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Biomedical subjects

D T Hsu

Publications and source records attributed to D T Hsu.

At least 37 records · Page 2Linked to original sources

Incidence and outcome of primary Epstein-Barr virus infection and lymphoproliferative disease in pediatric heart transplant recipients.

BACKGROUND: The objective of this study was to assess the relationship between Epstein-Barr virus (EBV) infection and posttransplantation lymphoproliferative disease (PTLD) in pediatric heart transplant recipients. EBV is implicated in the development of PTLD. However, the relationship between primary EBV infection and PTLD is not well understood. METHODS: Serial EBV titers were determined prospectively in 50 children before and after heart transplantation. Results were correlated with the development of PTLD. The clinical presentation, management, and outcome of PTLD were characterized. RESULTS: Before transplantation, EBV titers were positive in 19 and negative in 31 patients. After transplantation, all EBV-positive patients remained positive; 1 developed PTLD. Among EBV-negative patients, 12 of 31 remained negative; none developed PTLD. Nineteen patients demonstrated serologic evidence of primary EBV infection after heart transplantation; 12 developed PTLD. Mean follow-up after heart transplantation was 3.3 years (range 0.4 to 8.4 years). Mean time from heart transplantation to histologic confirmation of PTLD was 29 months (range 3 to 72 months). Survival with PTLD was 92%. CONCLUSIONS: Twelve of 13 pediatric heart transplant recipients who developed PTLD had evidence of primary EBV infection. Serial monitoring of EBV titers may lead to earlier identification and improved treatment of PTLD.

Adolescent↗

Outcome after the single-stage, nonfenestrated Fontan procedure.

BACKGROUND: A completed Fontan circulation is the goal in the management of patients with single-ventricle physiology. To achieve this end, a two-stage rather than a single-stage approach is carried out routinely at many centers. Some groups have advocated baffle fenestration for virtually all patients to minimize post-Fontan complications. Other centers perform single-stage Fontan operations and do not fenestrate. Thus controversies have arisen regarding the indications for the staged procedure versus single stage and for fenestration versus no fenestration. METHODS AND RESULTS: The preoperative risk factors and postoperative course were characterized in 61 consecutive patients (median age, 3.3 years) undergoing a single-stage, nonfenestrated Fontan. The patients were followed for 3.5+/-1.9 years. The relationship between preoperative risk factors and mortality and morbidity was assessed. Preoperative risk factors assessed included age <2 years (n=18), branch pulmonary artery stenosis (n=20), elevated mean pulmonary artery pressure >15 mm Hg (n=16), atrioventricular valve regurgitation (n=5), and decreased ventricular function (n=2). Total caval pulmonary anastomosis was performed in 53 patients. Additional surgery was required at the time of the Fontan in 25 patients (41%). The median duration of mechanical ventilation was 1 day; median chest tube drainage was 5.5 days (range, 1 to 35). Oxygen saturation rose significantly postoperatively, from 83% to 95%. Early mortality was 4.9%; one patient died from pacemaker failure 9 months postoperatively, and one patient underwent successful heart transplant 4 months post-Fontan. One- and 5-year actuarial survival was 93%. No preoperative risk factor was associated with a failed Fontan or significant effusions. CONCLUSIONS: A single-stage, nonfenestrated Fontan was performed in a large group of patients with excellent surgical results and intermediate outcome. There is no evidence that a two-stage approach and/or baffle fenestration is required for a large cohort of patients who are candidates for a Fontan operation.

Adolescent↗

Myocardial edema: comparison of effects on filling volume and stiffness of the left ventricle in rats and pigs.

