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Biomedical subjects

F Atienza

Publications and source records attributed to F Atienza.

7 recordsLinked to original sources
PubMed2003

The relationship between professional tournament structure on the national level and success in men's professional tennis.

This article discusses the relationship between a nation's men's professional tennis tournament structure and that nation's success in the international men's game. The 2002 men's professional tennis tournament calendar provided the distribution of events on the top thirty nations. Criteria for a nation's success in men's professional tennis were: nation's number of players with ATP points, nation's number of players in the top 200 ranking, and the combined ATP ranking of a nation's top 5 male players. Pearson correlations were performed between the number of tournaments and each criterion. Results showed a considerable variation in the number of events ranging between 67 (United States) and 4 (Sweden). On the other hand, 29 of the 30 countries had Internationally ranked male player/s and 22 had player/s ranked inside the top 200. Results also showed that: 1. nations with a high number of men's professional events are best positioned to provide for more professionally ranked players, 2. nations with more professional men's tournaments are likely to experience success in the men's international game, and 3. having a high number of tournaments is not a prerequisite to having a group of players ranked among the game's elite. It can be concluded that competition is an important factor in player development and that countries who want to be successful at the professional level should try to provide best competitive progression for their players.

Humans↗
PubMed2000

Risk stratification in heart failure using artificial neural networks.

Accurate risk stratification of heart failure patients is critical to improve management and outcomes. Heart failure is a complex multisystem disease in which several predictors are categorical. Neural network models have successfully been applied to several medical classification problems. Using a simple neural network, we assessed one-year prognosis in 132 patients, consecutively admitted with heart failure, by classifying them in 3 groups: death, readmission and one-year event-free survival. Given the small number of cases, the neural network model was trained using a resampling method. We identified relevant predictors using the Automatic Relevance Determination (ARD) method, and estimated their mean effect on the 3 different outcomes. Only 9 individuals were misclassified. Neural networks have the potential to be a useful tool for making prognosis in the domain of heart failure.

Disease-Free Survival↗
PubMed1999

Assessment of quality of life in patients with chest pain and normal coronary arteriogram (syndrome X) using a specific questionnaire.

BACKGROUND: Prognosis in patients with syndrome X (chest pain and normal coronary arteriograms) is good; however, persistent chest pain and functional disability are common in these patients. Accurate assessment of quality of life may be useful for patient management. AIM: The quality of life status in patients with syndrome X was assessed using a specific questionnaire. This questionnaire was developed and validated for the assessment of quality of life in patients with typical chest pain despite normal coronary arteriograms. METHODS: Ninety consecutive patients were invited to complete both the questionnaire (on two occasions within 2 weeks) and a standardized angina dairy. Fully completed questionnaires were received from 66 (73%) patients (mean age 58 +/- 8 years, 55 women). RESULTS: Answers were scored according to a grading system where higher scores indicate worse quality of life. We observed that total scores increased with severity of angina (Canadian Class I, 38 +/- 16, II: 93 +/- 29, III-IV, 119 +/- 23; p < 0.001) and correlated with both the number and the severity of chest pain episodes (r = 0.50-0.66: p < 0.001). In patients who remained clinically stable (n = 37) during the 2-week assessment, test-retest analysis showed no score differences (87 +/- 30 vs. 81 +/- 30; p = 0.1), while total score increased in patients (n = 24) whose symptoms worsened (108 +/- 31 vs. 116 +/- 31; p < 0.02) and was reduced in those (n = 5) whose symptoms improved (55 +/- 37 vs. 39 +/- 28; p < 0.04). CONCLUSION: Our study shows that quality of life is significantly impaired in patients with syndrome X and that the specific questionnaire used for assessment is a reliable and sensitive tool for the evaluation of quality of life in patients with chest pain and normal coronary arteriograms.

Aged↗
PubMed1998

Angiographic progression in patients with angina pectoris and normal or near normal coronary angiograms who are restudied due to unstable symptoms.

