The modeling of the broad-band fluctuation of HRV is given using bounded cascade. The model characteristics are summarized and results from simulating multifractal HRV in health and in autonomic blockade are given. The cascade paradigm raises the question of the role of feedback which functions on the basis of additive law. A dynamic cascade model is given to show how the merge of additive law from feedback with cascade can be made based on a global-cascade-local-feedback framework. Finally, we show experimental evidence of discrete scale invariance in RRi data to support cascade HRV.