that some doctors were reluctant to give adenosine in the emergency setting. He was still staring. âWeâll give her 6 milligrams of adenosine by rapid IV push and see if we can get her back into sinus rhythm.â He paused and she nodded to indicate that she understood that there was always the chance that the patient might develop a life-threatening arrhythmia. âSo weâll just have this within grabbing distance,â she said quietly, moving the defibrillator next to the trolley. Then she prepared the drug and handed it to Christian, who checked it and inserted the syringe into the venflon. âWhatâs happening?â Ellen moaned, rubbing her hand over her chest. âWhatâs happening?â âEllen, the conduction system of your heart isnâtworking properly and your heart is being overstimulated. Thatâs why youâre feeling the way you are. The drug Iâm giving you should prevent some of the electrical impulses getting through and slow the heart.â Christian depressed the syringe to push the drug into the vein then dropped the empty syringe onto the tray next to him. âIâll do you a rhythm strip,â Lara said, programming the ECG machine and then standing to one side so that he could see the printout. Ellen gave a sigh. âIâm feeling a bit better. But my face feels really hot.â âThatâs a side effect of the drug we just gave you. Nothing to worry about.â Christianâs gaze flickered to the monitor. âIâm going to refer you to the cardiologists, Ellen. Theyâll want to do some more tests.â âDo you know whatâs wrong?â He looped the stethoscope back around his neck. âThe electric currents that control your heart arenât working properly. Put simply, theyâre taking a short cut.â âIâm a lawyer. I donât need the simple version.â Christian studied her for a moment. âAll right.Do you know anything about normal conduction pathways in the heart?â âNo, but Iâm a fast learner.â Christian pulled a piece of paper and a pen out of his pocket and swiftly drew a diagram. âIn the normal heart, electrical impulses start in the sinoatrial node in the right atriumâthe atria are the chambers at the top of your heartââ his pen flew over the page to illustrate his point ââand pass through the atrioventricular node to the ventricles in the bottom of your heart. The atrioventricular node limits the electrical activity that passes through to the ventricles and acts as a break on the heart rate. Thatâs what happens in the normal heart.â Ellen looked at the drawing and gave a hollow laugh. âAnd thatâs not me, right?â âSometimes thereâs an extra electrical pathway that bypasses the normal process and conducts electricity at a higher rateâthereâs no filter, if you like. The result is that the heart can beat very quickly and that causes the symptoms you felt today.â Lara studied the ECG again. âIf she has an accessory pathway, why does the QRS complex look normal?â âBecause ventricular depolarisation can occur through the normal pathway. Itâs a combination of pre-excitation and normal conduction.â âYouâve lost me.â Ellen sighed. âSo how did I get this extra pathway? Was I born with it?â âYes, itâs congenital. Some people have more than one. Basically it happens when the atria and the ventricles fail to separate completely.â âBut why hasnât it been picked up before?â âBecause the majority of the time the normal pathway is used.â âAnd can it be fixed?â âExtremely successfully.â Christian folded the ECG strip and attached it to the notes. âWeâll refer you to the cardiologists and theyâll carry out electrophysiological