Acute coronary syndromes that present without chest pain are commonly undiagnosed or undertreated at hospitals, often resulting in higher fatality rates for these patients, according to an article in the August issue of CHEST. The Australian study suggests that cardiac patients who do not have chest pain may have three times the death rate of other cardiac patients and are less likely to receive medications to slow the progression of an acute myocardial infarction.

“While the majority of people who have acute coronary syndromes, such as heart attacks and unstable angina, feel chest pain, some do not, but, instead, may experience atypical symptoms of fainting, shortness of breath, excessive sweating, or nausea and vomiting” said the study’s lead author, David Brieger, MBBS, PhD. “Other than excessive sweating, each of the dominant symptoms of a heart attack not accompanied by chest pain independently identifies a population that is at increased risk of dying.”

A group of international researchers analyzed data from the Global Registry of Acute Coronary Events (GRACE), a registry of 20,881 patients from 14 countries, including the United States, Canada, Australia, Great Britain, and France. Patients were hospitalized with a variety of cardiac conditions from July 1999 to June 2002.

Of the 1,763 cardiac patients who did not experience chest pain, 13 percent died in the hospital compared with 4.3 percent of those with chest pain. In addition, 23.8 percent of patients without chest pain were initially misdiagnosed when they arrived at the hospital, compared with only 2.4 percent of heart patients who experienced typical symptoms.

Patients without chest pain tended to be older women and to have a history of diabetes, heart failure, or hypertension, as opposed to patients with chest pain who were more likely to be smokers with known plaque in their coronary arteries. Patients with atypical symptoms were also more likely to have the unfavorable outcomes of heart failure, cardiogenic shock, arrhythmias, and renal failure.

“Often, when a patient arrives at the hospital without chest pain, it is only after blood test results come back or other diagnoses are excluded that the physician reassesses the situation and determines it is an acute cardiac event after all,” said Brieger. “We hope that our findings will remind physicians that these events do occur in the absence of chest pain and will prompt them to make the diagnoses and institute the appropriate treatment more rapidly.”

Researchers also discovered that patients who did not experience chest pain were often not given proper medication or offered appropriate cardiac medical procedures. Drugs such as aspirin and beta-blockers are usually given to patients with possible cardiac events when they arrive at the hospital, yet patients who did not have chest pain were significantly less likely to receive these drugs both during their first 24 hours of hospitalization and throughout their hospital stay. These patients were also less likely to undergo procedures such as coronary angiography and percutaneous coronary intervention and were less likely to receive statins at hospital discharge.

“The current gap in treatment and hospital outcomes for patients with atypical symptoms is a problem that needs to be rectified,” said Richard S. Irwin, MD, FCCP, President of the American College of Chest Physicians. “More emphasis needs to be given to identifying and properly treating heart attacks in patients who do not exhibit typical symptoms.”