Coronary Heart Disease (CHD) refers to atherosclerosis of the arteries that supply the heart muscle. Insufficiency of blood supply may result from a reduction of blood flow through one or more of these arteries. Heart cells are dependent on blood flow through these arteries to provide oxygen and to carry away metabolic products. Without an adequate flow of blood, these cells can become injured or die. When this occurs, immediate emergency treatment is necessary to stop the injury from widening, killing additional heart cells, and increasing the risk of complications or death.
Epidemiology of IHD in the United States CHD caused 1 out of 5 deaths in the United States in 2004. Sixteen million individuals within the United States have coronary heart disease and approximately one million individuals experience a coronary event each year. As the number one killer of Americans, coronary heart disease claims the lives of 500,000 individuals each year. While an estimated 650,000 Americans will experience an acute heart attack this year, only 50% of patients with myocardial infarction have a prior history of coronary artery disease (CAD).
Approximately 65% of all heart attacks and 85% of all CHD deaths occur to people aged 65 or older. CHD is the leading cause of death for people over 65 years of age and the second leading cause of disability. Throughout life, men have a much higher death rate from CHD than do women. CHD risk increases with age. Major increases in the occurrence of heart disease begin for men at the age of 35. Women begin to display a marked increase after menopause. CHD death rates are higher among blacks than whites until advanced age. In 2008, CHD death rates were 194.2 per 100,000 for white males and 223.9 per thousand for black males. Black females have a death rate 29% higher than white females, and in ages under 75, the black female death rate from CHD is more than 71% higher than that of white women. CHD incidence and mortality rates go up as socioeconomic status goes down. Historically, the greatest reductions in death rates have occurred for the highest levels of income and education and among workers in white-collar jobs. Although its role is incompletely understood, family history can contribute to premature heart disease. Evidence seems to indicate that family history can predispose a person to premature CHD through a combination of genetics and a tendency for high levels of risk factors (e.g., smoking, poor diet) to cluster within families.
Cost to the health system The economic impact on the health system grows larger as the population ages. In 2008, the estimated cost of health care expenditures and lost productivity attributable to cardiovascular diseases was $448.5 billion. $156.4 billion of it is attributable to CHD cost alone.(Data based on ‘Heart Disease and Stroke Statistics – 2008 update’ by the American Heart Association). In this respect, incorporating the HyperQ™ stress test into the routine diagnosis and management of CHD patients could potentially have significant economic benefits. See White Paper 4 for details.
Diagnosis Exercise treadmill testing (ETT), in which the electrocardiogram (ECG) is examined during exercise and recovery, is considered the initial diagnostic evaluation of choice for CHD, with over six million exercise tests performed annually in the US. The advantages of this modality are the associated low cost, wide availability and lack of radiation concerns. However, numerous studies show that the diagnostic performance of ETT in detecting CHD is limited, particularly in women.
Other available diagnostic modalities include stress echocardiography, stress SPECT perfusion imaging, CT angiography and invasive angiography. All these techniques are more accurate than ETT, yet they are costlier and involve exposure to significant levels of radiation.
There is thus a clear public health need for an accurate, lowcost, simple to operate and non-radiating technology for the initial detection of CHD with greater predictive value than the current ETT using ST segment analysis.
The HyperQ™ System provides a novel, non-invasive and highly reliable solution for the diagnosis and monitoring of Ischemic Heart Disease. Using proprietary signal processing technology, the system performs analysis of the high-frequency QRS components giving more sensitive and accurate results than conventional stress testing.