Screening of Ischemic Heart Disease based on PPG Signals using Machine Learning Techniques.

The increasing rate of cardiac ailments has led to the rise in the scrutinization of ones cardiac health. The prevalent techniques for detecting heart diseases are costly and require expert supervision as well as modern equipment. Thus there is a need for an alternative low cost and easily available technique. Finger-tip photoplethysmography (PPG) signals can be used for identifying Ischemic Heart Disease (IHD). This technique of screening the disease will be very helpful to the inhabitants of remote, underdeveloped and unprivileged areas. Time-domain analysis of the signal was done for extracting different features. Segregation of diseased and healthy subjects was performed using Decision Trees, Discriminant Analysis, Logistic Regression, Support Vector Machine, KNN, and Boosted trees. Ten different performance metrics was studied using the confusion matrix. After analysis, the accuracy, sensitivity, specificity, and precision of 0.94, 0.95, 0.95 and 0.97 respectively was obtained using Boosted tress classifier. ROC and AUC were calculated to establish the robustness of the classification methods for determining IHD patients.

Estimation of echocardiogram parameters with the aid of impedance cardiography and artificial neural networks.

The advent of cardiovascular diseases as a disease of mass catastrophy, in recent years is alarming. It is expected to spread as an epidemic by 2030. Present methods of determining the health of one's heart include doppler based echocardiogram, MDCT (Multi Detector Computed Tomography), among various other invasive and non-invasive hemodynamic monitoring techniques. These methods require expert supervision and costly clinical set-ups, and cannot be employed by a common individual to perform a self diagnosis of one's cardiac health, unassisted. In this work, the authors propose a novel methodology using impedance cardiography (ICG), for the determination of a person's cardio-vascular health. The recorded ICG signal helps in extraction of features which are used for estimating parameters for cardiac health monitoring. The proposed methodology with the aid of artificial neural network is able to determine Stroke Volume (SV), Left Ventricular End Systolic Volume (LVESV), Left Ventricular End Diastolic Volume (LVEDV), Left Ventricular Ejection Fraction (LVEF), Iso Volumetric Contraction Time (IVCT), Iso Volumetric Relaxation Time (IVRT), Left Ventricular Ejection Time (LVET), Total Systolic Time (TST), Total Diastolic Time (TDT), and Myocardial Performance Index (MPI), with error margins of ±8.9%, ±3.8%, ±1.4%, ±7.8%, ±16.0%, ±9.0%, ±9.7%, ±6.9%, ±6.2%, and ±0.9%, respectively. The proposed methodology could be used in screening of precursors to cardiac ailments, and to keep a check on the cardio-vascular health.

Stroke Volume, Ejection Fraction and Cardiac Health Monitoring using Impedance Cardiography.

In recent years occurrence of cardiac ailments have seen an exponential rise. In view of this it is highly important to monitor one's cardiac health. Currently employed methods for cardiac health monitoring are costly, require expert supervision and are available only at central hospitals. In order to overcome these obstacles, we have proposed a novel, non-invasive, cardiac health monitoring mechanism based on Impedance Cardiography (ICG). In this work we have proposed a methodolgy for determination of stroke volume (SV), left ventricular ejection fraction (LVEF), left ventricular end systolic volume (LVESV), and iso-volumetric relaxation time (IVRT), based on ICG. The proposed models report $\mathrm{r}^{2}$ values of 0.86, 0.97, 0.99, and 0.96 for SV, LVESV, LVEF, and IVRT, respectively. The proposed methodology also provides us an insight into the use of ICG for cardiac health monitoring, and diagnosis of critical cardiac ailments.

Impact of angiographic & procedural factors on the treatment of ostial LAD or LC(x) disease.

