About a million Americans die of heart disease every year, about half of them without warning. Many times that number have the unrecognized arterial disease (and some have had unrecognized heart attacks) that can lead to sudden death. That's why UCLA cardiologist Karpman believes that patients should recignize and report the many vaguer symptoms, listed here, that often occur in the absence of chest pain; that everyone should be aware of the risk factors (smoking, high blood pressure, high blood cholesterol, etc.) and take measures to reduce them (diet, exercise, drugs); and that doctors should do more screening for SNI (silent myocardial ischemia), especially in patients with risk factors, using the range of advanced tests he helped to pioneer. Karpman's expert cautionary guidance, while a bit stiff in style, is understandable but not simplistic, justifiably scary without being alarmist; and his recommendations strike a judicious balance between self-help and professional oversight.