Advancements in pressure–volume catheter technology – stress remodelling after infarction

New Findings•  What is the topic of this review? The gold standards for assessing heart function in experimental animals are magnetic resonance imaging or high‐frequency ultrasound; however, these are not accessible in many laboratories. We review here the use of the new microconductance catheter technologies to assess cardiac function in rodent models of the diseased heart. •  What advances does it highlight? Recent advances in the technology of conductance and admittance catheter systems provide an inexpensive, readily available method to assess cardiac function in rodents. We discuss the common pitfalls in using this technique and present evidence showing that its reliability and reproducibility are similar to ultrasound.Microconductance catheters have been successfully applied to measure left ventricular (LV) function in the mouse to assess cardiac or pharmacological interventions for a number of years. New complex admittance methods produce an estimate of the parallel admittance of cardiac muscle that can be used to correct the measurement in real time. This contrasts with existing conductance technologies that require in vivo calibration using a bolus of hypertonic saline. Here, we report the application of this emerging technology in the context of myocardial infarction and LV remodelling. Using a combination of high‐resolution ultrasound and LV conductance catheters, we compared measures of LV function using an admittance system and a traditional conductance‐derived pressure–volume (PV) system. We subjected C57BL/6 mice to focal myocardial ischaemia–reperfusion by transient ligation of the left anterior descending coronary artery and assessed cardiac function with different systems to determine the reliability and accuracy of these methods to distinguish between normal and dysfunctional ventricle. We demonstrate that the admittance PV system, in our hands, provides a straightforward solution for assessing LV function in mice. Using this technique in combination with other established methods, we measured LV dysfunction following coronary artery occlusion and reperfusion, which can be ameliorated using a known preconditioning agent (CORM‐3), and found that functional read‐outs are representative of other methods. We have found that, especially in diseased tissue, LV pressure–volume loops derived from complex admittance provide a reproducible and reliable method of determining LV function without the need for technically challenging calibration. Our data suggest that admittance records accurate/physiological LV cavity volumes when compared with other invasive methods in the same animal. This emerging technology is both effective and reproducible for measuring LV function and dysfunction in the mouse, without the need for complicated interventions to calibrate the measurements or training in a new technology. This may mark the way towards a fast and accurate assessment of murine cardiac function in normal animals and disease models.