Missing the beat: failure to diagnose heart attack cases.

Each year nearly 1.5 million people in the United States suffer an acute (sudden) myocardial infarction (MI), or heart attack.(1) Over the past several decades deaths from heart attacks have decreased significantly due to the public's increased awareness of risk factors, advances in hospital coronary care, and advances in cardiopulmonary resuscitation techniques.(2) About 25 percent of those who suffer an acute MI die, and about one-half of those deaths occur before the patient reaches the hospital.(3)

Medical negligence cases based on a failure to diagnose or treat a heart attack are complicated, legally and medically. Before taking on a case, it is helpful to have an understanding of heart disease and its risk factors; heart attacks; and the medical terms, practices, and technology common to heart attack cases.

A heart attack is caused by oxygen deprivation to the heart, called acute myocardial ischemia. There are essentially two causes of death in acute heart attack cases. One is a fatal abnormal heartbeat (arrhythmia). The second is the failure of the heart as a pump caused by damage to the heart wall. About 5 percent to 10 percent of all heart attack survivors die in the first year after the attack.(4)

The risk factors for developing coronary heart disease are: male gender, advanced age, elevated blood cholesterol, high blood pressure, diabetes mellitus, cigarette smoking, history of premature atherosclerosis (hardening of the arteries), family history of coronary artery disease, and obesity. Obesity is listed because it aggravates high blood pressure, hyperlipidemia (or fat in the blood), and high blood cholesterol.

Acute Myocardial Infarction 

Acute myocardial infarction is the result of a prolonged lack of oxygen to the heart muscle. It is usually caused by the total blockage of a coronary artery, which supplies the heart with oxygen-filled blood.(5) Three main things can cause this: a blood clot (thrombus), atherosclerosis, and coronary artery spasm. Any one of these can lead to death (infarct) of the heart tissue or an abnormal heartbeat.

The goal of treatment for an acute myocardial infarction is to decrease stress on the heart and restore blood supply to the affected area. There are several ways to do this.

* Medical management--using medications to decrease the heart muscle's demand for oxygen-rich blood. Some medications can reduce oxygen consumption by decreasing stress on the heart or dilating the vessels to allow greater blood flow. Other drugs can increase the efficiency of the heart by helping it keep a normal rhythm. Aspirin can decrease clot formation.

* Thrombolytic therapy--using drugs to break up a blood clot. These drugs can be given either intravenously or directly into the heart's blood vessels.

* Percutaneous transluminal coronary angioplasty--commonly called balloon angioplasty. In this procedure, a catheter is inserted into the blocked blood vessel, and a balloon is inflated at the area of the narrowing, opening the vessel.

* Coronary artery bypass surgery.

Successful restoration of the blood supply to the heart depends on timely diagnosis of a myocardial infarction or ischemia. An infarction is not a point-in-time event, but evolves over a period of time. The physician's choice of treatment is based on the patient's history and risk factors.

Medical management may be done where the damaged area is so small that the risks of surgical intervention outweigh the benefits. Also, if the damage is so severe that surgery would not improve the patient's condition, medical management may be the best choice.

Studies have shown that thrombolytic therapy should be given within 24 hours after a patient shows the first signs of acute myocardial infarction in order for it to be effective in decreasing morbidity and mortality risks. Streptokinase was the first thrombolytic therapy drug to be used. Results of a blind study showed an 18 percent decrease in hospital mortality in a group of patients who were given the drug.(6)

Another drug, tissue plasma activator (TPA), which is normally secreted by the walls of the arteries, is more effective in achieving breakup of the clot (lysis) than streptokinase is.

Neither of these drugs should be used if a patient has had a stroke, transient ischemic attack, recent bleeding of the gastrointestinal tract, other incidents of serious bleeding, or surgery. The drugs also should be avoided if the patient has severe high blood pressure (greater than 180/110).(7)

Thrombolytic therapy should be considered in patients who have had an acute myocardial infarction four to six hours after the onset of chest pain.(8) Therapy should be restricted to those who have had at least 30 minutes of chest pain and ST wave elevation in two different electrocardiographic leads.(9)

Angioplasty should not be attempted unless the risks are equal to or less than those associated with coronary artery bypass surgery or medical management.(10) And the risks should be considered in terms of both early and long-term results. An example of the former would be successful dilation of an artery. Examples of the latter would be the patient's survivability or need for additional surgery.

