Biomedical subjects

Carlos L del Rio

Publications and source records attributed to Carlos L del Rio.

3 recordsLinked to original sources

PubMed2006

Vacuum-assisted apical suction devices induce passive electrical changes consistent with myocardial ischemia during off-pump coronary artery bypass graft surgery.

OBJECTIVE: Off-pump coronary artery bypass graft surgery is common therapy to completely revascularize diseased hearts. In order to graft posterior arteries in this procedure, the heart must be lifted from the chest cavity and manipulated to expose the surgical field using an apical suction device. This suction device may cause unwanted myocardial ischemia. METHODS: In this observational study, we measured myocardial electrical impedance, a parameter that responds to myocardial ischemia, as well as ST-segment changes during off-pump coronary artery bypass graft surgery in 12 patients with two-vessel coronary artery disease undergoing revascularisation of the left anterior descending and the posterior descending coronary arteries. During the posterior descending artery revascularisation phase of the procedure the apical suction device was oriented over the electrodes used to measure myocardial electrical impedance, thus allowing us the opportunity to assess myocardial ischemia in this region of the heart. RESULTS: In these 12 patients, myocardial electrical impedance progressively increased under the suction device during posterior coronary artery revascularisation, suggesting that myocardial ischemia developed in this region of the myocardium. ST-segment changes were negligible while the heart was vertically displaced (and the suction device attached), but increased immediately when the heart was returned to the neutral anatomical position. CONCLUSION: Our data suggest that the apical suction device may cause ischemia while the heart is vertically displaced and electrically disconnected from the body. Under these conditions, ST-segment changes may not detect myocardial ischemia. Myocardial electrical impedance has the potential to reliably detect intraoperative myocardial ischemia under these circumstances.

Coronary Artery Bypass, Off-Pump↗

PubMed2005

Correlation of autologous skeletal myoblast survival with changes in left ventricular remodeling in dilated ischemic heart failure.

OBJECTIVES: The effect of autologous skeletal myoblast transplantation has not been rigorously studied in the setting of end-stage ischemic heart failure free of concomitant coronary revascularization. The aims of the present study were to determine autologous skeletal myoblast survival and its effects on left ventricular function and remodeling in sheep with dilated ischemic heart failure. METHODS: Ischemic heart failure (left ventricular ejection fraction, 30% +/- 2%; left ventricular end-systolic volume index, 82 +/- 9 mL/m2) was created in sheep (n = 11) with serial left circumflex coronary artery microembolizations. Instruments were inserted for the long-term determination of left ventricular global and regional dimensions, hemodynamics, and pressure-volume analysis after autologous skeletal myoblast transplantation (approximately 3.0 x 10(8) myoblasts; heart failure plus autologous skeletal myoblast group, n = 5) or without (heart failure-control group, n = 6). Measurements were performed in conscious animals. RESULTS: Autologous skeletal myoblast-derived skeletal muscle was found in all injected animals at 6 weeks. In ischemic heart failure, autologous skeletal myoblast cardiomyoplasty failed to improve systolic (left ventricular ejection fraction, 29% +/- 4%; dP/dT(max), 2863 +/- 152 mm Hg/s; end-systolic elastance, 1.6 +/- 0.22) or diastolic (left ventricular end-diastolic pressure, 21 +/- 2 mm Hg; time constant of relaxation (Tau), 34 +/- 4 ms; dP/dT(min), -1880 +/- 68 mm Hg/s) function. There was, however, attenuation in the left ventricular dilatation after autologous skeletal myoblast transplantation (change in end-systolic volume index, 14% +/- 4% vs 32% +/- 6%; P < .05). The effects of autologous skeletal myoblast-derived skeletal muscle were exclusive to the left ventricular short-axis dimension and dependent on autologous skeletal myoblast survival (R2 = 0.59, P = .006, n = 11). CONCLUSIONS: Autologous skeletal cardiomyoplasty was able to attenuate left ventricular remodeling in sheep with end-stage ischemic heart failure.

Animals↗

PubMed2005

Early time course of myocardial electrical impedance during acute coronary artery occlusion in pigs, dogs, and humans.

Changes in myocardial electrical impedance (MEI) and physiological end points have been correlated during acute ischemia. However, the importance of MEI's early time course is not clear. This study evaluates such significance, by comparing the temporal behavior of MEI during acute total occlusion of the left anterior descending coronary artery in anesthetized humans, dogs, and pigs. Here, interspecies differences in three MEI parameters (baseline, time to plateau onset, and plateau value normalized by baseline) were evaluated using Kruskal-Wallis ANOVA and post hoc tests (P < 0.05). Noteworthy differences in the MEI time to plateau onset were observed: In dogs, MEI ischemic plateau was reached after 46.3 min (SD 12.9) min of occlusion, a significantly longer period compared with that of pigs and humans [4.7 (SD 1.2) and 4.1 min (SD 1.9), respectively]. However, no differences could be observed between both animal species regarding the normalized MEI ischemic plateau value (15.3% (SD 4.7) in pigs, vs. 19.6% (SD 2.6) in dogs). For all studied MEI parameters, only swine values resembled those of humans. The severity of myocardial supply ischemia, resulting from coronary artery occlusion, is known to be dependent on collateral flow. Thus, because dogs possess a well-developed collateral system (unlike humans or pigs), they have shown superior resistance to occlusion of a coronary artery. Here, the early MEI time course after left anterior descending coronary artery occlusion, represented by the time required to reach ischemic plateau, was proven to reflect such interspecies differences.

Acute Disease↗