Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the fir...Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function.展开更多
Objective To report Medtronic experiences with the development of animal models for atrial fibrillation （AF） and chronic heart failure （CHF） using high-rate pacing for AF and microemboli for CHF. Methods For the A...Objective To report Medtronic experiences with the development of animal models for atrial fibrillation （AF） and chronic heart failure （CHF） using high-rate pacing for AF and microemboli for CHF. Methods For the AF model, an atrial lead was attached to a Medtronic SynergyTM neurostimulator, which was programmed to stimulate at 50 Hz in an on-off duty cycle. Atrial natfiuretic peptide （ANP）, brain natriuretic peptide （BNP） and N-terminal pro brain nalriuretic peptide （NT-proBNP） were assayed at select time points. For CHF model, a serial injection of 90 μm polystyrene microspheres at 62,400 beads/mL （Polybead, Polysciences, Inc.） was performed to induce global ischemia, either with weekly monitoring and embolization schedule （group 1, n = 25） or with biweekly monitoring and emboliation schedule （group 2, n = 36 ）. Echocardiograms were used along with ventriculograms and magnetic resonance imaging scans weekly to assess cardiac function and ANP, BNP and NT-proBNP were monitored. Results For the AF model, the days to sustained AF for four animals following surgery were 7, 25, 21 and 19, respectively; For the CHF model, the days to meet CHF endpoints were 116 in group 1 and 89 in group 2. For both AF and CHF models, NT-proBNP correlated well with the development of disease states. Conclusion Our experience for the development and assessment of AF and CHF dog models may help researchers who are in search for animal model for assessing the safety and efficacy of a device-based therapy.展开更多
文摘Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function.
文摘Objective To report Medtronic experiences with the development of animal models for atrial fibrillation （AF） and chronic heart failure （CHF） using high-rate pacing for AF and microemboli for CHF. Methods For the AF model, an atrial lead was attached to a Medtronic SynergyTM neurostimulator, which was programmed to stimulate at 50 Hz in an on-off duty cycle. Atrial natfiuretic peptide （ANP）, brain natriuretic peptide （BNP） and N-terminal pro brain nalriuretic peptide （NT-proBNP） were assayed at select time points. For CHF model, a serial injection of 90 μm polystyrene microspheres at 62,400 beads/mL （Polybead, Polysciences, Inc.） was performed to induce global ischemia, either with weekly monitoring and embolization schedule （group 1, n = 25） or with biweekly monitoring and emboliation schedule （group 2, n = 36 ）. Echocardiograms were used along with ventriculograms and magnetic resonance imaging scans weekly to assess cardiac function and ANP, BNP and NT-proBNP were monitored. Results For the AF model, the days to sustained AF for four animals following surgery were 7, 25, 21 and 19, respectively; For the CHF model, the days to meet CHF endpoints were 116 in group 1 and 89 in group 2. For both AF and CHF models, NT-proBNP correlated well with the development of disease states. Conclusion Our experience for the development and assessment of AF and CHF dog models may help researchers who are in search for animal model for assessing the safety and efficacy of a device-based therapy.