Sudden blockage of the artery (acute occlusion) is the major risk associated with balloon angioplasty. This risk is increased if the narrowed (stenotic) Dart of the artery has a length of two or more luminal diameters, the patient is a woman, the area to be opened up is at a bend or branch in the artery, several narrowings in one artery need to be opened up, or several arteries need to be opened by the procedure.(11)

Coronary bypass surgery is another method to restore blood supply to the heart. The Coronary Artery Surgery Study (sponsored by the National Heart, Lung & Blood Institute) was the third randomized trial studying the efficacy of this surgery. The initial general conclusion was that in patients with mild stable chest pain, surgery did not offer advantages in survival when compared to medical management.

Critics of the study noted that most patients undergoing surgery did not meet the criteria set by the study. Subsequent studies have shown minimal change in the survival rate of patients who receive medical management (not including thrombolytic therapy) and a striking change in the rate of survival for patients who undergo surgery.

Coronary bypass should not be done on vessels with less than a 50 percent narrowing because it is not needed. Most physicians will defer surgery until stenosis reaches 70 percent.(12) Recent studies show that bypass grafts stay open longer if an internal mammary artery is used instead of a leg vein.(13)

The Emory Angioplasty Surgery Trial compared balloon angioplasty and bypass surgery and found that the procedures did not differ significantly with respect to the occurrence of the composite primary result. Consequently, the selection of one procedure over the other should be gruded by patient preferences, including the need for subsequent procedures.(14)

Another study examined patients with significant narrowing limited to the left anterior descending coronary artery who underwent balloon angioplasty or bypass surgery. According to this study, angioplasty was at least initially successful in 93 percent of cases. In 3 percent of these, performing emergency bypass surgery was later necessary.

After five and a half years, 97 percent of patients who had undergone angioplasy were alive, compared with 93 percent of patients who had had surgery. But patients who had had surgery had higher percentages of freedom from chest pain and heart damage and less need for further intervention. Both procedures are effective in decreasing mortality and morbidity, but patients undergoing angioplasty are likely to require repeat angioplasties to achieve this.(15)

Heart Attack Symptoms

Heart attacks have many symptoms, including:

* Pain. A physician should ask about the pain's location, radiation, and quality. The doctor should also ask how long the pain has been present, how long it lasts, and what causes it or relieves it.

Chest pain is usually indicative of atherosclerotic coronary heart disease and occurs when the disease reaches a critical degree of severity and the centers of the heart's arteries (lumen) become sufficiently narrowed to cause a lack of blood flow to the cardiac muscle. It occurs when the amount of blood flow is not sufficient to meet the demands of the heart, or if a muscle spasm or blood clot blocks the flow.

Pain that is brief is called angina. The pain may radiate to the neck, jaw, hard palate, tongue, left arm, right arm, shoulder, elbow, wrist, back, or upper part of the abdomen.

* Shortness of breath (dyspnea). The doctor should ask the patient about the factors that cause this and relieve it and whether the shortness of breath is accompanied by wheezing or other respiratory symptoms. Dyspnea is always abnormal if it occurs with slight exertion or when a patient is at rest.

* Bluing of the skin (cyanosis). For cyanosis to be present, the oxygen saturation must be less than 85 percent. If a patient is anemic or has low hemoglobin, cyanosis may not be evident.(16)

* Other symptoms. Cough, palpitations, dizziness (syncope), swelling (edema), bloody sputum (hemoptysis), fatigue, weakness, nausea, vomiting, indigestion, hiccups, sweats (diaphoresis), fever, chills, and muscle pain (myalgia) also are common symptoms.

There are cases of what is called silent myocardial infarction where there is no pain felt by the patient. Often, any other symptom is overlooked because there is no pain. This is often the case if the patient is a diabetic. Painless heart attacks represent as much as 20 percent of all cases.

