20) Different points on the velocity curve have been suggested to coincide with the instant of the aortic valve closure: the time point of zero

velocity at the end of the P450 inhibitor nmr systolic wave,21),22) the time point of peak positive acceleration during isovolumic relaxation period,4),23) the time point of zero velocity at the end of the negative spike after the systolic wave.20),24) Based on our results the PSN onset at the level of the AA can be used as a marker of end-systole on the TDI tracings when using the apical longitudinal axis view. The PSN onset at Inhibitors,research,lifescience,medical the level of any segment in the standard four- and two-chamber view is expected to be delayed relatively to the instant of the aortic valve closure and represent the arrival of the PSN velocity Inhibitors,research,lifescience,medical front to the studying segment. Conclusion The concept of the PSN was presented. This distinct velocity pattern interrupts the longitudinal basally directed LV motion during the ongoing protodiastolic relaxation. The relative timing and amplitude reveal its origin to be at the level of the AA. A second PSN spike is present in a substantial amount of healthy subjects predominantly at the AA level. We suggest the first and the second PSN spike to be caused, respectively, Inhibitors,research,lifescience,medical by the myocardial propagation of kinetic energy of the closing aortic valve and retrograde aortic flow which is interrupted at Inhibitors,research,lifescience,medical the instant of the aortic valve closure.

Acknowledgements We thank Lea Dijksman for her statistical support.

A 72-year-old woman visited emergency department

as she suddenly experienced chest pain with resting dyspnea [New York Heart Association (NYHA) functional class IV] while washing dishes at home. She underwent mitral valve replacement 27 years ago, at the age of 45, due to mitral stenosis. Mitral valve replacement was done with Edwards-Duromedics 29 mm mitral valve (Baxter Healthcare Corp., Cleveland, MS, USA). Apart from valvular Inhibitors,research,lifescience,medical heart disease, the patient was on medication for diabetes mellitus and hypertension as well as paroxysmal atrial fibrillation. Thiamine-diphosphate kinase She remained to be the status of NYHA functional class II and anticoagulation with coumadin was appropriately done (international normalized ratio 2-2.5). The recent transthoracic echocardiography (TTE) done 4 month ago confirmed normal left ventricular systolic function [ejection fraction (EF): 69%] and well functioning of prosthetic mitral valve with mild pulmonary hypertension [right ventricle systolic pressure (RVSP) = 35 mmHg] and mild tricuspid regurgitation. On physical examination, she was acutely ill looking, diaphoretic and tachypneic. Her vital signs were as follows; blood pressure 69/51 mmHg, pulse rate 130/min, body temperature 36.7 with respiratory rate 35 breath/min. Her jugular vein was prominently engorged. On auscultation, audible mitral valve click with grade 4/6 pansystolic murmur was noted.