PATTERNS OF SPIRAL TIP MOTION IN CARDIAC TISSUES

In support of the spiral wave theory of reentry, simulation studies an d animal models have been utilized to show various patterns of spiral wave tip motion such as meandering and drifting. However, the demonstr ation of these or any other patterns in cardiac tissues have been limi ted. Whether such patterns of spiral tip motion are commonly observed in fibrillating cardiac tissues is unknown, and whether such patterns form the basis of ventricular tachycardia or fibrillation remain debat able. Using a computerized dynamic activation display, 108 episodes of atrial and ventricular tachycardia and fibrillation in isolated and i ntact canine cardiac tissues, as well as in vitro swine and myopathic human cardiac tissues, were analyzed for patterns of nonstationary, sp iral wave tip motion. Among them, 46 episodes were from normal animal myocardium without pharmacological perturbations, 50 samples were from normal animal myocardium, either treated with drugs or had chemical a blation of the subendocardium, and 12 samples were from diseased human hearts. Among the total episodes, 11 of them had obvious nonstationar y spiral tip motion with a life span of >2 cycles and with consecutive reentrant paths distinct from each other. Four patterns were observed : (1) meandering with an inward petal flower in 2; (2) meandering with outward petals in 5; (3) irregularly concentric in 3 (core moving abo ut a common center); and (4) drift in 1 (linear core movement). The li fe span of a single nonstationary spiral wave lasted no more than 7 co mplete cycles with a mean of 4.6+/-4.3, and a median of 4.5 cycles in our samples. Conclusion: (1) Patently evident nonstationary spiral wav es with long life spans were uncommon in our sample of mostly normal c ardiac tissues, thus making a single meandering spiral wave an unlikel y major mechanism of fibrillation in normal ventricular myocardium. (2 ) A tendency toward four patterns of nonstationary spiral tip motion w as observed. (C) 1998 American Institute of Physics.