-blood pressure (rate-pressure) product, baseline or peak heart rate or baseline or peak cardiac index.Therefore, in selected patients, VVIR pacing during exercise results in an increase in heart rate, duration of exercise and cardiac index that is unrelated to the degree of baseline left ventricular dysfunction. These data have clinical implications for the use of variable rate pacemakers in patients with abnormalities of ventricular function

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Patient‐reported outcomes following autologous stem cell transplant for patients with multiple myeloma

Abstract We evaluated changes in patient‐reported outcomes and cognitive function from pre‐ to 3–6 months post‐treatment among 42 newly diagnosed patients with multiple myeloma undergoing transplant with complete data using PROMIS‐29. There were statistically significant improvements in physical (p < .001) and mental health (p < .001) but not cognition from pre‐treatment to 3–6 month follow‐up. Similar results were seen within age or comorbidity strata. Patients with myeloma undergoing transplant experienced generally improved short‐term health outcomes with no significant declines in cognition

Detection of two biological markers of intercourse: prostate-specific antigen and Y-chromosomal DNA

Background Although biological markers of women\u27s exposure to semen from vaginal intercourse have been developed as surrogates for risk of infection or probability of pregnancy, data on their persistence time and clearance are limited. Study Design During 2006-2008, 52 couples were enrolled for three 14-day cycles of abstinence from vaginal sex during which women were exposed in the clinic to a specific quantity (10, 100 or 1000 μL) of their partner\u27s semen. Vaginal swabs were collected before and at 1, 6, 12, 24, 48, 72 and 144 h after exposure for testing for prostate-specific antigen (PSA) and Y-chromosome DNA (Yc DNA). Results Immediately after exposure to 1000 μL of semen, the predicted sensitivity of being PSA positive was 0.96; this decreased to 0.65, 0.44, 0.21 and 0.07 at 6, 12, 24 and 48 h, respectively. Corresponding predicted sensitivity of being Yc DNA positive was 0.72 immediately postexposure; this increased to 0.76 at 1 h postexposure and then decreased to 0.60 (at 6 h), 0.63 (at 12 h), 0.49 (at 24 h), 0.21 (at 48 h), 0.17 (at 72 h) and 0.12 (at 144 h). Conclusions Overall findings suggest that PSA may be more consistent as a marker of very recent exposure and that Yc DNA is more likely to be detected in the vagina after 12 h postexposure compared to PSA. © 2013 Elsevier Inc