Mayo Clinic Approval Letter For Attachment

October 20, 2011

Bin Mohd Taufik Mohd Farid No 1 Kampung Masjid Lenggeng 71750 Lenggeng Negeri Sembilan Malaysia

Dear Mr. Farid:

As per correspondence with Syahidah Syed Tamin, this is to confirm that you will be welcome as a visitor in the Echocardiography Laboratory in the capacity of an observer for a period of two weeks, December 15, 2011 to December 28, 2011.  Please note that the Clinic is closed on Monday, December 26, 2011.

Please report at 8:00 a.m. on Thursday, December 15th to the Gonda Building, sixth floor front desk and ask for Merri Bremer.  Please bring this letter and a form of personal ID (driver’s license or passport).  She will provide you with a tour of the lab, name badge and then direct you to the Echocardiography Laboratory on Gonda 6.  The echo lab operates 8:00 a.m. to 5:00 p.m. Monday through Friday.

For your use in making hotel accommodations, please use www.rochesterlodging.com .  If you have any questions, please feel free to call me at 507-284-9470 or my fax number is 507-538-3777.  We look forward to your visit.

Sincerely,

Cindy Cunningham

Echo Lab Visitor Coordinator

Gonda 6-138 NW

Mayo Clinic

200 First Street SW

Rochester, MN 55905

507-284-9470

cunningham.cindy@mayo.edu

Aurora St Luke's Medical Centre Milwaukee Wisconsin United States

Tissue Doppler Imaging : Prognostication

Prognostication

Because E/Ea can estimate LV filling pressures and patients with increased filling pressure have higher rates of morbidity and mortality, it is expected that a high E/Ea predicts a poor outcome. E/Ea more than 15 was found to be associated with increased mortality of patients with acute myocardial infarction. By itself, Ea is also a good predictor for clinical outcome. In various clinical conditions, patients who have an Ea less than 5 cm/s are more likely to have much higher mortality than those with an Ea more 5 cm/s.

Tissue Doppler Imaging : Evaluation Of Thick Walls

Evaluation Of Thick Walls

The ventricular walls become thick for several reasons including LV hypertrophy, hypertrophic cardiomyopathy, infiltrative cardiomyopathy, restrictive cardiomyopathy and the athletics heart. These entities can usually be differentiated on the basis of clinical and laboratory findings, but differentiating then can occasionally be difficult. The evaluation of myocardial relaxation with TDI is able to distinguish between a thick athletics normal heart and other disease conditions. Mitral annulus motion is well preserved in the athletic heart because myocardial relaxation is preserved, but it is reduced in all other conditions that have impaired myocardial relaxation.

Tissue Doppler Imaging : Cardiac Time Interval

Cardiac Time Interval

Cardiac time interval are regulated precisely by the mechanics and functions of the myocytes; hence, these intervals are good measure of cardiac function. TDI is well suited for determining the timing of myocardial events. The precise timing of these events is helpful in understanding the mechanism of myocardial relaxation and myocardial suction during early diastolic filling. In healthy heart, in which efficient myocardial relaxation is used effectively to suck blood from LA into the LV during early diastole, the time of onset of mitral inflow (E) coincides with what of myocardial early diastolic motion (relaxation) of the mitral annlus (Ea). However, in hearts with delayed myocardial relaxation and increased filling pressure, diastolic filling (onset of the E wave) depends more on the increased LA pressure and occurs earlier than the onset of the early diastolic motion of the mitral annulus. Therefore, the time interval between the onset of the mitral E velocity and that of the mitral annulus diastolic motion (Ea) increases, and this increased interval has been proposed as a new variables to assess LV filling pressure.

A limitation of measuring cardiac time intervals by pulsed wave Doppler echocardiography is nonstimultaneity because different cardiac cycles are usually needed to measure various intervals which in turn are used together. One solution is to have the capability of obtaining multiple pulsed wave Doppler recordings simultaneously. Another creative means to measure cardiac intervals from a single cardiac cycle is to use tisuue Doppler anatomic colour M-Mode from the anterior mitral leaflets. From this technique, isovolumic contraction time, isovolumic relaxation time, and LV ejection time can be measured reliably from a single cardiac cycle.

Mechanical dyssynchrony is measured by time intervals between peak ejection systolic velocities or peak strain of multiple myocardial segments.

Tissue Doppler Imaging : Tissue Velocity Gradient

Tissue Velocity Gradient

TDI can measure the difference in velocities of adjacent myocardial tissues (velocity gradient), and this can be used to assess the viability and deformation (strain) of the myocardium. The velocity of the endocardium is normally higher than that of the epicardium, thus producing a tissue velocity gradient. In akinetic but viable or nontransmurally infracted myocardium, the myocardial velocity gradient persists, but there is no velocity gradient in scarred or transmurally infarcted myocardium. 

Because days to weeks are needed for myocardial contractility to recover after successful reperfusion of an occluded coronary artery, measurements of the tissue velocity gradient can be useful in patients with an acute myocardial infarction. To record or display the myocardial velocity gradient, the direction of myocardial contractility needs to be aligned in parallel with the direction of the ultrasound beam. Therefore, imaging views are limited to the parasternal windows to image anterior or posterior walls.