ABSTRACT
Left ventricle to right atrial communication is a rare cardiac pathology, and it is either congenital or acquired. Recently, case reports of acquired left ventricle to right atrial communication have been increasing because of the increased numbers of cardiovascular procedures and improved cardiac diagnostic techniques. We report a case of acquired left ventricle to right atrial communication in a patient with native aortic valve infective endocarditis. A 52-year-old man with worsening dyspnea on exertion and lower leg edema was admitted to a hospital. Blood examination revealed elevated inflammatory marker levels, and transthoracic echocardiography (TTE) showed an aortic valve vegetation. The patient was subsequently transferred to our hospital for infective endocarditis with congestive heart failure. Medical treatment with antibiotics and diuretics was initiated. Cardiac computed tomography (CT) demonstrated left ventricle to right atrial communication. An urgent operation was performed wherein the defect was closed with autologous pericardial patches from both the right atrium and left ventricle. Aortic valve replacement was performed with a mechanical valve. The postoperative course was uneventful, and TTE showed no residual shunt. In our case, cardiac CT was useful for accurately diagnosing left ventricle to right atrial communication.
ABSTRACT
A 67-year-old man with dyspnea at rest was diagnosed with acute heart failure and admitted to our hospital. Echocardiogram showed severe AR, and CT implied an ascending aortic aneurysm and abnormal space in the aortic root. The patient underwent emergent surgery for suspected acute aortic dissection. Intraoperative findings showed the dehiscence of commissure of the aortic valve, and more, the abnormal space in the aortic root was not due to acute aortic dissection but an aortic subannular left ventricular aneurysm. The aneurysm was sutured and closed, and after that, aortic valve replacement and ascending aortic replacement were performed. Although subannular left ventricular aneurysm is a rare disease, it is important to carry out the preoperative evaluation considering the existence of such diseases.
ABSTRACT
A 77-year-old woman was admitted to our hospital with a decreased level of consciousness and left hemiplegia. Contrast-enhanced CT showed acute type A aortic dissection and right common carotid artery occlusion. Electrocardiogram findings showed ST segment elevation in the anterolateral wall. The results suggested that the aortic dissection had extended to the left main trunk and caused acute myocardial infarction. Percutaneous coronary intervention (PCI) was performed preoperatively to improve myocardial ischemia reperfusion. After a successful PCI, the patient underwent ascending aorta replacement immediately. In cases of acute aortic dissection involving the left main artery, preoperative PCI prevents extensive myocardial damage and serves as a bridge to surgery.
ABSTRACT
In the context of energetics related to a pendular model, the mechanical power (<I>W</I>) and ‘pendular motion efficiency’ (<I>PME</I>) were determined during walking of the subjects who consist of 37 healthy elderly women (65-85 years) and 21 young women (18-25 years) . Using a force plate, the potential and kinetic energies of the body's centre of mass were measured at various constant speeds. Walking speeds were selected and controlled by a newly devised pace-maker. <I>PME</I>, which is equivalent to ‘% recovery’ by Cavagna (1976), indicates a sort of efficiency in transforming potential energy into kinetic energy and vice versa. The external power to accelerate the body (<I>Wext</I> ), which is thought to be supplied by muscles, increased with walking speed, and the rate of increase in <I>Wext</I> tended to be greater in the elderly than in the young subjects. It was noted that the maximal <I>PME</I> values at the optimum speed in both age groups were comparable, but <I>PME</I> values in the elderly decreased more markedly than in the young subjects as walking speed deviated from the optimum. This fact suggests that an adaptability to different walking speeds reduced in the elderly population.
ABSTRACT
To develop a simple test of endurance capacity in the elderly, we evaluated the reliability and validity of the shuttle stamina walk test (SSTw), in which the running in the shuttle stamina test (SST : 3-minute shuttle running along a 10-meter course) was changed to walking.<BR>We found that: 1) The walking distance in the SSTw was correlated with Vo<SUB>2</SUB>max (r=0.827), 2) the walking distance showed a correlation between the first test and a re-test (r=0.853), 3) the mean peak heart rate during the test was 86.3% of the estimated maximum heart rate with no difference according to age or sex, 4) subjective evaluation of the intensity of exercise was expressed as“fairly light”or“somewhat hard”by 73.7% of the subjects, 5) the results of the SSTw reflected the subjects' self-evaluation of endurance capacity, and 6) the age-related percentage reduction of the walking distance in the SSTw was similar to that in V<SUB>2</SUB>max in subjects aged 40 years and above.<BR>These results suggest that the SSTw, a simple test of endurance capacity that can be performed safely over a wide range of middle-aged to elderly people including those in late old age and those with a low fitness level, has sufficient reliability and validity.
