Biomedical subjects

Kenneth A Mayuga

Publications and source records attributed to Kenneth A Mayuga.

3 recordsLinked to original sources

PubMed2006

Age and gender difference in ST height at rest and after double autonomic blockade in normal adults.

BACKGROUND: ST elevation is commonly seen in young, healthy men. The exact mechanisms that cause ST height to be greater in young men are not yet completely understood. The purpose of the present study was to determine whether autonomic tone is responsible for age and gender differences in ST height. METHODS: Gender and age differences in ST height were studied at rest and after double autonomic blockade (DAB) with atropine and propranolol. Fifty healthy men and women were included (16 men, 14 women, age 23-32 years; 9 men, 11 women, age 65-79 years). Twelve-lead ECGs were registered at rest and after DAB. Leads II and V(1)-V(4) were chosen for analysis. ST height (in mm) was measured manually at the J-point, and 40 ms and 80 ms after the J-point. Values were corrected for QRS amplitude. RESULTS: Gender and age differences in ST height were seen in both rest and DAB data. Men had greater ST height compared to women at J-point, 40 and 80 ms after the J-point (P < or = 0.0001), and younger subjects had greater ST height than older subjects at J-point (P = 0.0140), 40 and 80 ms after the J-point (P < or = 0.0001). DAB did not change ST height at J-point or at 40 ms, but increased ST height at 80 ms. Women had less of an increase in ST height following DAB than men did. CONCLUSIONS: ST elevation in the absence of structural or electrical heart disease is mainly seen in young men. Age and gender difference persist after DAB and thus are not due to differences in autonomic tone.

Adult↗

PubMed2006

Quality of anastomosis in conventional on-pump coronary artery bypass graft surgery: influence of the interrupted technique using u-clips and correlation with intraoperative graft flow patterns.

BACKGROUND: The interrupted suture technique in creating graft-coronary artery anastomoses in coronary artery bypass graft (CABG) surgery is hypothesized to be superior to the standard continuous technique. However, because of the increased time and knot tying involved with the interrupted technique, the continuous suture became standard. In 2000, the U-clip (a self-closing metal clip) was introduced to help in creating an interrupted anastomosis, although data regarding its clinical use are still somewhat limited. Intraop-erative transit-time flow measurement (TTFM) of blood flow through an anastomosis is frequently used to assess quality of anastomosis creation; mean flow and pulsatile index (PI) are analyzed. PI should typically be between 1 and 5; higher values are associated with errors of anastomosis creation. The current study analyzes the difference in TTFM between U-clips and standard suture in CABG surgery. METHODS: The study population consists of 30 prospectively enrolled patients undergoing first-time on-pump conventional CABG surgery at St. Anthony Medical Center who were randomized to have their anastomosis created with either U-clips or suture. TTFM were recorded for left internal mammary artery to left anterior descending artery (LIMA-LAD) anastomoses. RESULTS: Of the 30 subjects enrolled (10 women), 12 operations were done with U-clips and 18 with suture. Body mass index (BMI) in the 2 groups was similar. In terms of mean flow, there was no difference between the 2 groups (29.8 +/- 18.4 mL/min for U-clips versus 26.6 +/- 11.0 mL/min for suture, P = .57). In terms of PI, again no difference was found (3.1 +/- 1.3 for U-clips versus 2.5 +/- 0.8 for suture, P = .12). CONCLUSIONS: The findings of this study suggest that U-clips are comparable to the standard suture for LIMA-LAD anastomoses in conventional on-pump CABG surgery in terms of intraoperative assessment of graft flow.

Adult↗

PubMed2004

Menstrual cycle and ST height.

BACKGROUND: Sex hormones and menstrual cycle effects on ST height have not yet been clearly identified. METHODS: Twenty-two young, healthy women (aged 22-32 years) were included in this study. Twelve-lead ECGs were registered during menses, follicular and luteal phase of the menstrual cycle at baseline, and after double autonomic blockade (DAB). Chest leads V2-V4 and limb leads I and II were chosen for analysis. ST height was measured manually at J-Point and 40 ms after the J-Point, and values were corrected for QRS amplitude (J-Point/QRS, 40 ms/QRS). Repeated measure ANOVA was used to analyze differences in ST height among the three phases of the menstrual cycle. A P-value < 0.05 was considered as significant. RESULTS: At baseline, ST height, QTc, and T wave amplitude were not significantly different among the three phases of the menstrual cycle. After double autonomic blockade, ST height at 40 ms, J-Point/QRS, and 40 ms/QRS was significantly higher during follicular versus luteal phase (0.152 +/- 0.413 mm versus -0.007 +/- 0.427 mm, P = 0.0059 at 40 ms; -0.001 +/- 0.030 versus -0.015 +/- 0.032, P = 0.0039 at J-Point/QRS; 0.013 +/- 0.031 versus -0.004 +/- 0.032, P = 0.0005 at 40 ms/QRS) as was the QTc. ST height differences at J-Point were not significantly different (-0.046 +/- 0.395 mm follicular, -0.167 +/- 0.448 mm luteal, and -0.083 +/- 0.492 mm menses, P = 0.1014). CONCLUSION: ST height and QTc varied among the three phases of the menstrual cycle, predominantly after double autonomic blockade. Female sex hormones that vary throughout the menstrual cycle may modulate measures of repolarization.

Adult↗