Testing

Testing is an important part of a heart attack patient's medical care. An electrocardiograph (EKG) measures heart contractions and can show abnormal rhythms and patterns. A single EKG, even if abnormal, is not solely diagnostic. It is much better to have an earlier EKG for comparison. The EKG may show abnormal Q waves, ST segment or T wave abnormalities, abnormal conduction patterns, or abnormal heartbeat.(17) As many as 40 percent of patients who have suffered acute MI do not show diagnostic EKG changes.(18)

Blood tests are also used to diagnose heart attacks. An isoenzyme known as CK/MB is elevated in about 95 percent of patients who have suffered an acute myocardial infarction. It takes about four to eight hours for CK/MB to rise after a heart attack. Therefore, if a patient's chest pain started one hour before a blood test, a normal CK/MB level would not rule out an acute MI, so a series of blood tests should be done. To complicate things further, CK/MB levels will only remain elevated up to 48 to 72 hours after a heart attack.

The levels of blood enzymes known as AST and SGOT also rise after an acute MI, but they are not as reliable as CK/ MB levels. SGOT also rises after liver damage and may rise after kidney or lung damage. Some hospitals do not routinely test AST and SGOT today because other tests are more accurate diagnostic tools. The white blood cell count can also be elevated in severe MI cases.

Treadmill testing can be used as a diagnostic or prognostic tool. Multivessel heart disease or left main coronary artery disease should be suspected if there is an onset of ST depression, or a change in the EKG within the first three minutes of exercise, ST depression that persists after eight minutes of exercise, or ST segment depression that downslopes.

Angiography or coronary arteriography (injection of dye into the coronary vessels) and ventriculography (injection of dye into the left ventricle) should be done only when they can be used to alter the patient's treatment in a favorable way. The results of these tests show the degree of narrowing in various artery segments, the size and quality of vessels beyond the narrowed segments, the presence of collateral circulation, and left ventricular function.

Echocardiography, or ultrasonic study of the heart, is used to evaluate heart function, such as the ratio of the amount of blood pumped with each beat to the amount of blood present immediately before the ventricle contracts (the ejection fraction) and abnormal wall motion. It is also useful in detecting blood clots.

A technetium scan is used to measure ventricular volume (the amount of blood the heart can hold), ejection fraction, and regional ventricular wall motion when the person is at rest and during exercise. It can also identify transient global and regional left ventricular dysfunction. A patient showing decreased ejection fraction with exercise is likely to have severe ischemia or multivessel disease.(19)

A thallium scan, an extremely sensitive test, can be used in addition to exercise stress testing to accurately diagnose heart failure or heart disease. Before the scan, thallium, a radioisotope, is given to assess regional myocardial perfusion or blood supply to each area of the heart. Images are taken immediately after exercise to identify acute ischemia and later to discriminate between reversible ischemia and infarction.(20)

Legal Strategy

The most common form of negligence in coronary medicine is the misdiagnosis of acute heart disease.(21) This can be a failure to diagnose unstable angina or a failure to diagnose the myocardial infarction itself.

Before accepting a case, the lawyer should make sure that the patient suffered profound damage--death, brain damage, or permanent heart damage resulting in a substantially reduced life expectancy or quality of life. If the patient has not suffered profound damage, the cost and risk of litigation will outweigh any benefit to the client.

Of course, existence of damage does not mean that it was proximately caused by medical negligence. The lawyer should be wary of a natural tendency to be swayed by a devastating injury or death. The lawyer needs to analyze whether negligence occurred and whether potential defenses have merit.

Once the case is accepted, those defenses must be addressed before and during trial. Possible defenses include:

* Atypical presentation. The doctor's mistake in diagnosis is justified because of the atypical presentation of the illness. The defense will claim that the patient's signs and symptoms were so unusual that they misled the doctor and would have misled any doctor. Therefore, the doctor's error in judgment was not a deviation from the standard of care.

* Personal responsibility. This defense may be asserted in various ways. The defendant may claim that the patient failed to give an accurate history of risk factors or signs and symptoms and that this misdirected the physician, causing the misdiagnosis. Or the defendant may say that the patient's failure to return to the hospital or doctor's office after the pain became worse prevented a reevaluation of the condition, which would have allowed for a more accurate diagnosis. Or the defense may argue that the patient failed to adhere to the doctor's written or verbal instructions.

* Proximate cause. A delay in diagnosis is not the cause of the patient's injuries or death. The defendant claims that even if a timely diagnosis had been made and all available treatment given, the patient would have had a similar outcome because of the extent and nature of the disease.

