Wear measurements with use of radiostereometric analysis in total hip arthroplasty with obscured femoral head.

Radiostereometric analysis (RSA) has evolved as gold standard in the evaluation of wear and especially as regards novel hip implant materials. However, several cup shell materials and articulation types used in total hip arthroplasty (THA) cannot be studied due to poor radiographic visibility of the femoral head (FH). We addressed this problem with use of a point transfer function in the RSA software to indirectly measure FH translations with use of stem markers. In a base examination, the stem marker segment and cup center, as an approximation for the FH center position, were mathematically coupled. Thereafter, in subsequent examinations, we used the point transfer function to calculate FH positions from stem marker positions. To determine the variance of the difference of directly and indirectly measured FH positions, four stem marker configurations were studied in THAs with radiographically visible FHs. For the axis with least variance we also compared directly and indirectly measured translation up to 7 years. Finally, we applied the method in a ceramic-on-ceramic (COC) articulation and measured proximal translation up to 7 years and also estimated precision. Vertical translations had the smallest variation between measured and calculated FH position. Directly and indirectly measured vertical FH translation correlated well but indirect measurements had increased variance. Proximal steady-state penetration rate in uncemented COC THA was -0.003 (SD 0.021) mm/year with 99% precision along the vertical axis measuring 0.34 mm. The point transfer function can be used to measure proximal FH penetration, but with less precision than direct RSA.

Limited prognostic value of noninvasive assessment of reperfusion by continuous vectorcardiography in an unselected cohort of patients with acute ST-elevation myocardial infarction treated with thrombolysis.

AIMS: We studied the prognostic value of different reperfusion criteria of short-term continuous vectorcardiography (VCG) in an unselected cohort of 400 patients with ST-elevation myocardial infarction, treated at 4 coronary care units in Stockholm, Sweden, between 1999 and 2002. The main outcome measure was 1-year mortality. RESULTS: Of 400 study patients, 41 (10.2%) died within 1 year. One-year mortality in patients without reperfusion at 90 minutes, defined as ST resolution below 50% on VCG, was 11.6% compared with 9.0% in patients with reperfusion, (P = 0.4). Ninety-eight (24.5%) patients underwent intervention before discharge and percutaneous coronary intervention or coronary artery bypass grafting or both during the index admission. Percutaneous coronary intervention or coronary artery bypass grafting was related to improved 1-year survival (97 +/- 2% vs 87 +/- 2%, P = .0076). ST-vector magnitude resolution at 90 minutes was lower in patients who underwent intervention (P = .045). None of the reperfusion criteria of VCG was significantly associated with 1-year mortality. CONCLUSION: Our results show that noninvasive assessment of reperfusion by continuous VCG has limited prognostic value in unselected patients treated with thrombolysis because of ST-elevation myocardial infarction when subsequent revascularizations are performed. However, VCG might be useful in selecting patients for coronary angiography with subsequent revascularization.

Impact of physical activity and body composition on heart function and morphology in middle-aged, abdominally obese women.

Several studies have shown training induced morphological changes in the heart. Our aim was to assess how frequent, low-intensity exercise (walking and cycling) influences heart function and morphology in abdominally obese women. Fifty women with abdominal obesity (mean age 47.0 +/- 7.5 years, waist circumference (WC) 103.2 +/- 7.8 cm), free of cardiovascular problems were recruited. They were equipped with a bicycle and pedometers and instructed to start commuting in a physically active way for 6 months. Evaluation of cardiac function and morphology was performed using echocardiography (ECHO) before and after 6 months of training. The subjects increased significantly their daily physical activity. After 6 months, there was a significant decrease in WC (from 103.3 +/- 7.9 to 100.8 +/- 8.4 cm, P = 0.0003), in systolic and diastolic blood pressure (126.8 +/- 15.2 to 120.4 +/- 14.5 mmHg, P = 0.0001, and 79.8 +/- 7.8 to 77.8 +/- 8.4 mmHg, P = 0.0006, respectively). ECHO showed an increase in the right ventricular (RV) systolic longitudinal function expressed as tricuspid annular motion from 22.00 +/- 3.30 to 23.05 +/- 3.59 mm, P = 0.015; and a similar trend in left ventricular (LV) mitral annular motion, which increased from 13.09 +/- 1.53 to 13.39 +/- 1.47 mm, P = 0.070. Cycling was associated with reductions in LV systolic and RV diastolic dimensions, whereas walking was not associated with any changes in the ECHO-variables. A reduction in WC by frequent, low-intensity exercise in abdominally obese women is associated with decrease in blood pressure and improved longitudinal RV systolic function.

Longitudinal isovolumic displacement of the left ventricular myocardium assessed by tissue velocity echocardiography in healthy individuals.

Rapid myocardial isovolumic motions are reportedly involved in the left ventricular reshaping process and may contribute to total systolic myocardial shortening. In this study, the qualitative and quantitative analysis of longitudinal myocardial isovolumic displacement was performed in 49 healthy individuals (23 men and 26 women) in age groups 21 to 49 and 50 to 76 years using tissue velocity echocardiography. The obtained isovolumic contraction and relaxation displacement curves were biphasic and displayed a significant regional heterogeneity most probably reflecting active presystolic and postsystolic reshaping of left ventricular cavity. Besides some sex difference in younger individuals, there was an age-dependent lengthening of the isovolumic relaxation time and their motion components. Even if being of short duration, the longitudinal myocardial isovolumic displacement may accounted for as much as 14% of the total longitudinal myocardial shortening, a fact which should be taken into consideration when assessing left ventricular systolic function.