Robin Cook - Marker

It wasn't until almost three A.M. that Henry came out of the room, snapped off his latex gloves, and removed his mask. He was a rotund Asian man with flawless skin and dark, closely cropped hair. He snapped up Jack's hand and pumped it enthusiastically as Shirley introduced them. Shirley mentioned the quandary about the short EKG segment, and Jack handed over the page from Sobczyk's chart with the tracing attached.

"I see, I see," Henry said, nodding his head and smiling as he glanced at the EGK strip. "Very interesting. Is this all we have?"

"I'm afraid so," Jack said. He recounted the brief story, as he knew it, concerning the failed resuscitation attempt. He added why he thought that even a guess on their part might be helpful.

"It's dangerous to say too much with so little," Henry said while again studying the tracing. He then looked up at Shirley. "Dr. Mayrand, perhaps you could tell us what you were thinking?"

Shirley reiterated what she had said to Jack about the various waves, intervals, and complexes while Henry continued to nod. When Shirley had finished, Henry asked her if she had any idea of what might have accounted for such alterations.

"The conduction system seems to be failing," Shirley said. "Perhaps that means the sodium pumps within the cells of the bundle of His are not functioning or perhaps overwhelmed, resulting in a deleterious alteration in membrane potentials."

Jack again gritted his teeth. He had a sudden urge to throw a tantrum. Shirley's short monologue painfully reminded him of the academic gibberish he'd endured in medical school. In the grip of coffee-enhanced anxiety, Jack had little tolerance for such didactic mumbo jumbo and was about to make his impatience known when Henry took the words out of his mouth.

"I think Dr. Stapleton is interested in some particular agent that might account for what we are seeing on this short strip of EKG. Am I correct, Dr. Stapleton?"

Jack nodded enthusiastically.

"Well," Shirley said, visibly uncomfortable in being put on the spot, "I'm sure there are a number of drugs that could create this type of picture, including toxic amounts of most of the arrhythmia drugs. But I think it could have possibly been caused by a sudden electrolyte imbalance, particularly potassium or calcium. But that's about all one could say."

"Well said," Henry complimented. He handed the page from Sobczyk's chart with the EKG tracing back to Jack.

Jack took the paper from Henry, mulling over what Shirley had said. She hadn't added anything new, but the words "sudden electrolyte imbalance" gave him an idea. The reason he and others had dismissed the possible role of potassium was because the lab had reported that the victims' potassium levels had all been normal. Now that Jack thought about it, what the lab was saying specifically was that the postmortem potassium levels were normal. As everyone knew, potassium levels soar after death because the body's vast potassium store is intracellular and is maintained by an active transport system. After death, the transport system stops and the potassium immediately leaks out. Any sudden increase in potassium in an individual by an injected bolus prior to death would be effectively masked. Jack had to admit that if someone wanted to kill off patients, it would be an insidiously clever way to do it.

"If you happen to find any additional EKG recordings, let us know," Henry was saying. "Perhaps we could be more definitive with more leads. Just let us know."

"One other thing," Jack said, catching sight of Laurie's two Post-its attached to the back of the page. "Do either of you know what this laboratory test is?" He pulled off the Post-it with "MASNP" written on it and handed it to Henry. Henry glanced at it, shook his head, and looked at Shirley. Shirley shook her head as well.

"No idea," Henry said. He handed the piece of yellow paper back to Jack. "But I know someone who probably would: David Hancock, the night lab supervisor. The lab's conveniently right down the hall." Henry pointed to a door no more than twenty feet away. "I know he's here tonight, because he helped me earlier."

Jack took back the Post-it and reattached it to the page next to the other one. With the lab so close, he thought it would be worth taking the time to duck in and see if David Hancock was available.

"I don't know what kind of test an MASNP is, but I do know what MEF2A is," Henry said, catching sight of the second slightly wrinkled Post-it.

"Oh?" Jack questioned. He wasn't even sure where Laurie had come up with the acronym.

"That's a gene," Henry said. "It produces a protein that controls the cascade of events that assures the health of the coronary arteries' inner lining."

"Interesting," Jack said vaguely, wondering how it could be associated with Laurie's series, or if it was associated at all. "What would a positive MEF2A mean?"

"Now, that's a bit misleading," Henry admitted. "When they write 'positive MEF2A in the literature, what they really mean is positive for the marker for the mutated form of MEF2A. In that case, it is someone who produces a defective protein and, as a consequence, will have a high probability of experiencing coronary artery disease, such as my patient tonight. He's positive for the MEF2A marker, and here he is, having had an acute myocardial infarction, even though we've tried to avoid it by keeping his LDL cholesterol as low as possible."

"Well, I'm sure this will all be helpful," Jack said, although in reality he had no idea. When he got back to the Manhattan General and got to see Laurie, he'd have to ask her about where she'd found the acronym and then, if appropriate, tell her what he'd learned.

Jack thanked both Henry and Shirley, and quickly headed down toward the laboratory door, hoping David Hancock would be conveniently available. As he entered the lab, he glanced at his watch, and his level of anxiety inched upward. It was twenty-two after three.

Laurie pressed the nurse's call button several more times. She had lost count of how many times she had pressed it since Jazz had left, and the fact that no one responded made her feel even more vulnerable. It occurred to her that Rakoczi was being purposefully passive-aggressive, as she had suggested she might be when she'd left. Laurie looked down at her hand holding the call button. She was shaking.

To add to her anxiety, Laurie's pain from her surgery had gotten worse, particularly after moving herself from the gurney to the bed and then lifting the telephone. Earlier, she felt it only when she moved, but now it was constant. There was no doubt that she needed some analgesia, but she was reluctant to ask for it because of the inevitable hypnotic effects. Under the circumstances, Laurie didn't want to be any more obtunded than she was already. She had to keep her wits if she was to have any chance of protecting herself until Jack got there.

Just when Laurie had decided to see what it would be like for her to get out of bed and stand up, someone came sweeping into the room. It wasn't Jazz or Elizabeth. It was another woman even more swarthy than Jazz, with long, straight, black hair held back with a clip. She carried a large tray by its handle. The tray was divided into numerous cubbies filled with blood tubes, syringes, and the like.

"Laurie Montgomery?" the woman questioned while glancing at a requisition form.

"Yes," Laurie said.

"I need to draw some blood for some clotting studies." The woman put her tray on the foot of Laurie's bed, took out the proper color-coded stoppered tubes, and came alongside Laurie, dangling a tourniquet.

"I need a telephone," Laurie said as the woman picked up Laurie's arm and began searching for veins and patting those she saw to check if they'd be appropriate for venipuncture. "The one here by my bedside doesn't have a dial tone."