It`s Not the Pulse, It`s the Perfusion

     Attack One responds to a report of a man having a heart attack. The call arrives in the late afternoon from a business address. The crew is guided by an anxious security guard to an upstairs office, where they are told "the boss" is having a heart attack. They find a 58-year-old man lying on an office couch, a pillow propping up his legs.

     Crew members address the man quickly. His assistant tells them the patient complained of chest discomfort and light-headedness. He is not responding verbally. He has a cold washcloth on his forehead, but beyond that, his skin is warm and dry. The pulse oximeter counts a very rapid pulse rate, with saturation at 95%. His breathing is regular at 28 times a minute. His blood pressure is palpated at about 110.

     Since the patient is not communicating with them, the paramedics pull out the big patches. They also place the leads for the cardiac monitor. The patient reacts by wincing when the intravenous line is started at his elbow, but continues to be quiet. The assistant chimes in again, reporting that the man has had a recent history of heart problems and recently underwent some tests. He was told he may need some type of surgery, and that had concerned him a great deal. It has been stressful at the office, and all the staff have been putting in long hours. The patient had an abrupt onset of his symptoms just prior to the call for help.

     The cardiac monitor shows a fast heart rhythm, with a rate of almost 190 beats a minute. At that rate, it's hard to determine whether it's a regular or irregular rhythm on the small monitor screen, so crew members utilize the print function to produce a 10-second paper recording. On the paper, it's obvious that this is a regular, narrow-complex rhythm, with a rate of about 190 beats.

     The paramedics weigh their options. Should they shock the patient or attempt to use medication? One decides to include the patient in the decision-making. Noting that the patient has skin that's perfusing well and capillary fill sufficient to produce a good reading on the pulse oximeter, he has reason to believe the patient's brain is also perfusing sufficiently.

     "Sir, your heart is beating very fast, and we need to get it to slow down to make you feel better," he firmly tells the man. "We're trying to decide whether to give you medicine in your vein or apply a big shock across your chest to stop your heart temporarily and then have it return to its normal rhythm."

     The man's eyes open quickly. "You're going to do what?!" he asks.

     With that comment, the victim complied with a decision rule I refer to as Augustine's Law. This rule is derived from an observation that if a patient doesn't refuse the electricity, then he probably needs it.

Prehospital Treatment
     The crew is then able to discuss with the patient the need to correct his fast heart rhythm.

     The patient says he was quite upset about his recent diagnosis of a heart valve problem and having to contemplate corrective surgery for it. Work had been very stressful, and he was drinking more caffeine than usual. With the onset of the fast heart rate, he felt uncomfortable and a little short of breath. He denies having any pain. He says he was so distressed that he doesn't remember what happened until the crew asked him about "getting shocked."

     The paramedics explain they could likely convert the fast, narrow complex and regular rhythm with one or two doses of a medicine that's given in a vein and momentarily stops his heart. The patient remembers having that occur the last time he was in the hospital, and the first dose of the medicine corrected his rhythm. He tells them to proceed.

     The medics prepare the patient for administration of the medication (adenosine), then quickly give the dose in the antecubital vein. The patient's heart rhythm stops for a moment, then returns with a regular sinus rhythm at a rate of about 90 beats a minute. The patient reports feeling much better.

     He is then prepared for transportation, and his trip to the hospital is uneventful. The patient has no further rhythm problems in the emergency department but is admitted for the corrective surgery to his heart valve.

Case Discussion
     Due to the outstanding work of emergency providers and improved heart care, there are an increasing number of patients with chronic heart problems. These patients can present to EMS with complex rhythm problems. Decision-making for patients with these rhythms can be simplified by use of an easy algorithm. The format for decision-making in patients with heart rhythm disturbances is easy to remember if it is presented in a two-by-two box (see Figure 1).

     Abnormal fast rhythms can be narrow-complex or wide-complex and regular or irregular. Each of these four rhythms is managed differently. Narrow-complex rhythms are managed with medicines that interrupt atrial dysrhythmias. The wide-complex regular rhythm is a ventricular tachycardia and may require different medication or electrical cardioversion.

     For any of the fast-rhythm problems, there is a choice of therapeutics. Regardless of the speed of the heart rate, it is the ability of the heart to continue its pumping function that drives the patient to seek help and guides emergency personnel in selecting a treatment. If the heart is continuing to pump effectively and provide for the body's needs, there is no immediate need to change the rhythm. If the patient is suffering significant symptoms, including chest pain, shortness of breath, lightheadedness or syncope, he may need treatment, including medication therapy, to convert to a normal sinus rhythm. Some of these fast heart rhythms are due to volume loss (trauma, bleeding, vomiting); those patients need only volume replacement as a treatment. Others need medication.

     Finally, there are patients in whom the fast rhythm has caused severe compromise of cardiac pump function, which we call perfusion. Perfusion is a combination of many factors, and includes skin color and temperature, mental status, pulse rate and quality, pulse oximetry, blood pressure and respiratory effort. All of these factors combine to give the emergency provider information about how well the heart pump is providing for the needs of the important body organs.

     When very poor perfusion is occurring, mental status is compromised, and the patient becomes lightheaded, anxious and unable to process thoughts correctly. This can progress to unconsciousness. When perfusion deteriorates to this level, the patient needs electrical conversion of the heart rhythm.

     It's not the heart rate that matters, it's the ability of the heart pump to function. Remember, "It's not the pulse, it's the perfusion," or, alternately, "It's not the beat, it's the motion."

     Observing this across many patients, emergency providers note that poorly perfusing patients have abnormal mental statuses. Those mental status changes drive decisions in care, which brings us back to Augustine's Law. Once again: If a patient doesn't refuse the electricity, he probably needs it.

     It is also notable that very slow rhythms present similar diagnostic dilemmas and pose the same three choices of therapy. For any slow rhythm, the emergency provider will choose between doing nothing, administering drugs or applying electricity (in this case, cardiac pacing). So for very slow rhythms:

• If the patient is perfusing well, he needs nothing.
• If the patient is perfusing poorly but his mental status is still clear, use an appropriate drug to treat.
• If the patient is perfusing poorly and does not resist you, treat with emergency cardioversion.

James J. Augustine, MD, serves on the clinical faculty in the Department of Emergency Medicine at Emory University, Atlanta, GA. He also serves as Medical Director for the Atlanta Fire Department, which includes operationsat Atlanta Hartfield Jackson International Airport. He has served 23 years as a firefighter and EMT-A, and is a member of EMS Magazine's editorial advisory board. Contact him at jaugust@emory.edu.