Poincaré plot in ischemic rabbit hearts

Heart rate variability can be evaluated by Poincaré plot. Its parameter SD1 describes short-term variability which is mainly caused by respiratory sinus arrhythmia, whereas SD2 describes long-term variability. Ischemia is believed to affect non-autonomic mechanism of the heart and as a result of it also HRV. However not only this mechanism is responsible for HRV changes, because ischemia affects both parameters significantly even in isolated denervated hearts. Both parameters - SD1 and SD2 - show lower values in ischemic phases of experiment than in reperfusion ones. Shape of Poincaré plot´s attractor has a form of line both in ischemic and reperfusion periods; however in reperfusion phases of experiment the attractor is longer.