Hemodynamic monitoring can reflect cardiac function and blood perfusion and is an indispensable monitoring method in clinical practice. Invasive hemodynamic monitoring methods represented by the thermodilution method are limited in their clinical application scope because they require vascular cannulation. Non-invasive hemodynamic monitoring has attracted extensive attention from medical companies and clinicians at home and abroad in recent years due to its advantages such as safety, non-invasiveness, continuous monitoring, simple operation, and low cost. This paper designs a non-invasive hemodynamic monitoring system based on the impedance cardiography, including hardware, algorithm, software design, and performance parameter evaluation. Among them, the hardware part mainly includes a differential high-frequency constant current source stimulation circuit, impedance cardiogram signal acquisition, and ECG signal acquisition circuit. Signal processing includes wave filtering, impedance cardiogram signal calibration, and ECG signal and impedance cardiogram signal feature point recognition. According to the collected impedance cardiogram and ECG signals, hemodynamic parameters such as heart rate (HR), stroke volume (SV), cardiac output (CO), stroke index (SI), cardiac index (CI), and cardiac contractility index (ICON) are calculated based on the Nyboer thoracic cylinder model. After testing, the key technical indicators of the system hardware are better than that of the relevant medical device standards. The system was used to collect impedance cardiogram and ECG signal data from 40 volunteers. The calculated HR, SV, and CO, three important hemodynamic indicators, were compared with the ICONCore non-invasive cardiac output monitor of OSYPKA Medical in Germany. Their Pearson correlation coefficients were 0.992 ( P<0.001), 0.948 ( P<0.001), and 0.933 ( P<0.001), respectively, verifying that the designed system has high accuracy and reliability.
Cardiography, Impedance/methods* ; Humans ; Hemodynamic Monitoring/methods* ; Equipment Design ; Signal Processing, Computer-Assisted ; Hemodynamics ; Algorithms ; Monitoring, Physiologic/methods* ; Electrocardiography

Artificial Intelligence ; Hemodynamic Monitoring

Artificial Intelligence ; Hemodynamic Monitoring

BACKGROUND: Has been reported that patients exhibiting prolonged paced QRS duration tend to have more serious heart disease, and the paced QRS duration can be an effective indicator of impaired left ventricular function. However, the acute and chronic hemodynamic effects of paced QRS duration and pacing sites during right ventricular (RV) pacing remain unknown. METHODS: A total of 14 patients who underwent electrophysiologic study for paroxysmal supraventricular tachycardia were examined. RV pacing was performed at 10 different sites with cycle lengths of 600 ms and 500 ms utilizing a 6-7F deflectable quadripolar electrode catheter. Systolic, diastolic, and mean blood pressures during pacing were measured once the blood pressure was stabilized. RESULTS: During RV pacing, blood pressures (systolic/diastolic/mean) decreased. The change of post-pacing QRS duration and pre-pacing the systolic blood pressure (SBP) were greater in the group with paced QRS duration. The differences overall were greater than 140 ms. The SBP decrease during pacing was larger in the group exhibiting paced QRS duration of greater than 140 ms. The SBP decrease during pacing showed relation to QRS duration during pacing (r=0.500, p=0.001), the change of QRS duration post-pacing (r=0.426, p=0.001), and SBP during sinus rhythm (r=0.342, p=0.001) on linear correlation analysis. The pacing site, on the other hand, did not affect acute hemodynamic changes during pacing. CONCLUSION: Ventricular pacing of less than 40 ms at the area of paced QRS duration is recommended.
Blood Pressure/physiology ; *Cardiac Pacing, Artificial ; Electrophysiologic Techniques, Cardiac ; Female ; Heart Ventricles/*physiopathology ; Hemodynamic Processes/*physiology ; Humans ; Male ; Middle Aged ; Tachycardia, Supraventricular/physiopathology/*therapy

