Comparison of Electrocardiographic Criteria for Identifying Left Ventricular Hypertrophy in Athletes from Different Sports Modalities

OBJECTIVES: In athletes, isolated electrocardiogram high voltage criteria are widely used to evaluate left ventricular hypertrophy, but positive findings are thought to represent normal electrocardiogram alterations. However, which electrocardiogram criterion can best detect left ventricular hypertrophy in athletes of various sport modalities remains unknown. METHODS: Five electrocardiogram criteria used to detect left ventricular hypertrophy were tested in 180 male athletes grouped according to their sport modality: 67% low-static and high-dynamic components and 33% high-static and high-dynamic components of exercise. The following echocardiogram parameters are the gold standard for diagnosing left ventricular hypertrophy: left ventricular mass index ≥134 g.m-2, relative wall thickness ≥0.42 mm, left ventricular diastolic diameter index ≥32 mm.m-2, septum wall thickness ≥13 mm, and posterior wall thickness ≥13 mm. Results for the various criteria were compared using the kappa coefficient. Significance was established at p<0.05. RESULTS: Fifty athletes (28%) presented with left ventricular hypertrophy according to electrocardiogram findings, with the following sensitivities and specificities, respectively: 38-53% and 79-83% (Perugia), 22-40% and 89-91% (Cornell), 24-29% and 90% (Romhilt-Estes), 68-87% and 20-23% (Sokolow-Lyon), and 0% and 99% (Gubner). The Perugia and Cornell criteria had higher negative predictive values for the low-static and high-dynamic subgroup. Kappa coefficients were higher for Romhilt-Estes, Cornell and Perugia criteria than for Sokolow-Lyon and Gubner criteria. CONCLUSION: All five evaluated criteria are inadequate for detecting left ventricular hypertrophy, but the Perugia, Cornell and Romhilt-Estes criteria are useful for excluding its presence. The Perugia and Cornell criteria were more effective at excluding left ventricular hypertrophy in athletes involved in a sport modality with low-static and high-dynamic component predominance.

Choroidal thickness changes after dynamic exercise as measured by spectral‑domain optical coherence tomography.

Purpose: To measure the choroidal thickness (CT) after dynamic exercise by using enhanced depth imaging optical coherence tomography (EDI‑OCT). Materials and Methods: A total of 19 healthy participants performed 10 min of low‑impact, moderate‑intensity exercise (i.e., riding a bicycle ergometer) and were examined with EDI‑OCT. Each participant was scanned before exercise and afterward at 5 min and 15 min. CT measurement was taken at the fovea and 1000 μ away from the fovea in the nasal, temporal, superior, and inferior regions. Retinal thickness, intraocular pressure, ocular perfusion pressure (OPP), heart rate, and mean blood pressure (mBP) were also measured. Results: A significant increase occurred in OPP and mBP at 5 min and 15 min following exercise (P ˂ 0.05). The mean subfoveal CT at baseline was 344.00 ± 64.71 μm compared to 370.63 ± 66.87 μm at 5 min and 345.31 ± 63.58 μm at 15 min after exercise. CT measurements at all locations significantly increased at 5 min following exercise compared to the baseline (P ˂ 0.001), while measurements at 15 min following exercise did not significant differ compared to the baseline (P ˃ 0.05). There was no significant difference in retinal thickness at any location before and at 5 min and 15 min following exercise (P ˃ 0.05). Conclusion: Findings revealed that dynamic exercise causes a significant increase in CT for at least 5 min following exercise.