BACKGROUND: This study compared the adverse effects of crystalloid-induced myocardial edema on left ventricular (LV) compliance in small and large hearts. METHODS: Plegisol (289 mOsm/L) was perfused into the coronary arteries of pigs (n = 8) and 1:1 dilute Plegisol (145 mOsm/L) into the coronary arteries of rats (n = 6). Pressure-volume relations, heart weight, and water content were then determined. The pressure-volume relations were compared using an LV volume at a pressure of 10 mm Hg. RESULTS: Edema in rats was associated with significant (p < 0.05) increases in heart weight (1.1 +/- 0.0 g versus 1.4 +/- 0.1 g [average +/- standard error of the mean]) and water content (76.8% +/- 0.4% versus 81.3% +/- 0.8%), but an increase in LV stiffness (7.91 +/- 0.52 versus 9.27 +/- 1.42) and a decrease in the LV volume at 10 mm Hg (0.25 +/- 0.02 mL versus 0.14 +/- 0.05 mL) were not statistically significant. Edema in pigs was associated with statistically significant (p < 0.05) increases in LV stiffness beta (0.050 +/- 0.004 versus 0.072 +/- 0.008), heart weight (207 +/- 8 g versus 274 +/- 9 g), and water content (79.8% +/- 0.6% versus 85.3% +/- 0.6%) and a significant decrease in the LV volume at 10 mm Hg (88.4 +/- 5.8 mL versus 60.4 +/- 6.8 mL). CONCLUSIONS: Myocardial edema is associated with an increase in water content and LV stiffness and a decrease in the LV volume at 10 mm Hg in both species. In rats, however, the water content is smaller in the control state and a more hypotonic perfusate is needed to induce a given degree of edema.

Animals↗

Long-term survivors of pediatric heart transplantation: a multicenter report of sixty-eight children who have survived longer than five years.

OBJECTIVE: Short-term survival after pediatric heart transplantation is now excellent, but ultimately the efficacy of this procedure will depend on duration and quality of survival. We sought to evaluate the clinical course of long-term survivors of heart transplantation in childhood. METHODS: Patients who had undergone heart transplantation at the university hospitals of Stanford, Columbia, and Pittsburgh between 1975 and 1989 and survived longer than 5 years from transplantation were identified and their clinical courses retrospectively reviewed. RESULTS: Sixty eight children have survived more than 5 years from transplantation, and 60 (88%) are currently alive with a median follow-up of 6.8 years (5 to 17.9 years). Thirteen have survived more than 10 years from transplantation. Renal dysfunction caused by immunosuppressive agents was common, and two patients required late renal transplantation. Lymphoproliferative disease or other neoplasm occurred in 12 patients, but none resulted in death. Coronary artery disease was diagnosed in 13 patients (19%), leading to retransplantation in eight. Death after 5 years was related to acute or chronic rejection in 5 of 8 cases. Two of the deaths were directly related to noncompliance with immunosuppressive medication. All survivors are in New York Heart Association class 1. CONCLUSIONS: Long-term survival with good quality of life can be achieved after heart transplantation in childhood, though complications of immunosuppression remain common. Posttransplantation coronary artery disease is emerging as the main factor limiting long term graft and patient survival.

Adolescent↗

Free composite serratus anterior and rib flaps for tibial composite bone and soft-tissue defect.

Open fracture in the lower extremity often involves composite bone and soft-tissue defects. For patients with extensive segmental bone defects, vascularized fibular transfers can be utilized and are generally accepted as one of the best options for reconstruction of intercalary defects. In some cases, either bilateral tibias and fibulas are fractured or the contralateral fibula is traumatically damaged or absent, precluding free fibular transfer. If an osteocutaneous fibular flap cannot be used to manage such a defect, a composite serratus anterior and rib flap may be considered. Nine composite serratus anterior and rib flaps, with or without latissimus dorsi transfers, were performed in eight patients between August of 1993 and March of 1994. One patient sustained a left knee disarticulation and underwent reconstruction for a right tibial defect. He failed to achieve lower extremity function within 2 years and was considered a failure. One flap failed, and the patient underwent a below-knee amputation. The remaining six patients received seven composite flaps for tibial and calcaneal defects and could ambulate without assistance. Based on this review, we conclude that the composite serratus anterior and rib flap with optional latissimus dorsi muscle can be used for (1) bilateral tibial fibular fractures, (2) contralateral lower limb amputation with fillet of the amputated leg if the leg is present for harvest, (3) contralateral middle-third fracture of the fibula, (4) patients in whom iliac bone is not suitable because of either a bone defect greater than 10 to 12 cm or previous harvest of bone graft, and (5) extensive composite bone and soft-tissue defects.