* Speculation. The argument is that the jury is being required to speculate about liability or damages because there is insufficient data. This defense is often raised when no EKGs, heart enzyme tests, angiograms, or echocardiograms were done or where there are simply too many unknowns regarding the cause and mechanism of death because no autopsy was done.

* Limitation of future damages. Even when negligence and proximate cause are established with medical probability, the defense may claim that future damages are extremely limited. The argument goes this way: The natural history of the disease was so far along that even with diagnosis and treatment the patient would have had a substantially reduced life expectancy. Also, the patient would have sustained a significant reduction in the ejection fraction or cardiac output capacity of the heart, resulting in a significant cardiac disability. The patient, therefore, would have been incapable of gainful employment even with proper diagnosis and treatment.

Best Weapon

In the case of wrongful death, an autopsy is usually essential to prove that a patient died of the infarct. An autopsy will show the extent of the infarct and the likelihood that proper treatment would have prevented injury or death.

All tissue slides from the autopsy should be reviewed by an independent pathologist, who can often reasonably accurately determine when an infarct occurred. These slides can be duplicated as photographs to be used by the plaintiff as demonstrative evidence.

If an autopsy was not performed, the plaintiff's lawyer must consider advising the family to disinter the body before prosecution of the case. The heart deteriorates at a slower rate than many other organs in the body. It is possible to exhume a body and get valuable information about the heart even two to three years after death.

While it is true that an autopsy can yield negative evidence that is harmful to the case, it is better to know this evidence before accepting a case. Then, the decision to prosecute or not prosecute is an informed one. Without an autopsy, evaluating a patient's treatment is difficult. Did the heart attack destroy the heart's ability to pump, or was damage limited? How many vessels were affected? What was the degree of calcification? Were those vessels bypassable? Were the vessels treatable with angioplasty?

Without an autopsy, the cause of death might be known but the mechanism of death may be unknown. Autopsy is the best weapon against speculation in the wrongful death case.

On the Offense

Proximate cause is often the only real battleground in the case of misdiagnosis of acute coronary disease. No case should be taken until it has been reviewed by medical experts who have confirmed that the patient's injury or death was proximately caused by the defendant's actions.

Testimony regarding the standard of care can often best be provided by doctors of the same specialty as the defendant. An emergency room physician, a board-certified internist, or a family physician testifying on the standard of care makes an excellent match against a defendant in the same specialty. Even though these experts may have opinions on proximate cause that are favorable to your client, separate experts in cardiology and pathology should be used. In some cases, cardiac surgeons should be added as well.

When faced with a cardiac surgeon as an expert on life expectancy, one theme available on cross-examination is the limited amount of time a patient sees a surgeon after the surgery. Cardiologists often care for patients for a lifetime, while surgeons often only provide care until the patient is stabilized after surgery. Thus, the cardiologist has a greater frame of reference from which to predict life expectancy and survivability than does the surgeon.

The underlying questions on proximate cause are: What amount of damage would the patient have sustained if he or she had received appropriate care? What amount of damage did the patient ultimately sustain because of the defendant's misdiagnosis?

Again, it is important to note that infarcts are not point-in-time events but actually occur over hours or days. Once an acute infarct occurs, the heart is highly irritable and at risk for fatal arrhythmias. Proper diagnosis yields preventive measures that help slow the spread of the infarct and prevent an abnormal heartbeat from developing.

Negligence is often the easiest part of the case to prove. Consequently, when cost containment is a factor and the doctor's mistake is obvious, focus on the proximate cause issue because it may prove to be insurmountable.

On the issue of negligence, it is important to prove not only what happened but why it happened. When the why question is answered through detailed discovery, the doctor's negligence often becomes compelling. For example, discovery may show that the patient's cardiac disease was missed because the physician in the emergency room or the urgent care facility was not trained in emergency medicine or generally not experienced in acute care. Or it may show that the physician was a moonlighting resident whose background was in a specialty unlikely to involve the diagnosis of heart attacks or that the doctor was distracted by legal problems, such as other professional negligence suits.