Muscarinic antibodies and heart rate responses to dynamic exercise and to the Valsalva maneuver in chronic chagasic patients / Anticorpos muscarínicos e resposta da frequência cardíaca ao exercício dinâmico e a manobra de Valsalva na doença de Chagas crônica

We have studied the cardiac chronotropic responses to the Valsalva maneuver and to dynamic exercise of twenty chronic chagasic patients with normal left ventricular function and no segmental wall abnormalities by two-dimensional echocardiogram. The absolute increase in heart rate of the patients (Δ = 21.5 ± 10 bpm, M±SD) during the maneuver was significantly diminished when compared to controls (Δ = 31.30 ± 70, M±SD, p = 0.03). The minimum heart rate (58.24 ± 8.90 vs. 62.80 ± 10, p = 0.68) and the absolute decrease in heart rate at the end of the maneuver (Δ = 38.30 ± 13 vs. Δ = 31.47 ± 17, p = 0.10) were not different from controls. The initial heart rate acceleration during dynamic exercise (Δ = 12 ± 7.55 vs. Δ = 19 ± 7.27, M±SD, p = 0.01) was also diminished, but the heart rate recovery during the first ten seconds was more prominent in the sero-positive patients (Median: 14, Interquartile range: (9.75-17.50 vs. 5(0-8.75, p = 0.001). The serum levels of muscarinic cardiac auto-antibodies were significantly higher in the chagasic patients (Median: 34.58, Interquartile Range: 17-46.5, Optical Density) than in controls (Median: 0, Interquartile Range: 0-22.25, p = 0.001) and correlated significantly and directly (r = 0.68, p = 0.002) with early heart rate recovery during dynamic exercise. The results of this investigation indirectly suggest that, the cardiac muscarinic auto-antibodies may have positive agonist effects on parasympathetic heart rate control of chagasic patients.

Foram estudadas as respostas cronotrópicas cardíacas à manobra de Valsalva e ao exercício dinâmico de vinte pacientes chagásicos com função ventricular esquerda normal e sem alterações da contractilidade segmentar por ecocardiografia bidimensional. O aumento absoluto da frequência cardíaca dos pacientes (Δ = 21,5 ± 10 bpm, M ± DP) durante a manobra de Valsalva foi significativamente menor quando se comparava ao grupo controle (Δ = 31,30 ± 70, p = 0,03). A frequência cardíaca mínima (58,24 ± 8,90 vs 62,80 ± 10, p = 0,68) e a diminuição da frequência cardíaca absoluta no final da manobra (Δ = 38,30 ± 13 vs Δ = 31,47 ± 17, p = 0,10) não foram diferentes em comparação com o grupo controle. A aceleração inicial da frequência cardíaca durante o exercício dinâmico (Δ = 12 ± 7,55 vs Δ = 19 ± 7,27, p = 0,01) também foi menor, mas a recuperação da frequência cardíaca, durante os primeiros dez segundos, foi maior no grupo sero-positivos [mediana:14 (intervalo interquartil: 9,75-17,50) vs 5 (0 - 8,75), p = 0,001]. Os níveis séricos de auto-anticorpos muscarínicos cardíacos foram significativamente maiores nos pacientes chagásicos do que no grupo controle [(mediana: 34,58 densidade óptica (intervalo interquartil 17 - 46,5) vs (mediana: 0, intervalo interquartil 0 - 22,25) p = 0,001] e a correlação é significativa e direta (r = 0,68, p = 0,002) com o início da recuperação da frequência cardíaca durante o exercício dinâmico. Os resultados desta investigação sugerem que indiretamente, os auto-anticorpos muscarínicos cardíacos, podem ter ação agonista positiva sobre o controle parassimpático da frequência cardíaca dos pacientes chagásicos.

Effects of Ovarian Cycle on Hemodynamic Responses during Dynamic Exercise in Sedentary Women

