A GUIDE FOR THE CO-ORDINATION IN THE FRONT CRAWL VARIANTS

In this presentation an interactive cd-rom, describing and discussing the front crawl of high level swimmers, is introduced; more specifically several variants (e.g. 6-beat, 2-beat, 2 beat crossover) and different technique aspects. The intention is that the coach corrects the own competition swimmers and triathletes, based on a careful video observation. Therefore, only practical knowledge is collected, confirmed by expertise and applied research at the K.U.Leuven Evaluation Centre. Different variants and technique aspects are clarified by video images of recent swimmers at national level in different speeds, obtained with 5 rotating cameras from 5 points of view. To be able to start with an Evaluation Centre, in the movement analysis of high level swimmers special attention was given to the co-ordination of the arm, leg and head movements (relative to the body) and of the body movements (relative to the water surface). Since the Olympic Games in Munich (1972), for each segment clearly delimited phases were studied in the stroke cycle of each variant. An interesting criterion for propulsion is the speed variation of the body from phase to phase. Each swimmer can feel propulsion per phase, estimated by the coach on video, from bubbles displaced backward; each swimmer can also feel the coordination, observable by the coach on video. Although the optimal variant per distance of a swimmer could be determined from his physical profile (e.g.; body structure, buoyancy, flexibility, strength,,,), each individual is advised to experiment with the different variants and technique aspects. Speed and/or economy remain the essential criterions. The body control of swimmers must thus be very adaptable

Assessment of Coronary Flow Reserve During Angioplasty Using A Doppler Tip Balloon Catheter. Comparison With Digital Subtraction Cineangiography

Intracoronary blood flow velocity measurements with a Doppler probe and the radiographic assessment of myocardial perfusion with contrast media previously have been used to investigate regional coronary flow reserve. In the present study we applied both techniques in the same patients to measure the immediate improvement in coronary flow reserve as a result of angioplasty. In addition we compared papaverine induced hyperemia with reactive hyperemia following transient transluminal occlusion of a major coronary artery. In 13 consecutive patients with a single proximal stenosis, coronary flow reserve was measured pre‐ and postangioplasty by digital subtraction cineangiography, while pre‐ and postangioplasty Doppler measurements before and after papaverine were obtained in the proximal part of the stenotic vessel. After the last transluminal occlusion, reactive hyperemia recorded with the Doppler probe was also compared to the coronary flow reserve measurement obtained during papaverine induced hyperemia. As a result of the angioplasty, coronary flow reserve measured with the radiographic technique (mean ± SD) increased from 1.1 ± 0.4 to 2.2 ± 0.4 (P < 0.001), while coronary flow reserve measured with the Doppler probe (mean ± SD) increased from 1.2 ± 0.3 to 2.4 ± 0.4 (P < 0.001). Pharmacologically induced hyperemia measured with the radiographic technique and the Doppler probe were linearly related (r = 0.91 with a SEE 0.3) and confirmed the reliability of the intracoronary measurements. Using these two independent techniques, coronary flow reserve immediately after angioplasty was found to be substantially improved but still abnormal. In addition, the magnitude of hyperemia induced by papaverine was comparable to the reactive hyperemia following transluminal occlusion, although the latter measurement was recorded with the angioplasty catheter still across the dilated lesion. (J Interven Cardiol, 1988:1:1) Copyrigh

