BACKGROUND: Several different patterns of wavebreak have been described by mapping of the tissue surface during fibrillation. However, it is not clear whether these surface patterns are caused by multiple distinct mechanisms or by a single mechanism. METHODS: To determine the mechanism by which wavebreaks are generated during ventricular fibrillation, we conducted optical mapping studies and single cell transmembrane potential recording in 6 isolated swine right ventricles. RESULTS: Among 763 episodes of wavebreak (0.75 times/sec/cm2), optical maps showed 3 patterns: 80% due to a wavefront encountering the refractory waveback of another wave, 11.5% due to wavefronts passing perpendicularly each other and 8.5% due to a new (target) wave arising just beyond the refractory tail of a previous wave. Computer simulations of scroll waves in 3-D tissue showed that these surface patterns could be attributed to two fundamental mechanisms: head-to-tail interactions and filament break. CONCLUSION: We conclude that during sustained ventricular fibrillation in swine RV, surface patterns of wavebreak are produced by two fundamental mechanisms: head-to-tail interaction between waves and filament break.
Computer Simulation ; Heart Ventricles* ; Membrane Potentials ; Swine* ; Ventricular Fibrillation*

Heart failure refers to a group of clinical syndromes caused by structural or functional abnormalities of the heart that lead to impaired ejection or filling of the ventricles. The traditional Chinese medicine （TCM） theory of cardiac and renal coordination holds that the kidney governs water and plays a key role in maintaining the balance of fluid metabolism. Therefore， the treatment of water retention in heart failure can start from the heart and kidney. The basic pathogenesis of heart failure is kidney deficiency， blood stasis， and water stagnation， and the therapies including dredging the heart and kidneys， warming yang and excreting water， tonifying kidneys and activating blood， and dredging meridians and collaterals. Aquaporins （AQPs）， the key molecular basis of water metabolism， are involved in the pathogenesis of water retention in heart failure together with the arginine vasopressin system （AVP）， renin-angiotensin-aldosterone system （RAAS）， and diuretic resistance. Studies have shown that herbal medicines that regulate the heart and kidney can alleviate water retention in heart failure by targeting AQPs， thereby delaying or even reversing the progression of heart failure. This paper expounds the TCM name and pathogenesis of heart failure from the theory of cardiac and renal coordination， the role of AQPs in the pathogenesis of water retention in heart failure， and the modern connotation of the therapy of tonifying heart and kidney for heart failure， aiming to provide ideas for the prevention and treatment of water retention in heart failure by TCM.