A 55-year-old woman with metastatic lung cancer presents with dyspnea and pedal edema. On examination, the JVP is at 10 cm, with a negative Kussmaul's sign. The heart sounds are diminished and the lungs have bibasilar crackles. The ECG shows QRS complexes of variable height.For the patient with SOB and peripheral edema, select the most likely diagnosis.
Electrical alternans (a beat-to-beat alternation in one or more component of the ECG signal) can occur in pericardial effusion and numerous other conditions. Total electrical alternans (P-QRS-T) and sinus tachycardia is relatively specific for pericardial effusion (often with tamponade).
cardiac tamponade
constrictive pericarditis
restrictive cardiomyopathy
right ventricle myocardial infarction (RVMI)
C.V.S.