Curved track sprint characteristics in elementary school children

The management strategies of patients who underwent Mustard repair for transposition (of the great arteries were changed in the 1970s: infants became eligible for direct surgical repair, so Blalock-Hanlon atrioseptostomy could be avoided, and cold cardioplegia was introduced for myocardial preservation. Data are lacking, however, regarding whether these changes have had positive effects on the long-term outcome. We therefore conducted a follow-up study on all 91 patients who underwent a Mustard repair for transposition of the great arteries in our institution between 1973 and 1980 to assess the incidence and clinical importance of sequelae as well as health-related quality of life for these patients. Patients who were alive and could be traced through local registrar's offices received an invitation to participate in the follow-up study, which consisted of an interview, physical examination, echocardiography, exercise testing, and standard 12-lead and 24-hour electrocardiography. Patients operated on in the first 4 years had a significantly higher mortality rate and higher incidence of sinus node dysfunction than did patients operated on in the subsequent 4 years (25% vs 2% and 41% vs 3%, respectively). In contrast, the incidence of baffle obstruction necessitating reoperation was significantly higher in the second group. There were no significant differences in echocardiographic findings and exercise capacity between patients operated on in the first 4 years and in the subsequent 4 years. None of the patients had right ventricular failure; a mild degree of baffle leakage or obstruction was seen in 22% of the patients, and the mean exercise capacity was decreased to 84% +/- 16% of normal. The changes introduced between 1973 and 1980 have resulted in a considerable reduction of mortality and incidence of sinus node dysfunction but have also resulted in a more frequent need for reoperatio

The relative contributions of myocardial wall thickness and ischemia to ultrasonic myocardial integrated backscatter during experimental ischemia

Abstract The purpose of this study was to assess the empirical relationship between myocardial integrated backscatter (IB) and myocardial wall thickness (WT) in normal myocardium. A second object was to estimate the additional contribution to acute ischemic integrated backscatter levels given this relationship. Myocardial IB measurements and simultaneous myocardial WT measurements were made in 16 open-chested pigs with intact coronary circulation (normal myocardium) and 10 min after the flow in the left anterior descending coronary artery had been reduced to 20% of its baseline value (ischemic myocardium). Measurements were made 50 times during one cardiac cycle and averaged over 10 cardiac cycles. IB and WT measurements were normalized with respect to the nonischemic end-diastolic values. The relationship between IB and WT in normal myocardium was estimated in every individual pig by simple linear regression. Estimates of IB during ischemia were calculated on the basis of this relationship and the ischemic WT measurements. Differences of the estimator and the actual measurement made during ischemia depict the actual contribution of the state of acute ischemia, without the influence of WT. The slope of the relationship between IB and WT during normal myocardial contraction ranged from −0.16 to 0.03 dB/% (mean = −0.036 dB/%, SD = 0.06 dB/%). The additional contribution of ischemia ranged from −3.84 to 5.56 dB (mean = 0.31 dB, SD = 2.72 dB). It was concluded that the average contribution of ischemia to IB measurements is insignificant if the IB dependency on WT is removed from the data and that the higher level of ischemic IB measurements can be explained by the decrease in wall thickness during ischemia and not by the ischemia itself

Prevalence of myocardial viability assessed by single photon emission computed tomography in patients with chronic ischaemic left ventricular dysfunction

OBJECTIVE: To assess the prevalence of myocardial viability by technetium-99m (Tc-99m)-tetrofosmin/fluorine-18-fluorodeoxyglucose (FDG) single photon emission computed tomography (SPECT) in patients with ischaemic cardiomyopathy. DESIGN: A retrospective observational study. SETTING: Thoraxcenter Rotterdam (a tertiary referral centre). PATIENTS: 104 patients with chronic coronary artery disease and severely depressed left ventricular function presenting with heart failure symptoms. MAIN OUTCOME MEASURES: Prevalence of myocardial viability as evaluated by Tc-99m-tetrofosmin/FDG SPECT imaging. Two strategies for assessing viability in dysfunctional myocardium were used: perfusion imaging alone, and the combination of perfusion and metabolic imaging. RESULTS: On perfusion imaging alone, 56 patients (54%) had a significant amount of viable myocardium, whereas 48 patients (46%) did not. Among the 48 patients with no significant viability by perfusion imaging alone, seven additional patients (15%) had significantly viable myocardium on combined perfusion and metabolic imaging. Thus with a combination of perfusion and metabolic imaging, 63 patients (61%) had viable myocardium and 41 (39%) did not. CONCLUSIONS: On the basis of the presence of viable dysfunctional myocardium, 61% of patients with chronic coronary artery disease and depressed left ventricular ejection fraction presenting with heart failure symptoms may be considered for coronary revascularisation. The combination of perfusion and metabolic imaging identified more patients with significant viability than myocardial perfusion imaging alone

Coronary blood flow velocity during percutaneous transluminal coronary angioplasty as a guide for assessment of the functional result