This study tested the hypothesis that effects of the menstrual cycle on resting blood pressure carry over to dynamic exercise. Eleven healthy females were studied during the early (EP; low estrogen, low progesterone) and late follicular (LP; high estrogen, low progesterone) menstrual phases. Stroke volume (SV), heart rate (HR), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), and total vascular conductance (TVC) were assessed at rest and in response to mild and moderate cycling exercise during EP and LP. During EP, compared to LP, baseline SBP (111+/-1 vs. 103+/-2 mmHg), DBP (71+/-2 vs. 65+/-2 mmHg) and mean arterial pressure (MAP) (84+/-2 vs. 78+/-1 mmHg) were higher and TVC (47.0+/-1.5 vs. 54.9+/-4.2 ml/min/mmHg) was lower (p<0.05). During exercise, absolute values of SBP (Mild: 142+/-4 vs. 127+/-5 mmHg; Moderate: 157+/-4 vs. 144+/-5 mmHg) and MAP (Mild: 100+/-3 vs. 91+/-3 mmHg; Moderate: 110+/-3 vs. 101+/-3 mmHg) were also higher, while TVC was lower (Mild: 90.9+/-5.1 vs. 105.4+/-5.2 ml/min/mmHg; Moderate: 105.4+/-5.3 vs. 123.9+/-8.1 ml/min/mmHg) during EP (p<0.05). However, exercise-induced increases in SBP, MAP and TVC at both work intensities were similar between the two menstrual phases, even though norepinephrine concentrations were higher during LP. Results indicate that blood pressure during dynamic exercise fluctuates during the menstrual cycle. It is higher during EP than LP and appears to be due to additive effects of simultaneous increases in baseline blood pressure and reductions in baseline TVC.

The diagnosis of coronary insufficiency by the combined dynamic-postexercise electrocardiographic test

Analysis of the results of the Dynamic Exercise and Post-Exercise ECG tests given to 206 young normal subjects and to 302 patients with probable, presumptive, or definite evidence of coronary heart diseases revealed the following1. Using ischemic ST depression of at least 1.0 mm as the sole criterion for a positive test, the Dynamic Exercise ECG did not give more "false positive" results than the Post-Erxercise ECG in the known normal subjects while in the "coronary" patients, the Dynamic Exercise ECG detected almost five times as many coronary insufficiencies as the Post-Exercise ECG2. Junctional ST depressions of 1.5 mm or more in the Post-Exercise ECG were found to be residuals of previous ischemic ST depressions in about 60 per cent of cases, and should therefore be regarded as suspicious indications of coronary insufficiency whenever the Dynamic Exercise ECG is unavailable3. The significance of and the possibility of the inclusion of "prolonged" QTc interval as a criterion to increase the sensiitivity of the Exercise Test was discussed4. Despite the demonstrated superiority of the Dynamic Eercise ECG it had a few limitations which the post exercise ECG could compensate. In view of this, it was recommended that the two exercise ECG tests be combined for which the name "Combined Dynamic-Post-exercise ECG Test" was proposed."(Summary and Conclusions)

Quantitative Analysis of Isotonic Exercise Using Virtual Reality Motion Analysis System(VRMAS)

Isotonic exercise occurs when the tension or torque generated by a muscle is constant throughout the movement. In practice it is very difficult to maintain the tension constant. Evaluation of isotonic exercise should include the works of concentric and eccentric contraction and the changes in tension and torque during joint motion. However, optimal evaluation tools for isotonic exercise has yet to be developed. We authors, used virtual reality motion analysis system(VRMAS) which was codeveloped by us and EMG system(Cardwell Excel). Healthy male adult subjects(n=10) were recruited from hospital personnel. After dominant upper arm and trunk of each subject was fixed with velcro, he was instructed to repeat flexion and extension of his dominant elbow grasping dumbell (9 kg) in hand with maximal velocity as possible as can until the point of exhaustion. We measured the elbow angle, the angular velocity, torque, power, total work and the work of concentric and eccentric contraction during exercise. The results were as follows: there were four distinct elbow flexor muscle contractions during flexion and extension of the elbow with the first and the second contractions during concentric contraction and the third and the fourth contractions during eccentric contraction. Between the peaks of contraction, motion was maintained due to the momentum that was generated. Of the ten subjects, seven had higher concentric work than eccentric work with the eccentric work being higher in the remaining three. But there was no statistic significance between the works of concentric contraction and eccentric contraction(p>0.05). The biggest work was observed in the fourth contraction, while the third contraction showed the least work(p<.05). In conclusion, there were four distinct muscle contractions during elbow isotonic exercise and the works of each muscle contraction were different. This result is contrary to the definition of isotonic exercise. This study also shows that the VRMAS could be a very useful evaluation tool for several types of isotonic exercise.

