Substantial understanding has evolved regarding the epidemiology and clinical course of HCM, as well as novel treatment strategies that may alter its natural history. An appreciation that HCM, although an important cause of death and disability at all ages, does not invariably convey ominous prognosis and is compatible with normal longevity should dictate a large measure of reassurance for many patients.

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Abstract-Classifications of heart muscle diseases have proved to be exceedingly complex and in many respects contradictory. Indeed, the precise language used to describe these diseases is profoundly important. A new contemporary and rigorous classification of cardiomyopathies (with definitions) is proposed here. This reference document affords an important framework and measure of clarity to this heterogeneous group of diseases. Of particular note, the present classification scheme recognizes the rapid evolution of molecular genetics in cardiology, as well as the introduction of several recently described diseases, and is unique in that it incorporates ion channelopathies as a primary cardiomyopathy.

In patients with hypertrophic cardiomyopathy, left ventricular outflow tract obstruction at rest is a strong, independent predictor of progression to severe symptoms of heart failure and of death.

Background-A clinical entity characterized by acute but rapidly reversible left ventricular (LV) systolic dysfunction and triggered by psychological stress is emerging, with reports largely confined to Japan. Methods and Results-Over a 32-month period, 22 consecutive patients with this novel cardiomyopathy were prospectively identified within a community-based practice in the Minneapolis-St. Paul, Minn, area. All patients were women aged 32 to 89 years old (mean 65Ϯ13 years); 21 (96%) were Ն50 years of age. The syndrome is characterized by (1) acute substernal chest pain with ST-segment elevation and/or T-wave inversion; (2) absence of significant coronary arterial narrowing by angiography; (3) systolic dysfunction (ejection fraction 29Ϯ9%), with abnormal wall motion of the mid and distal LV, ie, "apical ballooning"; and (4) profound psychological stress (eg, death of relatives, domestic abuse, arguments, catastrophic medical diagnoses, devastating financial or gambling losses) immediately preceding and triggering the cardiac events. A significant proportion of patients (37%) had hemodynamic compromise and required vasopressor agents and intra-aortic balloon counterpulsation. Each patient survived with normalized ejection fraction (63Ϯ6%; PϽ0.001) and rapid restoration to previous functional cardiovascular status within 6Ϯ3 days. In 95%, MRI identified diffusely distributed segmental wall-motion abnormalities that encompassed LV myocardium in multiple coronary arterial vascular territories. Conclusions-A reversible cardiomyopathy triggered by psychologically stressful events occurs in older women and may mimic evolving acute myocardial infarction or coronary syndrome. This condition is characterized by a distinctive form of systolic dysfunction that predominantly affects the distal LV chamber and a favorable outcome with appropriate medical therapy.

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With regard to congenital coronary artery anomalies of wrong aortic sinus origin in young competitive athletes, 1) standard testing with ECG under resting or exercise conditions is unlikely to provide clinical evidence of myocardial ischemia and would not be reliable as screening tests in large athletic populations, 2) premonitory cardiac symptoms not uncommonly occurred shortly before sudden death (typically associated with anomalous left main coronary artery), suggesting that a history of exertional syncope or chest pain requires exclusion of this anomaly. These observations have important implications for the preparticipation screening of competitive athletes.

Mutations in the gene encoding the homeobox transcription factor NKX2-5 were found to cause nonsyndromic, human congenital heart disease. A dominant disease locus associated with cardiac malformations and atrioventricular conduction abnormalities was mapped to chromosome 5q35, where NKX2-5, a Drosophila tinman homolog, is located. Three different NKX2-5 mutations were identified. Two are predicted to impair binding of NKX2-5 to target DNA, resulting in haploinsufficiency, and a third potentially augments target-DNA binding. These data indicate that NKX2-5 is important for regulation of septation during cardiac morphogenesis and for maturation and maintenance of atrioventricular node function throughout life.