To investigate the clinical usefulness of intracoronary Doppler recordings during percutaneous transluminal coronary angioplasty (PTCA), the changes of intracoronary blood flow velocity during PTCA were assessed in 20 patients with single proximal coronary stenosis, using a Doppler probe end-mounted on the tip of a PTCA catheter. A mean of 4 inflations was performed in each patient. Intracoronary velocities were measured before and after each inflation and during peak reactive hyperemia after each transluminal occlusion. Quantitative analysis of the coronary stenosis was assessed before and after PTCA, and the dilatation resulted in an increase in minimal luminal cross-sectional area from 1.1 +/- 0.8 to 2.7 +/- 1.2 mm2. A gradual and significant improvement in velocities was obser

The relationship between myocardial integrated backscatter, perfusion pressure and wall thickness during isovolumic contraction: An isolated pig heart study

The independent effect of myocardial wall thickness and myocardial perfusion pressure on integrated backscatter was investigated through experiments wherein integrated backscatter of normally perfused myocardial tissue was measured while changes in wall thickness during the cardiac cycle were reduced to a minimum. Results of the experiments show that integrated backscatter is mainly determined by myocardial wall thickness if only wall thickness and perfusion pressure are involved

Prognostic value of dobutamine-atropine stress myocardial perfusion imaging in patients with diabetes

OBJECTIVE: Exercise tolerance in patients with diabetes is frequently impaired due to noncardiac disease such as claudication and polyneuropathy. This study assesses the prognostic value of dobutamine stress myocardial perfusion imaging in patients with diabetes. RESEARCH DESIGN AND METHODS: A total of 207 consecutive diabetic patients who were unable to undergo exercise stress testing underwent dobutamine-atropine stress myocardial perfusion imaging. Follow-up was successful in 206 of 207 (99.5%) patients. A total of 12 patients underwent early (<60 days) revascularization and were excluded from the analysis. End points during follow-up were hard cardiac events, defined as cardiac death and nonfatal myocardial infarction. RESULTS: Abnormal myocardial perfusion was detected in 125 (64%) patients. During 4.1 +/- 2.4 years of follow-up, 73 (38%) deaths occurred, 36 (49%) of which were due to cardiac causes. Nonfatal myocardial infarction occurred in 7 (4%) patients, and 45 (23%) patients underwent late coronary revascularization. Cardiac death occurred in 2 of 69 (3%) patients with normal myocardial perfusion and in 34 of 125 (27%) patients with perfusion abnormalities (P < 0.0001). A multivariable Cox proportional hazard model demonstrated that, in addition to clinical and stress test data, an abnormal scan had an incremental prognostic value for prediction of cardiac death (hazard ratio 7.2, 95% CI 1.7-30). The summed stress score was an important predictor of cardiac death; the hazard ratio was 1.2 (95% CI 1.07-1.34) per one-unit increment. CONCLUSIONS: Dobutamine-atropine stress myocardial perfusion imaging provides additional prognostic information incremental to clinical data in patients with diabetes who are unable to undergo exercise stress testing

Dobutamine-atropine stress echocardiography and clinical data for predicting late cardiac events in patients with suspected coronary artery disease

purpose: To compare the relative value of clinical variables with dobutamine-atropine stress echocardiography to predict cardiac events during long-term follow-up. Dobutamine stress echocardiography is increasingly used for the detection of coronary artery disease, but little is known of its prognostic value. patients and methods: A total of 430 patients (310 men; mean age 61 years, range 22 to 90) were enrolled in the study. Patients were referred for chest pain complaints and were unable to perform an adequate exercise stress test. All patients underwent dobutamine-atropine stress test (incremental dobutamine infusion: 10 to 40 μ/kg/minute, continued with atropine 0.25 to 1 mg intravenously if necessary to achieve 85% of the age predicted maximal heart rate, without symptoms or signs of ischemia) and clinical cardiac evaluation. Follow-up was 17 ± 5 months, with a minimum of 6 months; 3 patients were lost to follow-up. Cardiac events were defined as cardiac death, nonfatal myocardial infarc