This study was designed to obtain new parameters representing left ventricular (LV) function independent of irregular RR intervals in atrial fibrillation (AF). AF patients were divided into Normal (n=9) and LV Dysfunction (n=9) groups. The relations between LV outflow peak ejection velocity (Vpe) and preceding (RR-1) or prepreceding RR intervals (RR-2) were obtained using logarithmic equations, from which the squared correlation coefficient (r2), slope, Vpe at RR-1 or RR-2=1 sec (Vpe-1), and the ratio of slope to Vpe-1 (Slope/Vpe-1) were calculated. Among the parameters between RR-1 and Vpe, Slope/Vpe-1 was higher in LV Dysfunction group than in Normal group (p=0.05). When only coordinates with RR-1 from 0.6 to 1 sec were included, Slope/Vpe-1 (p=0.001) was higher in LV Dysfunction group than in Normal group. Among the parameters between RR-2 and Vpe, Slope/Vpe-1, slope, and r2 were different between the two groups. In multivariate analysis, Slope/Vpe-1 between RR-2 and Vpe was only independent parameter. However, Slope/Vpe-1 between RR-1 and Vpe in the coordinates with RR-1 from 0.6 to 1 sec had the highest discriminating power. New parameters derived from the relations between RR intervals and LV performance might be useful to evaluate LV function quantitatively in AF.
Age Factors ; Aged ; Atrial Fibrillation/*metabolism ; Atrial Function, Left ; Echocardiography ; Echocardiography, Doppler, Pulsed ; Electrocardiography ; Female ; Heart/physiology ; Heart Ventricles ; Hemodynamic Processes ; Humans ; Male ; Middle Aged ; Models, Theoretical ; Multivariate Analysis ; Myocardial Contraction ; Myocardium/pathology ; Time Factors ; *Ventricular Function, Left

PURPOSE: We investigated hemodynamic changes in the ophthalmic artery (OA) using color Doppler imaging (CDI) after two horizontal rectus muscles surgery. METHODS: Eyes of the surgical group (n=18) underwent surgery on two horizontal rectus muscles, and the control group was the contralateral eyes. CDI of the OA was performed before operation and on postoperative days (POD) 1, 7 and 30. Peak systolic (Vmax), end diastolic (Vmin), and mean (Vmean) blood flow velocities were measured, and resistivity index (RI) and pulsatility index (PI) were calculated. RESULTS: Vmax, Vmin and Vmean were significantly higher, and RI and PI were significantly lower in the surgical group than in the control group on POD 1 (p< 0.05). In the surgical group, Vmax, Vmin and Vmean were significantly higher, and RI and PI were significantly lower, on POD 1 than those mesured on other days (p< 0.05). CONCLUSIONS: We showed that surgery on the two horizontal rectus muscles increased OA blood flow during the early postoperative period.
*Ultrasonography, Doppler, Color ; Strabismus/*physiopathology/*surgery/ultrasonography ; Postoperative Period ; Ophthalmic Artery/*physiopathology/*ultrasonography ; Middle Aged ; Male ; Humans ; Hemodynamic Processes ; Female ; Child ; Adult ; Adolescent

PURPOSE: This study was a systematic review and meta-analysis of the effects of exercise programs in patients with type II diabetes mellitus. METHOD: Two investigators systematically searched and reviewed English articles from PUBMED from 1988 to 2004, selecting randomized controlled trials on structured exercise programs for DM patients. Out of 87 studies identified, a meta analysis was done for eleven studies which satisfied inclusion criteria and focused on glycemic indices, lipid indices, and cardiac function indices. RESULTS: The means and standard deviations were compared for experimental groups that received exercise-only or exercise and diet programs and control groups that received no intervention or only diet education. The groups were considered homogeneous as the p value of the Q score in each variable group was over 0.05. The experimental groups demonstrated a moderate positive effect on HbA1c and VO2max (d=0.55 & 0.5), and a small positive effect on fasting blood glucose and cholesterol (d=0.38 & 0.27) compared to the control groups. HDL and LDL cholesterol levels, however, showed a very low positive effect (d=0.11 & 0.12) in the experimental groups. Aerobic exercise was more beneficial than resistance exercise on HbA1c (d=0.59 vs 0.28) in the groups. CONCLUSIONS: Regular exercise has a positive effect on HbA1c, fasting blood glucose, total cholesterol, HDL cholesterol, LDL cholesterol, and VO2max in Type 2 diabetic patients.
Oxygen Consumption ; Middle Aged ; Male ; Lipids/*blood ; Humans ; Hemoglobin A, Glycosylated/analysis ; Hemodynamic Processes ; Female ; *Exercise ; Diabetes Mellitus, Type 2/*metabolism/physiopathology/therapy ; Blood Glucose/*analysis