Change in plasma adenosine concentration during and after dynamic exercise in healthy men / 体力科学

To evaluate the contribution of adenosine (AD) to exercise capacity, plasma concentrations of AD were assessed before, during and after dynamic exercise in 6 healthy men (24-32yr) . The exercise protocol was a symptom-limited ramp exercise test. Blood pressure, heart rate and respiratory gas exchange parameters were monitored throughout the exercise test. The first exercise test (EX 1) was performed to determine the anaerobic threshold (AT) . The second exercise test (EX 2) was performed 2 days after EX 1 and blood samples for assay of AD, lactate and norepinephrine (NE) were taken from the cubital vein at rest, before and after AT, at peak exercise, and 5, 10, 15min after EX 2. Blood for assay of AD was collected into a vaccum tube with EDTA, dipyridamole and 2'-deoxycoformycin. Plasma AD concentrations were measured by the RIA.<BR>The mean AD concentration±S. D. at rest, before and after AT, at peak exercise, 5, 10 and 15min after exercise was 22±11.8pmol/m<I>l</I>, 45±20.7, 63±33.6, 123±82.1, 186±146.9, 154±127.7 and 150±68.5, respectively. A significant increase of AD concentration was observed during the period from before AT until 15 min after exercise, as compared with that at rest. There was a significant relation between AD and lactate (r=0, 54, p<0.01), but there was no significant relation between AD and NE (r=0.08) .<BR>It is concluded that AD may be a contributing factor to increase exercise capacity through its vasodilation effect, suggesting a paracrine interaction between the exercising skeletal muscle and blood vessels.

Thermographic observations of the skin related with the arm exercise / 体力科学

To visualize skin temperatures during the dynamic and static arm exercises, a monochromatic thermograph was used.<BR>The thermoviewer JTG system presented a 5-monochromatic step-thermal display in centaral temperatures of 34.5 or 34.0°C and a temperature range of 2°C. The temperature resolving power of the system was 0.2°C. A 35 mm camera was used to take a synchronous thermogram of 2 sec scanning time.<BR>The experiments were carried out in August in an experimental room with an air temperature of 27.3±0.6°C, and a relative humidity of 50.5±4.3%.<BR>The skin temperatures of the forearm, upper arm and chest for five male subjects (18-25 yr) were observed before, during and after 5 min exercise on an arm ergometer at work intensities of 0, 2, 3 and 4 kg (dynamic exercise : a rate of 40 contractions/min as timed with a metoronome) .<BR>The following results were obtained.<BR>1) Changes in skin temperatures were observed in detail and over a wide area during the dynamic and static exercises.<BR>2) The upper arm skin temperature increased as soon as that of the shoulder fell immediately after the beginning of dynamic exercise.<BR>3) The decrease in skin temperatures on the chest, shoulder and upper arm appeared with static exercise.<BR>4) The fall in skin temperature increased and spread from forearm toward chest with the incresse in static work intensity.

EFFECTS OF STATIC EXERCISE AND DYNAMIC EXERCISE ON SYSTOLIC TIME INTERVALS (STI) IN CHILDREN / 中国运动医学杂志

The purpose of this study was to investigate STI changes resulting from static and dynamic exercises in boys, 9-10 years old, so as to reveal the effects of physical work of different types and loads on the heart function.Our research showed that the effects of static load and dynamic load on STI in children were different. After dynamic exercise all items of STI changed significantly and PEP/LVET decreased significantly. No PEP change was found after static exercises (50% and 80% max load). Static exercise of 50% max load resulted in no IVCT change, but static exercise of 80% max load resulted in very significant change of IVCT, and the longest recovery period was found afterwards. Thus, 80% static exercise would result in a heavy, transient heart load in children.Our research also showed that the changes of HR?systolic blood pressure?LVET after dynamic load and static load were significantly different indicating that oxygen consumption in heart muscles was higher during dynamic exercise and the effect of dynamic exercise on heart was stronger.