The concentric hypertrophy is due to the increased left ventricular pressure overload associated with AI, while the eccentric hypertrophy is due to volume overload caused by the regurgitant fraction.Physiologically, in individuals with a normally functioning aortic valve, the valve is only open when the pressure in the left ventricle is higher than the pressure in the aorta. This allows the blood to be ejected from the left ventricle into the aorta during ventricular systole. The amount of blood that is ejected by the heart is known as the stroke volume. Under normal conditions,  >50% of the blood in a filled left ventricle is ejected into the aorta to be used by the body. After ventricular systole, the pressure in the left ventricle decreases as it relaxes and begins to fill up with blood from the left atrium. This relaxation of the left ventricle (early ventricular diastole) causes a fall in its pressure. When the pressure in the left ventricle falls below the pressure in the aorta, the aortic valve will close, preventing blood in the aorta from going back into the left ventricle. Diagnosis
In terms of the diagnosis of aortic regurgitation a common test for the evaluation of the severity is transthoracic echocardiography, which can provide two-dimensional views of the regurgitant jet, allow measurement of velocity, and estimate jet volume. The findings in severe aortic regurgitation, based on the 2012 American College of Cardiology/American Heart Association guidelines include:

Chest X-ray can assist in making the diagnosis, showing left ventricular hypertrophy and dilated aorta.
On the other hand, a white blood cell count is the only laboratory test that may indicate the presence of an abscess. Some of the imaging tests are more commonly used to diagnose this condition. Abdominal CT scans, MRIs and ultrasounds are helpful in providing clear images of the inside of the abdomen and successfully used in the diagnosing process. These tests may reveal the presence of infected necrosis which has not yet developed into an abscess and as a result, doctors usually order repeated imaging tests in patients with acute pancreatitis whose abdominal pain worsens and who develop signs of abdominal obstruction. Also, it is recommended that patients who have a prolonged clinical response are tested repeatedly as a prevention method to avoid the development of an abscess that may rupture. Prevention
In some cases, abscesses may be prevented by draining an existing pseudocyst which is likely to become inflamed. However, in most cases the developing of abscesses cannot be prevented. Treatment
Antibiotics are commonly used as a curing method for pancreatic abscesses although their role remains controversial. Prophylactic antibiotics are normally chosen based on the type of flora and the degree of antibiotic penetration into the abscess. Pancreatic abscesses are more likely to host enteric organisms and pathogens such as E. coli, Klebsiella pneumoniae, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, and Streptococcus species. Medical therapy is usually given to people whose general health status does not allow surgery.