Most diagnoses of cardiovascular disease are made in the office or at the bedside. For example, in pulsus alternans of the radial pulse, observed when first greeting a patient, alteration of intensity of the second sound and systolic murmur and a ventricular (S3) gallop are clinical pearls--often subtle--that diagnose cardiac decompensation. A faint gallop, ventricular (S3) or atrial (S4), might be overlooked in a patient who has an emphysematous chest and an increase in anteroposterior diameter if one listens over the usual areas of the precordium. However, the gallop might be detected easily by listening over the xiphoid or epigastric area. How do you tell the difference between an S4, a split first sound, and an ejection sound? The S4 is eliminated with pressure on the stethoscope, but pressure does not eliminate the ejection sound or the splitting of S1. The atrial sound (S4) is most frequently found in patients who have coronary heart disease, and it is a constant finding in patients who have hypertension. It does not denote heart failure, as does the S3 (ventricular) gallop. In some patients, both atrial (S4) and ventricular (S3) diastolic gallops may be present. This occurrence is common in patients with cardiac decompensation associated with coronary heart disease, hypertensive heart disease, and dilated cardiomyopathy. When these diastolic filling sounds occur in close proximity, a short rumbling murmur may be heard, which causes confusion of this sound with that of a valvular or congenital lesion. When both sounds occur exactly simultaneously, a single sound results. Often, this sound is louder than either the first or second sound and can be misinterpreted as either a valvular or congenital lesion. This, however, is a summation gallop, which is rare. For the most accurate timing of heart sounds and murmurs, the simple technique called "inching" is the best. Keeping the second sound in mind as a reference, the physician moves (inches) the stethoscope from the aortic area to the apex. An extra sound may be noted to occur in systole before the second sound, thereby diagnosing a systolic click. If the sound occurs after the second sound, however, it is an S3 or ventricular diastolic gallop. If a murmur appears before S2, it is a systolic murmur; if it appears after S2, it is a diastolic murmur. When the Austin-Flint murmur is heard, significant aortic regurgitation exists.(ABSTRACT TRUNCATED AT 400 WORDS)