ABSTRACT
The effects of different training programs on the force-velocity relation and the maximum power output from the elbow flexor muscles were examined in eighteen male adults. The subjects were divided into three equal groups (G 30, G 30+0, G 30+ 100) . Training for G 30 was performed with ten repetitions at 30% P<SUB>o</SUB> (P<SUB>o</SUB>: maximum strength), for G30+0 with five repetitions at 30% P<SUB>o</SUB> and five contractions with no load (0 % P<SUB>o</SUB>), and for G 30+100 with five repetitions at 30% P<SUB>o</SUB> and five isometric contractions (100% P<SUB>o</SUB>) .<BR>Maximum power was increased significantly in all groups after training. The amounts of power increase tended to be greatest for G 30+ 100, followed by G 30+0 and G 30. A significant difference was observed between G 30 + 100 and G 30 + 0. Maximum strength increased most in G 30 + 100, followed by G30 and G 30+0. The strength gain in G 30+100 was significantly greater than that in G 30. Maximum velocity increased significantly in all groups. No significant difference in velocity gain was observed between any pair of groups.<BR>These results suggest that isometric training at maximum strength (100% P<SUB>o</SUB>) appears to be a more effective form of supplementary training to increase power production than would no load training at maximum velocity.
ABSTRACT
The effects of different intensities of muscle training on the force, velocity and power relationship have been examined on human elbow flexor muscles. Twenty male subjects, 18-22 years of age, were divided into 4 different groups ; G<SUB>0</SUB>, G<SUB>30</SUB>, G<SUB>60</SUB>, and G<SUB>100</SUB>. Their training loads were prescribed by a fraction of isometric strength (P<SUB>0</SUB>) measured at right angle of elbow joint : 0% P<SUB>0</SUB> (G<SUB>0</SUB> ; isotonic contraction without load), 30% P<SUB>0</SUB> (G<SUB>30</SUB>), 60% P<SUB>0</SUB> (G<SUB>60</SUB>), and 100% P<SUB>0</SUB> (G<SUB>100</SUB> ; isometric contraction) . The subject contracted his elbow flexors with maximum effort 10 times a day, 3 days a week for 12 weeks. The force-velocity relations and the resultant power output were determined, before and after training period, by a modified Wilkie's apparatus.<BR>The training by maximum isotonic contraction without load (G<SUB>0</SUB>) was found to be most effective for improving maximum velocity (V<SUB>0</SUB>), while the isometric training improved isometric strength (P<SUB>0</SUB>) most. For this, the P-V relations of these groups were specifically modified by greater velocity component (G<SUB>0</SUB>) or greater force component (G<SUB>100</SUB>) . The G<SUB>30</SUB> and G<SUB>60</SUB> groups showed such all-round improvements that the P-V relations shifted in parallel with those of pre-training period. The maximum power (PVmax), which calculated from P-V relationship, increased most in G<SUB>30</SUB>, followed by G<SUB>100</SUB>, G<SUB>60</SUB>, and G<SUB>0</SUB> groups.<BR>From these results it was concluded that the different training loads brought about specific effects on P-V relation, and that the most effective load for improving maximum power was 30% of isometric strength.
ABSTRACT
In order to re-evaluate the mechanical efficiency during bicycle pedalling the total mechanical work (internal work + external work) and the energy expenditure were determined on four adult males (20-21 years) . The subject worked on a Monark bicycle ergometer with 6 different loads (0-5kp) at a constant pedal frequency of 50rpm. The internal work (W-int) to accelerate the leg itself was determined by a cinematographic procedure used by Fenn (1930) . With the data of external work (W-ext) and energy expended above resting (E<SUB>t</SUB>-E<SUB>r</SUB>), the‘true’efficiency has been calculated as<BR>‘True’efficiency=W-int+W-ext/E<SUB>t</SUB>-E<SUB>r</SUB>×100<BR>The result obtained was as follows : 1) The time course of kinetic energy due to leg movement was similar to those in walking and running reported previously. 2) The W-int at 0kp ranged in about 70-90kgm/min. In the mean values of four subjects the W-int tend to be constant at the loads from 0 to 3kp (about 80kgm/min), but increased appreciably at higher loads of 4-5k p (about 100-110kgm/min) . 3) The ratios of W-int to W-ext were about 20-30% at lkp, 10-20% at 2kp and 5-10% at 3-5kp. 4) The efficiency of leg movement only at Okp resulted in high values of about 40-85%, suggesting energy transfer between leg and inertia wheel. 5) The efficiency values at 1 to 5kp, ranging in 23.5-36.2%, appeared to show a maximum at intermediate work loads. 6) The‘true’efficiency so calculated did not largely differ from the efficiency calculated by conventional way ; 1.5-4% higher than the work efficiency, 2-5% higher than the net efficiency, and 3-5% higher than the apparent efficiency at intermediate loads.