Obstructive sleep apnea (OSA) is a sleep-disordered breathing condition, which is increasingly being recognized as having wide-ranging pathophysiological effects on multiple organ systems. Although multiple factors affect the incidence and severity of OSA, male sex and obesity seem to play an influential role. The apnea-ventilation cycle, characterized by abnormalities in gas exchange, exaggerated respiratory effort and frequent arousals, has been shown to have deleterious effects on circulatory hemodynamics, the autonomic milieu, hormonal balance, inflammatory and coagulation cascades, endothelial function, and the redox state, with potential cardiovascular significance. Consequently, OSA is being increasingly implicated in a multitude of cardiovascular diseases (CVD) such as hypertension, congestive heart failure, atrial fibrillation, stroke, coronary artery disease, pulmonary hypertension, and metabolic syndrome. The strength of association for individual CVD is varied, and outcomes of clinical studies are conflicting. In addition, obesity, which is closely linked to both OSA and CVD, makes it harder to ascertain the independent role of OSA on CVD. Although available evidence is inconclusive, there is an increasing recognition of the direct role for OSA in CVD. Similarly, although several studies have demonstrated the cardiovascular benefits of OSA treatment, further studies are needed to confirm this.

Takotsubo cardiomyopathy (TC) is characterized by reversible ventricular dysfunction, not limited to the distribution of an epicardial coronary artery. A disease primarily afflicting post-menopausal women, it is frequently mistaken for acute anterior wall myocardial infarction. Alternatively called Stress Cardiomyopathy, physical or emotional triggers are identified in only three fourths of TC patients. Long considered a benign condition, recent findings suggest poor short term prognosis similar to acute coronary syndrome (ACS). Despite the widely recognized pathophysiological role of catecholamine excess, its diagnostic role is uncertain. TC is suspected based on typical wall motion abnormalities in ventriculogram or echocardiogram. Several additional electrocardiographic, laboratory and imaging parameters have been studied with the goal of clinical diagnosis of TC. While several clinical clues differentiate it from ACS, a clinical diagnosis is often elusive leading to avoidable cardiac catheterizations. Natriuretic peptides (NPs), a family of peptide hormones released primarily in response to myocardial stretch, play a significant role in pathophysiology, diagnosis as well as treatment of congestive heart failure. TC with its prominent ventricular dysfunction is associated with a significant elevation of NPs. NPs are elevated in ACS as well but the degree of elevation is typically lesser than in TC. Markers of myocardial injury such as troponin are usually elevated to a higher degree in ACS than in TC. This differential elevation of NPs and markers of myocardial injury may play a role in early clinical recognition of TC.

Coronary artery disease (CAD) in women is an important public health concern. However, the delayed onset of CAD in women and the apparent protective effect of estrogen are partly responsible for the misconception that CAD primarily affects men. Though women share the same traditional risk factors as men, they have some unique risk factors and differences in pathophysiology. Women are more likely to have atypical symptoms, contributing to the under-diagnosis of CAD. Fewer women than men receive pharmacological treatment for CAD on admission but more women receive anxiolytics, antidepressants, and narcotics. Disparities have been found in the administration and performance of both noninvasive testing and cardiac catheterization. The frequent absence of angiographic disease in symptomatic women often leads to searching for a noncardiac etiology for chest pain rather than the recognition of a higher incidence of nonocclusive CAD in women, a concept supported by imaging studies. Observational studies have pointed toward a beneficial effect of hormone replacement therapy (HRT) on CAD, but more recent randomized trials have disputed this and advocate against the use of HRT for CAD prevention. The role of HRT in CAD is still debated. Physicians have to be acutely aware of gender bias and gender-based differences in clinical presentation, accuracy of diagnostic tests, and clinical outcomes.

A PUBMED search was performed for peer-reviewed studies published in English from 2002 through August 2006. Accuracy parameters for detection of obstructive coronary artery disease by MSCT (multislice computed tomography) coronary angiography were analyzed on patient and segment basis. Pooled estimates of sensitivity (SN), specificity, positive predictive value, and negative predictive value (NPV) in patient-based analyses were 93%, 82%, 83%, and 92%, respectively. For 64/40-slice MSCT the respective accuracy estimates were 96%, 91%, 93%, and 96% and were better compared with 16-slice MSCT. Also, more segments were evaluated by 64-slice MSCT (96%) compared with 16-slice MSCT (86%). The SN and NPV of MSCT coronary angiography for patients with low coronary artery calcium (CAC) score were 92% and 99% compared with 77% and 89% for patients with high CAC score. The accuracy estimates for MSCT in studying coronary artery by-pass grafts and intracoronary stents showed a SN and NPV of 97% and 97% for graft occlusion or stenosis and only 71% and 93% respectively for in-stent restenosis. Diagnostic accuracy of MSCT coronary angiography has improved with the newer 64-slice versions. High CAC scores can affect the accuracy of MSCT coronary angiography. Although the accuracy of MSCT in evaluating native vessel and graft disease has improved significantly, its reliability in studying intracoronary stents remains uncertain.

Despite major improvements in the treatment of heart disease, it remains a major source of morbidity and mortality on a global scale. Currently, invasive coronary angiography remains the gold standard for identification of obstructive coronary artery disease. However, recent advances in computerized tomographic (CT) techniques of the heart allow for accurate, non-invasive characterization of atherosclerotic coronary disease and other cardiac abnormalities. The calculation of coronary artery calcium scores with electron beam CT has largely been supplanted by high-resolution CT angiography using multi-slice detectors (MSCT) which can provide detailed multidimensional visualization of cardiac structures. Although evaluation of obstructive coronary disease is the primary use of MSCT, its use in identifying congenital defects, planning thoracic procedures and characterizing cardiac function continues to grow. Accordingly, appropriate incorporation of MSCT/CT angiography into clinical practice continues to be defined. Several limitations to MSCT remain which reduce its accuracy, such as in patients with arrhythmia and in patients with either coronary stents or heavily calcified coronaries. Despite its current limitations, MSCT remains a rapidly advancing field and an increasingly valuable tool for the non-invasive evaluation of cardiac pathology.