BACKGROUND: Hyperdynamic circulation due to reduced peripheral vascular resistance and increased cardiac output, and the development of portal hypertension are the hemodynamic changes observed in patients with liver cirrhosis. Such hemodynamic abnormalities appear in patients with late stage liver cirrhosis. Therefore, hemodynamic indices, which represent hyperdynamic circulation and portal hypertension, are significant for the prognosis of patients with liver cirrhosis. The aim of this study was to determine the hemodynamic indices associated with the prognosis of patients with liver cirrhosis. METHODS: A total of 103 patients diagnosed with liver cirrhosis between December 1999 and June 2003, with a mean follow-up period of 73 weeks, ranging from 7 to 168 weeks, were recruited. Using Child-Pugh classification, the mean arterial pressure, heart rate and hepatic venous pressure gradient (HVPG) were measured. The indices of Doppler ultrasonography, including the portal and splenic venous flows, and the resistance of the hepatic, splenic, and renal arteries were also measured using the arterial pulsatility index (PI). The prognostic values of these indices were determined by their comparison with the patient survivals. RESULTS: Significant hemodynamic indices for a bad prognosis were high HVPG (> or=15 mmHg) and renal arterial PI (> or=1.14) (p< 0.05). A Child-Pugh score > or=10 was important for a poor prognosis (p< 0.05). CONCLUSION: Severe portal hypertension (HVPG> or=15 mmHg) and high renal arterial resistance (PI> or=1.14) were valuable hemodynamic indices for the prognosis of patients with liver cirrhosis. Therefore, it was concluded that the measurement of these hemodynamic indices, in addition to the Child-Pugh classification, is helpful in the prognosis of patients with liver cirrhosis.
Female ; *Hemodynamic Processes ; Humans ; Korea/epidemiology ; Liver Cirrhosis/*mortality/*physiopathology ; Male ; Middle Aged ; Prognosis ; Survival Rate

In the present study, we tested whether maintenance of adequate cerebral perfusion pressure (CPP) by pharmacologically preventing systemic hypotension with dopamine infusion would prevent cerebral ischemia and attenuate energy depletion and neuronal injury even though intracranial pressure remains elevated in a newborn piglet meningitis model. Cerebral blood flow, measured at the end of the experiment using fluorescent microspheres, was significantly increased by dopamine infusion. The decreased cerebral cortical cell membrane Na+, K+-ATPase activity and increased lipid peroxidation products, indicative of meningitis-induced brain damage, were significantly attenuated by dopamine infusion. Dopamine also significantly attenuated the meningitis-induced reduction in both brain ATP and phosphocreatine levels and the increase in brain lactate level. In summary, maintenance of adequate CPP with dopamine prevented cerebral ischemia, reduced cerebral energy depletion, and attenuated brain injury in neonatal bacterial meningitis.
Animals ; Animals, Newborn ; Brain/cytology/drug effects/*physiology ; Cell Membrane/*metabolism ; Cerebrovascular Circulation/*drug effects ; Dopamine/metabolism/*pharmacology ; Fluorescent Dyes/metabolism ; Hemodynamic Processes ; Meningitis, Escherichia coli/*metabolism ; Microspheres ; Random Allocation ; Regional Blood Flow ; Support, Non-U.S. Gov't ; Swine

Increased or decreased pulmonary blood flow (PBF) and an increased pulmonary vascular resistance (PVR), represent common and important change in pulmonary hemodynamics. In this study, we constructed 3 hemodynamic models in 5 dogs, that is, an increased and a decreased PBF model, and an increased PVR model. A CT perfusion scan was performed in each hemodynamic model. Perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT), and maximal slope (MS) were calculated automatically by specialized software and analyzed for changes according to hemodynamic status. In terms of the normal state, blood flow was affected by gravity and dependent area showed higher BF and BV and lower MS and MTT than the non-dependent area. The decreased PBF model showed a significant increase in BF and MS (p=0.046, 0.005) but no significant change in BV (p > 0.05), and a slight elongation of MTT (p > 0.05) versus the normal state. The increased PBF model showed a slightly increased BV and a slightly decreased MTT (p > 0.05). The increased PVR model showed significant reduction in BF, BV, and MS (p < 0.000, 0.007, 0.000) and a slight increase in MTT, but without statistical significance (p > 0.05). However, it was noticeable that the distribution of MTT with respect to gravity in the normal lung was completely reversed in the increased PVR model. In conclusion, based on our understanding of perfusion characteristic in normal state, abnormal regional hemodynamic changes in the lung can be detected and evaluated. Predicting changes in pulmonary vascular resistance should be possible by a thorough analysis of CT perfusion parameters.
Animals ; Dogs ; *Hemodynamic Phenomena ; *Pulmonary Circulation ; *Radiography, Thoracic ; *Tomography, X-Ray Computed