Background We aim to investigate the effect of utilizing aortic valve timing in the measurement of cardiac magnetic resonance (CMR)-derived ejection fraction (EF). Although CMR-derived left ventricular (LV) EF is the gold-standard for volumetric evaluation of the heart, it always reports higher values when compared to other modalities such as echocardiography and radionuclide ventriculography. ...

Aortic stenosis is 1 of the most common heart valve diseases among adults. When symptoms develop, prognosis is poor, and current guidelines recommend prompt aortic valve replacement. Depending of the severity of the aortic stenosis and the presence of concomitant heart disease and medical comorbidities, stress testing represents a reasonable strategy to help better risk stratify asymptomatic pa...

In patients with heart valve disease, echocardiography is the mainstay for diagnosis, assessment and serial surveillance. However, other modalities, notably cardiac MRI and CT, are used if echocardiographic imaging is suboptimal but can also give complementary information to improve assessment of the valve lesion and cardiac compensation to aid the timing of surgery and determine risk. This sta...

Background/Introduction The indications for urgent valve replacement in patients with infective endocarditis (IE) include uncontrolled infection, recurrent emboli, valve dysfunction and cardiac failure. The optimal timing of this surgery when IE is complicated by cerebrovascular events (such as cerebral infarction or haemorrhage) is controversial, largely due to the escalated risk of perioperat...

Systolic pressure in the pulmonary artery was estimated from the interval between pulmonary valve closure and tricuspid valve opening, and the heart rate using a nomogram previously described. The timing of valve movements was recorded by Doppler ultrasound. The estimated pressure correlated well with that obtained at catheterisation in 45 of 48 patients with pulmonary hypertension. Instantaneo...

In Part I of this article, several aspects of valve structure and function and their possible clinical relevance were discussed. We now review the clinical evolution and application for various forms of valve repair and outline some of the factors relating to the timing and choice of particular types of repair or replacement and, whenever appropriate, repair versus replacement. In addition, fut...

This work presents passive time delay valves for micro channels in two different working modes for microfluidic on chip timing. The delay valve designs are compatible with conventional lamination techniques for microfluidics and allow to pre-program advanced sequential operations independent from the geometries of the microfluidic system. The time delay of the dissolvable valves ranges from 1.2...

In this paper, the influence of the gas exchange process on the diesel engine thermal overload is provided. Main components involved in the gas exchange process are discussed. The ambient conditions, the turbocharger performance, and the valve timing that affect the gas exchange process have been investigated. Experiments were conducted to simulate ambient conditions at different geographical l...

In this paper, a Rankine cycle test system is established to recover exhaust energy from a 2.0 L gasoline engine. Experiments on the system’s performance are carried out under various working conditions. The experimental results indicate that the recovery power of the expander is strongly related to the load and speed of the gasoline engine. It is found that when the output power of the gasolin...

f all valve lesions, mitral stenosis has the most options for ntervention and in many ways is the valve lesion where it is asiest to make a decision that intervention is necessary. his was the first acquired valve lesion where patient ymptoms and ultimate prognosis could be improved surgially even before cardiopulmonary bypass was available. The ndications for the timing of valve repair or repl...