Total electrical alternans in ECG along with sinus tachycardia is a specific sign of-

Total electrical alternans in ECG along with sinus tachycardia is a specific sign of cardiac tamponade Cardiac tamponade results from an accumulation of pericardial fluid under pressure, leading to impaired cardiac filling and haemodynamic compromise. Findings during physical examination are included in Beck's triad (sinus tachycardia, elevated jugular venous pressure, low blood pressure) and pulsus paradoxus This may even lead to compression of the ventricles during diastole; cardiac tamponade occurs if excess pericardial fluid causes hemodynamic effects. Electrical alternans - i.e the beat-to-beat variation i electrical amplitude - is the ECG hallmark of cardiac tamponade. Ref Davidson 23rd edition pg 432