Sometimes, the negligence claim is based on the doctor's failure to obtain a thorough medical history. Were all the risk factors obtained during the history? Who took the history? Was it a registered nurse, a medical assistant, or the physician? Did that person know all the risk factors and types of pain that acute cardiac disease can produce? Did that person think the patient's problem might be heart disease, and did that person ask the patient about the location, extent, and duration of pain?

In middle-aged people with chest pain, cardiac disease should always be high on the list of possible causes of the pain. Cardiac disease must be ruled out because failure to do so may result in the patient's death. The lawyer must find out whether there was sufficient reason to include unstable angina or myocardial infarction within the differential diagnosis and whether these were ruled out.

Failure to take an EKG in a patient with suspected heart pain is a failure to act within the applicable standard of care. However, as stated before, a single EKG may not be diagnostic. The doctor may have been negligent in failing to compare the EKG with previous ones. With fax machines, it is easy for one hospital to obtain an EKG from another hospital for immediate comparison. Subtle changes can often be informative, alerting the doctor to the possibility of myocardial ischemia and requiring appropriate preventive measures to lessen the chance of full-blown infarct or fatal arrhythmia.

The defense will try to separate the patient's signs and symptoms, arguing that independently they are not specific to acute heart disease. For instance, vomiting can be caused by a gastrointestinal problem; fever can be a response to inflammation anywhere in the body; and chest pain can be a result of anxiety, gall bladder disease, esophageal spasm, gastric upset, or pulmonary illness.

However, when the signs and symptoms are considered together and considered along with the patient's risk factors, they may indicate that the doctor should have suspected and diagnosed a heart attack. In a cross-examination of the defendant, it is important to point out how long medical science has known the signs and symptoms of myocardial infarction and unstable angina and in what year of medical school the medical student must master this information.

It is also helpful in cross-examination during discovery deposition to explore the defendant's knowledge of patterns of pain as they relate to certain illnesses by asking hypothetical questions involving a given pain pattern with a given history. The answers may show the defendant's lack of knowledge of not only heart disease but other acute illnesses.

In the final analysis, the plaintiff's lawyer must prove that the client received bad medical care resulting in profound injury to the patient and patient's family. By mastering the medicine, obtaining an autopsy, and using multiple experts, the plaintiff's attorney will increase the probability that justice will prevail.

Notes

(1) HARRISON'S PRINCIPLES OF INTERNAL MEDICINE 953 (Jean D. Wilson et al. eds., 12th ed. 1991). (2) Id. (3) Id. (4) Id. (5) EUGENE BRAUNWALD, HEART DISEASE: A TEXTBOOK OF CARDIOVASCULAR MEDICINE (3d ed. 1988). (6) F. Rovelli et al., Effectiveness of Intravenous Thrombolytic Treatment in Acute Myocardial Infarction, 1986 LANCET 397. (7) J. WILLIS HURST ET AL., THE HEART 1022 (7th ed. 1990). (8) Id. at 1022-23. (9) Id. at 1023. (10)Id. at 1041. (11) Stephen G. Ellis et al., Angiographic and Clinical Predictors of Acute Closure After Native Vessel Coronary Angioplasty, 77 CIRCULATION 372 (1988). (12) HURST, supra note 7, at 1031; BRAUNWALD, supra note 5. (13) HURST, supra note 7, at 1031. (14) Spencer B. King et al., A Randomized Trial Comparing Coronary Angioplasty with Coronary Bypass Surgery, 331 NEW ENG. J. MED. 1044 (1994). (15) James Cameron et al., Outcome Five Years After Percutaneous Transluminal Coronary Angioplasty or Coronary Artery Bypass Grafting for Significant Narrowing Limited to Left Anterior Descending Coronary Artery, 74 AM. J. CARDIOLOGY 544 (1994). (16) HURST, supra note 7, at 131-32. (17) Id. (18) PETER ROSEN ET AL., EMERGENCY MEDICINE CONCEPTS 1321 (3d. ed. 1992). HARRISON'S PRINCIPLES OF INTERNAL MEDICINE, supra note 1, at 966. (19) Id. (20) See generally PHYSICIAN INSURERS ASS'N OF AM., ACUTE MYOCARDIAL INFARCTION STUDY (May 1996).

Richard D. Lawrence is a partner with Richard D. Lawrence (r associates in Cincinnati. Jill Gustafson is an associate with the firm.