Adolescent↗

Biventricular assist device as a bridge to transplantation in a pediatric patient.

A 5 1/2-year-old boy with idiopathic cardiomyopathy and rapidly worsening hemodynamic parameters underwent placement of a biventricular assist device as a bridge to transplantation. Direct anastomoses to both the aorta and pulmonary artery with Dacron grafts attached to Carmeda-coated tubing facilitated the support period. Inflow was provided by right atrial appendage and left ventricular apex cannulas. A centrifugal pump provided support for 2 days until a suitable donor was identified. The technique is simple, reproducible, and effective for patients with small body surface areas.

Anastomosis, Surgical↗

Blade balloon atrial septostomy in patients with severe primary pulmonary hypertension.

BACKGROUND: Patients with severe primary pulmonary hypertension have a poor prognosis, but those with a patent foramen ovale may survive longer. A few reports of clinical improvement after blade balloon atrial septostomy in patients with severe pulmonary vascular disease have appeared. The purpose of this study was to systematically evaluate the effects of blade balloon atrial septostomy on clinical signs and symptoms, hemodynamics, and survival in patients with severe primary pulmonary hypertension. METHODS AND RESULTS: Blade balloon atrial septostomy was performed on 15 children and young adults with severe primary pulmonary hypertension. Despite maximal medical therapy, prior to septostomy all patients had recurrent syncope and 8 had severe right heart failure. Thirteen patients survived the procedure. After blade balloon atrial septostomy, no patient experienced further syncope, and signs and symptoms of right heart failure improved in all New York Heart Association Class IV patients. Within 24 hours after the procedure and at follow-up catheterization 7 to 27 months after septostomy, there was a significant increase in cardiac index, resulting in an increase in systemic oxygen transport. There was improved long-term survival in the 13 patients who survived blade balloon atrial septostomy compared with similar groups of primary pulmonary hypertension patients who received standard therapy (P < .05). CONCLUSIONS: Blade balloon atrial septostomy resulted in clinical and hemodynamic improvement and improved survival in selected patients with severe primary pulmonary hypertension.

Adult↗

Heart transplantation in children with congenital heart disease.

OBJECTIVES: The aim of this study was to describe heart transplantation in children with congenital heart disease and to compare the results with those in children undergoing transplantation for other cardiac diseases. BACKGROUND: Reports describe decreased survival after heart transplantation in children with congenital heart disease compared with those with cardiomyopathy. However, transplantation is increasingly being considered in the surgical management of children with complex congenital heart disease. Present-day results from this group require reassessment. METHODS: The diagnoses, previous operations and indications for transplantation were characterized in children with congenital heart disease. Pretransplant course, graft ischemia time, post-transplant survival and outcome (rejection frequency, infection rate, length of hospital stay) were compared with those in children undergoing transplantation for other reasons (n = 47). RESULTS: Thirty-seven children (mean [+/- SD] age 9 +/- 6 years) with congenital heart disease underwent transplantation; 86% had undergone one or more previous operations. Repair of extracardiac defects at transplantation was necessary in 23 patients. Causes of death after transplantation were donor failure in two patients, surgical bleeding in two, pulmonary hemorrhage in one, infection in four, rejection in three and graft atherosclerosis in one. No difference in 1- and 5-year survival rates (70% vs. 77% and 64% vs. 65%, respectively), rejection frequency or length of hospital stay was seen between children with and without congenital heart disease. Cardiopulmonary bypass and donor ischemia time were significantly longer in patients with congenital heart disease. Serious infections were more common in children with than without congenital heart disease (13 of 37 vs. 6 of 47, respectively, p = 0.01). CONCLUSIONS: Despite the more complex cardiac surgery required at implantation and longer donor ischemic time, heart transplantation can be performed in children with complex congenital heart disease with success similar to that in patients with other cardiac diseases.