BACKGROUND: Syndrome X patients commonly remain symptomatic during follow-up and may be readmitted with unstable anginal symptoms. Angiographic disease progression must be considered as a possible mechanism for instability, particularly where multiple coronary risk factors are present and an interval of several years has elapsed since previous angiography. METHODS AND RESULTS: We reviewed data from 139 consecutive patients with chest pain and normal or near normal coronary angiograms (101 patients with completely normal angiograms and 38 patients with minimal lumenal irregularities). During a 5-year period, 24 patients (19 women, median age 56 years) underwent repeat angiography due to primary unstable angina (median interval between angiograms 58 months (range 8-130 months)). This group included three patients with minimal lumenal irregularities and four patients with left bundle branch block. Only two patients had progression to significant angiographic stenosis (> 30% diameter reduction); both were male patients with minimal irregularities at baseline angiography, left bundle branch block and multiple coronary risk factors. However, overall only two of 18 (11%) patients with one or more conventional coronary risk factors had angiographic progression. CONCLUSIONS: Unstable symptoms in patients with chest pain and previously normal or near normal coronary arteriograms are rarely due to angiographic disease progression. However, the presence of minimal lumenal irregularities at baseline angiography and LBBB may identify a sub-group at increased risk.

Adult↗
PubMed1996

Recovery curve and concealed conduction in the His-Purkinje system of the rabbit heart: effects of radiofrequency modification of the low AV junction.

UNLABELLED: The aim of this study was to analyze the recovery curve and concealed conduction in the normal His-Purkinje system and after delivering radiofrequency current in the low AV junction, in the perfused rabbit heart. Twenty-one rabbit hearts were studied. Radiofrequency current (5 W) was delivered in the low AV junction to induce an incomplete His-Purkinje AV block (HV prolongation with 1:1 AV conduction); this was achieved in 9 experiments (Group I), while 12 experiments developed a complete block (Group II). Atrial stimulation was performed in both Groups at baseline, and in Group I after radiofrequency delivery, as follows: (1) pacing at increasing rates to determine the His-Purkinje AV block cycle length; (2) atrial extrastimulus test (A1A2) to calculate the His-Purkinje effective refractory period and the fitting of the recovery curve (H1H2 vs H2V2) to the exponential equation delta HV = a.e(-b)x(H1H2); (3) concealed conduction protocol (in 15 experiments) consisting of an atrial extrastimulus test with an interposed beat (A1-A0-A2) at a fixed A1A0 coupling interval. The baseline recovery curve fitted an exponential equation in 17 experiments (with a 93% +/- 42% maximum H2V2 increase at the shortest H1H2), but did not in 4 experiments (the maximum H2V2 increase being only 22% +/- 7%). Radiofrequency application prolonged the HV interval (25 +/- 6 ms vs 46 +/- 16 ms; P = 0.001) and His-Purkinje effective refractory period (167 +/- 28 ms vs 217 +/- 57 ms; P = 0.02). The percentage increment was greater for HV than for refractory period (99% +/- 65% vs 35% +/- 32%; P = 0.02); however, the increment of the His-Purkinje block cycle length (77% +/- 74%) only correlated with that of the refractory period (r = 0.95; P = 0.0001). The recovery curve after radiofrequency delivery fitted an exponential equation in all experiments, showing a rightward shift expressed by an increment of the constant ln a (2.7 +/- 1.9 vs 5.5 +/- 5.5; P = 0.02). Concealed conduction appeared in only three experiments at baseline. After radiofrequency, however, it was observed in all experiments, producing a rightward shift of the recovery curve and an ln a increase (2.87 +/- 1.2 vs 9.9 +/- 2.7; P = 0.0001). When Ho was conducted, the curve rightward shift and ln a increase (26 +/- 7.5; P = 0.0001) were greater. CONCLUSION: (1) His-Purkinje physiology, as in AV nodal physiology, can be described by a recovery curve that fits an exponential equation, especially if conduction becomes depressed with radiofrequency current. (2) Radiofrequency application in the low AV junction modifies His-Purkinje conduction more than refractoriness, though the refractoriness increase determines the degree of block at fast atrial rates. (3) Concealed conduction is uncommon in the normal His-Purkinje system during atrial pacing, but very frequent after modifying the low AV junction with radiofrequency current.

Animals↗
PubMed1994

Factor analysis and reliability of the Movement Imagery Questionnaire.

The purpose of this work was to analyze the factor structure, estimate reliability of the Movement Imagery Questionnaire of Hall and Pongrac, and examine differences between men and women on factor scores. The results for 63 men and 47 women supported the bifactorial structure and reliability of this self-report and its adequacy in comparisons of visual and kinesthetic imagery scores.

Adolescent↗