Experimental and clinical aspects of total electrocardiographic alternation

Electrical alternans in cardiac tamponade.

“…This electrocardiographic abnormality was initially observed in the laboratory by Herring in 1909 (Brody et al, 1973), and first reported clinically the year after by Lewis (1910). Other early reports were those of Hamburger, Katz, and Saphir (1936) and of Brody and Rossman (1937).…”

“…On the contrary, the present electrocardiographic findings lend support to the theory which presumes exaggerated anatomical motion of the heart within the pericardial sac enlarged by massive effusion. Indeed, several types of such a cardiac motion have been demonstrated in patients with pericardial effusion and total electrical alternans by cineangiography (Price and Dennis, 1969) and echocardiography (Feigenbaum et al, 1966;Usher and Popp, 1972), and by using a laboratory model (Brody et al, 1973). With the last method both oscillatory and twisting cardiac motions with varying frequency, plane, and amplitude were observed.…”

“…The factors which probably determine the frequency and form of the cardiac motion and hence the appearance of electrical alternans are the heart rate, the pericardial pressure, the rate of accumulation, volume, and viscosity of the pericardial fluid, an aortic root fixed by secondary deposits, the rigidity and configuration of the pericardial sac, and the mobility of the pendulumlike heart within the pericardial sac (Usher and Popp, 1972;Brody et al, 1973). A combination of at least three factors is probably necessary to produce the type of heart motion that is associated with electrical alternans, since the presence of two of them (Tables I and II) did not produce alternans in the effusion group of patients.…”

“…Finally, all main complexes (P-QRS-T) may alternate simultaneously when the phenomenon is called total electrical alternans (Littmann and Spodick, 1958;Brody et al, 1973). Although ventricular and total electrical alternans are not very common they are of clinical interest because they occur primarily in association with massive pericardial effusion and cardiac tamponade (McGregor and Baskind, 1955;Colvin, 1958;Littmann and Spodick, 1958;Spodick, 1962;Bashour and Cochran, 1963;Lawrence and Cronin, 1963;Gabor, Winsberg, and Bloom, 1971;Usher and Popp, 1972;Brody et al, 1973).…”

“…One attributes the alternation of the electrocardiographic complexes to alternating conduction within the myocardium (Spodick, 1962). The other maintains that the conduction within the myocardium during alternans remains unchanged, but that a cyclic motion of the heart within the distended pericardial sac accounts for the alternating electrocardiographic pattern (Feigenbaum, Zaky, and Grabhorn, 1966;Price and Dennis, 1969;Usher and Popp, 1972;Brody et al, 1973). It is the purpose of this paper to report the clinical, radiological, and electrocardiographic findings in patients with pericardial effusion and tamponade associated with total and ventricular electrical alternans, in whom the confirmation of the mechanical theory of the genesis of alternans is based on electrocardiographic data.…”