Updated from 2:26 p.m. EDT

Shares of

Cardiac Science

( DFIB) were among the worst-performing health and pharmaceutical stocks Friday after the company posted second-quarter results that missed expectations and warned that third-quarter results would fall below expectations as well.

The maker of defibrillators posted a loss of 7 cents a share on sales of $17.5 million. Analysts polled by Thomson First Call had expected it to post a loss of 4 cents a share on sales of $17.5 million. Looking ahead, it expects to report a third-quarter loss of 4 cents to 6 cents a share, wider than the loss of 2 cents a share analysts had been expecting. Sales, meanwhile, are now expected to be $16.5 million to $18.5 million. Analysts were looking for $18.8 million. Shares of Cardiac Science traded down 85 cents, or 29.6%, to $2.02.

Viasys Healthcare

( VAS) fell after it reported weaker-than-expected second-quarter earnings. Excluding items, the health care technology company posted earnings of 13 cents a share on sales of $95.4 million. Analysts had expected it to earn 22 cents a share on sales of $104.7 million. Looking ahead, the company said that first- and second-quarter results lead it to believe that full-year earnings and sales will be equal to results from 2003. Shares of Viasys Healthcare traded down $3.48, or 18.7%, to $15.15.

Shares of

Gilead Sciences

(GILD) - Get Report

rose after the company reported blowout second-quarter earnings and sales. The biotech company posted earnings of 49 cents a share on sales of $319.7 million. Analysts had predicted that it would earn 36 cents a share on sales of $285.8 million. A year ago it earned 46 cents a share on sales of $238.9 million. Shares of Gilead Sciences traded up $5.14, or 8.6%, to $64.64.

Staar Surgical

(STAA) - Get Report

fell after it reported weaker-than-expected second-quarter earnings and sales and warned that full-year results would fall short of expectations. The medical device maker posted a second-quarter loss of 18 cents a share on sales of $12 million. Analysts had expected a smaller loss of 7 cents a share on sales of $13.8 million. Looking ahead, Staar expects a full-year loss of 52 cents to 55 cents a share, substantially higher than the loss of 20 cents that analysts were expecting. Shares of Staar Surgical traded down 72 cents, or 12%, to $5.29.

Shares of

Cytyc

( CYTC) rose after the company turned in better-than-expected second-quarter earnings. The medical device company earned 19 cents a share on sales of $99.5 million. Analysts had expected it to earn 18 cents a share on sales of $98.7 million. Strong sales of NovaSure, which is used to treat excessive menstrual bleeding, fueled the second-quarter results. Shares of Cytyc traded up $2.31, or 10.6%, to $24.10.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, up 3 cents to $31.96;

Bristol-Myers

(BMY) - Get Report

, up 33 cents to $22.90;

Amgen

(AMGN) - Get Report

, down 1 cent to $56.99;

Boston Scientific

(BSX) - Get Report

, up 99 cents to $38.26;

Schering-Plough

( SGP), down 7 cents to $19.46; and

Genentech

( DNA), up 55 cents to $48.68.