Assessing the cardiac valves conditions in athletic horses with poor performance.

Heart murmurs and valvular regurgitation are common in horses and often have no effect on their performance. However, when structural changes occur in the heart size, they can affect performance adversely. This study aimed to examine the correlation between cardiac valves disease and poor performance in athletic horses. A total of 300 athletic Thoroughbred and mix-breed horses including 164 mares and 136 stallions, with a history of poor performance, were selected. Horses with cardiac murmurs were identified and further cardiac examination including precise auscultation, base-apex electrocardiogram for possible dysrhythmias at rest and after exercise, echocardiographic and hematological tests were conducted in two stages. The first was at admission time and the second examination was done four to six months later to evaluate the outcome of the possible disorders. Respiratory system and musculoskeletal diseases were diagnosed respectively in 93 and 149 out of 300 examined horses and 36 horses showed heart murmur without any other complications. Echocardiography was performed in horses with heart murmur and 25 of them showed regurgitation of the cardiac valve. During the first examination, 7 horses were diagnosed with regurgitation and changes in the size of cardiac chambers, whereas this number increased to 25 during the second examination. There was no significant relationship between degree of murmur and severity of regurgitant jet in horses. The valvular regurgitation can affect the performance when causing changes in the size of the cardiac chambers which can consequently jeopardize the athletic future of the horse.

Dependence of electron transfer dynamics on the number of graphene layers in π-stacked 2D materials: insights from ab initio nonadiabatic molecular dynamics.

Recent time-resolved transient absorption studies demonstrated that the rate of photoinduced interfacial charge transfer (CT) from Zn-phthalocyanine (ZnPc) to single-layer graphene (SLG) is faster than to double-layer graphene (DLG), in contrast to the expectation from Fermi's golden rule. We present the first time-domain non-adiabatic molecular dynamics (NA-MD) study of the electron injection process from photoexcited ZnPc molecules into SLG and DLG substrates. Our calculations suggest that CT occurs faster in the ZnPc/SLG system than in the ZnPc/DLG system, with 580 fs and 810 fs being the fastest components of the observed CT timescales, respectively. The computed timescales are in close agreement with those reported in the experiment. The computed CT timescales are determined largely by the magnitudes of the non-adiabatic couplings (NAC), which we find to be 4 meV and 2 meV, for the ZnPc/SLG and ZnPc/DLG systems, respectively. The transitions are driven mainly by the ZnPc out-of-plane bending mode at 1100 cm-1 and an overtone of fundamental modes in graphene at 2450 cm-1. We find that dephasing occurs on the timescale of 20 fs and is similar in both systems, so decoherence does not notably change the qualitative trends in the CT timescales. We highlight the importance of proper energy level alignment for capturing the qualitative trends in the CT dynamics observed in experiment. In addition, we illustrate several methodological points that are important for accurately modeling nonadiabatic dynamics in the ZnPc/FLG systems, such as the choice of surface hopping methodology, the use of phase corrections, NAC scaling, and the inclusion of Hubbard terms in the density functional and molecular dynamics calculations.

Echocardiographic measurement of cardiac valvular thickness in healthy cows, cows with bacterial endocarditis, and cows with cardiorespiratory diseases.

OBJECTIVE: To determine valvular thickness in healthy cows, cows with bacterial endocarditis, and cows with various cardiorespiratory diseases. ANIMALS: 40 healthy Holstein adult cows (CONTROL), 6 adult cows with confirmed bacterial endocarditis (BE), and 10 cows with other cardiorespiratory disorders (NONBE). METHODS: Prospective study using right transthoracic echocardiographic examination in CONTROL, BE and NONBE cows. The valvular thicknesses of all cows were assessed in four different locations for all cardiac valves, and the maximal value was used for further analysis. RESULTS: The mean [±standard deviation (SD)] maximal thicknesses of the tricuspid, mitral, aortic, and pulmonary valves in the CONTROL group were 0.69 ± 0.10 cm, 0.85 ± 0.21 cm, 0.72 ± 0.17 cm, and 0.58 ± 0.12 cm, respectively. The maximal valvular thicknesses were less than 0.97 cm for the tricuspid, less than 0.91 cm for pulmonary, less than 1.05 cm for the aortic, and less than 1.28 cm for the mitral. In BE cows, the maximal valvular thickness of affected valves (median: 4.22 cm; range: 2.52-6.97 cm) and non affected valves (median: 0.75 cm; range: 0.45-1.52 cm) were significantly different (P = 0.0004). The maximal valvular thicknesses of the NONBE valves as well as the unaffected valves in the BE group were not significantly different compared to the CONTROL group valves. CONCLUSIONS: Using the mean ± 2SD formula for each valve in healthy cows, a thickness of tricuspid, mitral, aortic or pulmonary valves greater than 0.85 cm, 1.27 cm, 1.06 cm or 0.82 cm respectively should raise the suspicion of valvular bacterial endocarditis.

Effect of lactation on functional and morphological echocardiographic variables in adult dairy cows.

OBJECTIVES: To study the effect of pregnancy and lactation on echocardiographic parameters in Holstein dairy cows. ANIMALS: Nine multiparous high milk producing (HMP) dairy cows (producing more than 40 kg of milk per day in peak production) and 9 low milk producing (LMP) cows (producing less than 30 kg or milk per day in peak production). METHODS: Echocardiography was performed twice; one month before calving and two months after calving. RESULTS: The heart rate of HMP cows in the early lactation period was significantly higher than in the dry period. In LMP cows, there was a significant increase in left ventricular dimension in the early lactation period as compared to the dry period, and the interventricular septum in systole (IVSs) in the dry period was significantly thicker than early lactation period. In HMP cows, there was an increase in the right ventricular diameter in systole in the early lactation period as compared to the dry period. Left ventricular and aortic dimensions in the dry period of HMP were significantly higher than those of LMP cows. When the data were corrected for body weight, comparison of values of the dry period of HMP and LMP cows showed that left ventricular volume in systole in HMP was significantly higher and that IVSs, left ventricular fractional shortening and ejection fraction were significantly lower than in LMP cows. CONCLUSIONS: This study demonstrated that lactation influences the intracardiac dimensions. The amount of milk production can influence echocardiographic parameters in dairy cows.

Echocardiographic findings of tricuspid blood cyst mimicking bacterial endocarditis in a dairy cow.

The most common endocardial disease in cattle is bacterial endocarditis. The diagnosis of the disease in living animals is mainly based on clinical findings and echocardiographic detection of an irregularly thickened valve. Despite its presumed good sensitivity, little is known on the specificity of transthoracic echocardiography with regards to endocarditis. This case report describes the echocardiographic findings in a dairy cow diagnosed with a chronic inflammatory process, liver and splenic abscesses and tricuspid valve blood cysts that can be mistaken for bacterial endocarditis, thus emphasizing the need to improve antemortem diagnostic tools for endocarditis in cattle.

Heart disease in cattle: diagnosis, therapeutic approaches and prognosis.

Heart disease in cattle remains medically challenging both to diagnose and to treat. This is in part due to its low incidence in the bovine species but also because the prognosis is typically guarded to poor. The majority of published data concerning bovine heart disease are case studies and case reports. The aim of this article is to review the evidence-based medicine on the principal heart diseases of cattle (pericarditis, bacterial endocarditis, congenital heart defects, cor pulmonale, dilated cardiomyopathy and heart neoplasms), with emphasis on their diagnosis, prognosis and treatment.