**11. Biomedical engineering concept of Heart Failure**

872 Biomedical Science, Engineering and Technology

**d1 d2** 

Fig. 11. (d,e) Patient TURN: (a) Superimposed sequential diastolic snd systolic endocardial frames(whose aortic valves centresand the long axis are matched) before (1) and after (2) administration of nitroglycerin. (b)Instantaneous intra-LV distributions of velocity during diastole, before (1) and after (2) administration of nitroglycerin. (c) Instantaneous LV distributions of velocity during ejection phase, before (1)and after (2) administration of nitroglycerin. (d) Instantaneous intra-LV distributions of pressure-differentials during diastole, before (1) and after (2) administration of nitroglycerin. (e) Instantaneous intra-LV

distributions (pressure-differential) during ejection phase, before (1) and after (2)

administration of nitroglycerin.

Heart Failure, in biomedical engineering (BME) terms, can imply failure of the heart to:


So the factors causing systolic heart failure may be summarized to be:


Now the resultant *dV/dt* factor in item 2 is incorporated in the formula for CCI (equation 3). No doubt, the *PMI* affects *CCI*, but there is no direct formulation connecting these two indices. So we can state that *PMI* and *CCI* are the two parameters that can be attributed to the occurrence of heart failure.

We can then define the Systolic Heart Failure index, as

$$\text{HFIN} = \text{PMI}\left(\text{in }\% \right) \times \text{HR}\left(\text{in }\text{s}^{-1} \right) / \text{CCI}\left(\text{in }\text{s}^{-1} \right) \tag{46}$$

Now, in order to assess the terminal value of *HFIN*, we need to determine the terminal values of *PMI*, *CCI*, and *HR*, by studying normal subjects (as these indices are noninvasively determinable) as well as patients in different stages of heart failure.

Now, based on our studies (in Refs 4 & 5), let us (for the time being) adopt (i) the minimum acceptable value of *CCI* to be 3 s-1, (ii) the maximum acceptable value of *PMI* to be 15 %, and (iii) the maximum resting *HR* to be 120/min or 2 s-1. Substituting these values into equation (46) gives the terminal value of *HFIN* to be 10. In other words, if the value of *HFIN* exceeds the value 10, we can designate the patient to be in heart failure.

### **12. Concluding remarks**

In this chapter, we have developed and presented noninvasive medical tests methodologies and associated NDPI(s), to make the case for reliable medical assessment of organ performance, physiological system function and dysfunction, anatomical structural property and pathology. The following tests and associated NDPI(s) have been presented:


*Together these tests and their associated NDPI (s) can provide more reliable medical assessment. What now needs to be done is (i) application of these tests to large patient populations, and (ii) determination of the ranges of NDPI (s) for normal and abnormal states of organs, physiological systems and anatomical structures.* 

*All of these tests can be employed in tertiary patient case, through the department of biomedical engineering (BME) in a tertiary-cave medical center. This makes a strong case for the institution of BME departments in tertiary case medical centers, which will revolution therapy health care.* 