AIMS & OBJECTIVES: This study was designed to evaluate the impact of angiographic & procedural factors on MACE after DES deployment in ostial lesions of LAD & LC(x). PATIENTS, MATERIALS & METHODS: 65 patients with ostial disease of LAD or LC(x) underwent PCI using DES. In 56 patients the stent was placed perfectly at the ostium & in 9 patients the LMCA was covered as per protocol. Angiographically 48 patients had a bifurcation angle > 70 degrees whereas in 17 patients the angle was < 70 degrees. RESULT & ANALYSIS: Multivariate Regression Analysis was done. Mean age was 59 years & 77% were male patients. 69% were hypertensives & 52% diabetics. LAD was treated in 88%. 74% had bifurcation angle > 70 degrees. 26% presented with an angle < 70 degrees LMCA was covered during stent implantation in 12% of cases. Average follow up was 1.5 +/- 0.8 years. Overall MACE was 12%. Bifurcation angle > 70 degrees & use of Cypher stent remained significant in reduction of MACE (P < 0.05). Using Univariate analysis of 2 sample sets like cases with angle of separation > 70 degrees (n = 48) & with angle less than < 70 degrees (n = 17), it was found that covering LMCA was beneficial in cases with angle of separation < 70 degres (p-value and correlation coefficient nearer to statistical significance). CONCLUSION: Angiographic factors like bifurcation angle is important to formulate the strategy of stenting procedure in the ostial disease of LAD or LC(x) even with DES.

Importance of ischaemic time as a predictor of LV systolic function in Indians.

OBJECTIVE: Sucessful reperfusion therapy in AMI improves LV systolic function. Success in thrombolytic therapy is directly related to the ischaemic time. Our aim in the present study was to observe the importance of ischaemic time as a predictor of left ventricular systolic function in patients undergoing PPCI. In addition, the contribution of presentation delay in determining the ischaemic time in the Indian scenario was also observed. MATERIALS & METHODS: The present pilot study was carried out on 48 Indian patients (Male-40) of STEMI (Killip class I & II) undergoing primary PCI in last 2 yrs. Suggestive chest pain, ECG evidence of STEMI coming within 12 hrs were the inclusion criteria. Patients coming after 12 hours without ongoing chest pain, Killip class III & IV, the patients who were thrombolysed outside and the patients with prior PCland/or CABG were excluded from the study. Cardiac echodoppler study was done in every patient during followup at one month.Every patient received pre and peri procedural abciximab infusion and thrombosuction was done in all before deployment of BMS during the transfemoral primary PCI. RESULTS: Data analysis revealed mean age was 57.6 yrs, male preponderance (80%),diabetes (35%),hypertension (61%), Smoking (61%), average total ischaemic time 7.6 +/- 3.78 hours, average presentation delay 6.26 +/- 3.77 hrs, average door to balloon time 60 +/- 14 mins, SVD (69%), LAD involvement(60%). Multivariate regression analysis without considering any other factor showed predicted LV Systolic function one month post PPCI to be 74.08%. Mean LVEF: 58.2%. Most interesting observation is 0.63% reduction of predicted LVEF for each hour increment of ischaemic time. Also LAD occlusion is associated with 4.91% reduction of predicted LVEF compared to other vessel(s) involvement. All the 48 patients who underwent PPCI not only survived but also had good LV Systolic function one month post PPCI. CONCLUSION: Ischaemic time is an important predictor of LV Systolic function even after PPCI. lncrease in ischaemic time by one hour reduces predicted LVEF by 0.63%.Presentation delay is mostly responsible for total ischaemic time in India.

Thrombosuction with export aspiration catheter during PCI in acute MI.

The angiographic demonstration of thrombus laden LAD in a ventilated young man with IABP (to combat cardiogenic shock) demanded thrombosuction. Following thrombosuction no significant lesion was visible that could have mandated PTCA-Stenting. Follow-up coronary angiography in this hyperhomocysteinaemic young subject after one and a half month revealed normal coronaries. Thrombosuction alone unaccompanied by any other additional intervention is infrequently reported.