With high heart rates, in this case 120 BPM, the diastolic interval is shortened. Accordingly, S3 and S4 sounds begin to merge, producing a single loud heart sound.
The cardiac animation video presents an enlarged left ventricle with decreased left ventricular contractility and a minimally enlarged left atrium.
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The patient's position is supine.
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The cardiac animation shows an enlarged left ventricle with decreased left ventricular contractility and a minimally enlarged left atrium.