S4

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S4

Symbol for fourth heart sound.

S4

the fourth heart sound in the cardiac cycle. It occurs late in diastole on contraction of the atria. Rarely heard in normal subjects, it indicates an abnormally increased resistance to ventricular filling, as in hypertensive cardiovascular disease, coronary artery disease, cardiomyopathy, and aortic stenosis. A left-sided fourth heart sound, it may be heard with the stethoscope's bell at the apex of the heart during expiration. Also called atrial gallop, physiological fourth heart sound.

S4

1. Fourth heart sound, which corresponds to atrial contraction during presystole; it is rarely heard in normal hearts.

S4

Abbreviation for fourth heart sound.
References in periodicals archive ?
Luna expects to file an amendment to the Form S-4 in March 2015, and following the effectiveness of the Form S-4, Luna and Advanced Photonix will mail the joint proxy statement/prospectus included in the Form S-4 to their stockholders for consideration at their respective stockholder meetings.
The command team is led by cither an Air Force lieutenant colonel or a Navy commander; the PRT commander's branch of service will coincide with the branch of the enlisted personnel in the S-l, S-4, S-6, and information operations staff sections.
To ensure seamless communication between the battlespace owner and the PRT command team, the S-3, S-4, and first sergeant positions are active-duty Army personnel.
We calculate Consolidated Adjusted EBITDA as earnings before interest expense, depreciation and amortization, income taxes and other adjustments described in the Form S-4 under "Management's Discussion and Analysis of Financial Condition and Operating Results - Non-GAAP Measures".
In connection with the proposed merger, Sand Hill filed, with the SEC on December 16, 2005, a proxy statement and prospectus on Form S-4 that contain important information about the proposed merger.
Additional information regarding these directors and executive officers is also included in Lawson's proxy statement, which was also filed as part of the Form S-4 submission filed with the SEC.
Investors should read the Form S-4 and proxy statement carefully before making any voting or investment decision.
In addition to the Form S-4 filed on November 7, 2005, DPAC has previously filed Forms 8-K or 8-K/A on April 27, 2005, August 9, 2005, and October 20, 2005 containing the current agreements between DPAC and QUATECH.
On December 12, 2005, UCBH filed with the Securities and Exchange Commission ("SEC") a registration statement on Form S-4 containing a prospectus for the shareholders of Great Eastern Bank.
Donnelley's and Dex Media's results to differ materially from those described in the forward-looking statements are described in detail in the registration statement on Form S-4 that R.
That proxy statement is contained in a registration statement on Form S-4 first filed by Potlatch Holdings on September 19,2005, and both companies have filed other relevant documents concerning the proposed merger transaction with the Securities and Exchange Commission (SEC).