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Figure 12 | Cardiovascular Ultrasound

Figure 12

From: Cardiac reflections and natural vibrations: Force-frequency relation recording system in the stress echo lab

Figure 12

Telemonitoring in coronary artery disease. An intermediate situation between normal and chronic failing hearts is effort induced ischemia, in which the normal up sloping force-frequency relation is abruptly interrupted by the hypoxic dysfunction in calcium homeostasis, resulting in reduced contractile performance at ischemia. In this scenario a three-dimensional diagram could be determined in which for each heart rate not only indicates the instantaneous force value but also enables the variation of said value with time to be monitored. With patient sleeping (grey FFR curves) range of frequencies of the FFR are reduced and the slope of the relation flattened do to the reduced catecholamine spillover. During daily activities, the range of frequencies of the FFR are expanded and the slope of the relation steeper. At higher heart rates induced ischemia (red symbols), immediate blunting of the FFR occurs and a sudden descending limb begins.

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