Adolescent↗

Unreamed interlocking nail versus external fixator for open type III tibia fractures.

We undertook a prospective study comparing the unreamed interlocking nail to Hoffmann external skeletal fixation (ESF) in the treatment of 36 consecutive patients with open type IIIA and IIIB tibia fractures. The choice of interlocking nail or Hoffmann ESF was randomized, ultimately producing four different patient groups: group 1, type IIIA fractures treated by interlocking nail; group 2, type IIIA fractures treated by ESF; group 3, type IIIB fractures with interlocking nail; and group 4, type IIIB fractures with ESF. The average length of follow-up was 20.5 months. The infection rate was highest in group 3 (3 of 8). The malrotation, malunion, and nonunion rates were highest in group 4 and lowest in group 1. These results suggest the unreamed interlocking nail is a good choice for the treatment of open type IIIA tibia fractures, but not recommended for the treatment of open type IIIB tibia fractures because of the high infection rate.

Adolescent↗

Time course of perfusion-induced myocardial edema resolution in rats.

Previous studies have demonstrated that crystalloid coronary perfusion can cause myocardial edema, but the time required for resolution of this edema has not been defined. Accordingly, studies were conducted in 30 rats. Myocardial edema was induced by coronary perfusion with 20 cc/kg of Plegisol (294 mOsm/liter) during aortic occlusion, which produced diastolic arrest. This was followed by whole blood reperfusion, which restored normal contractile function. Duration of reperfusion in minutes was zero (group 0, n = 6), one (group 1, n = 6), five (group 5, n = 6), or fifteen (group 15, n = 6). A control group (n = 6) was studied without edema or reperfusion. Data included heart weight and myocardial water content. Left ventricular pressure-volume curves were measured in groups 1, 5, and 15. Myocardial water content increased significantly from 75.7 +/- 0.5% (SD) in the control group to 79.7 +/- 1.1% (P < 0.05) in group 0 and then decreased significantly to 77.3 +/- 0.7, 75.2 +/- 1.4, and 75.3 +/- 1.6% in groups 1, 5, and 15, respectively. Water content in group 1 was also significantly greater than in groups 5 and 15. Heart weight changes were not statistically significant. Normalized pressure-volume relationships shifted rightward with increasing reperfusion time, but changes were not statistically significant. We conclude that edema induced by crystalloid coronary perfusion of the arrested heart resolves in the beating heart after less than 5 min of blood reperfusion.

Animals↗

[Floating shoulder (ipsilateral scapular neck and clavicle fracture)--two cases report].

Fracture of either clavicle or scapular neck alone are generally stable and have satisfactory results by conservative treatment. However, displaced scapular neck and ipsilateral clavicle fractures are relatively unstable. Those sequelae as drooping shoulder and limited range of motion may develop if treated conservatively. Surgical intervention either fixation of clavicle alone or fixation of clavicle and scapular neck simultaneously can achieve stable reduction of the fractures and prevent those sequelae. We present two cases of floating shoulder treated surgically with excellent results.

Adult↗

Diastolic function in the heterotopic rat heart transplant model. Effects of edema, ischemia, and rejection.

Decreased systolic ventricular function and compliance and increased left ventricular edema and mass have been demonstrated in cardiac allograft rejection. Whether decreased left ventricular compliance in rejection is caused by myocardial edema has not been examined, and compliance in the Ono-Lindsey model has not been reported. Heterotopic rat abdominal cardiac transplantation was performed in ACI isografts (n = 24) and in ACI to Lewis allografts (n = 24). Subgroups were studied on posttransplantation days 0, 1, 3, and 5 (each n = 6). Both transplanted hearts and native hearts were arrested with potassium for the assessment of myocardial water content, heart weight, and the left ventricular pressure-volume relation. In transplanted hearts, myocardial water content did not change in isografts but increased on posttransplantation day 5 in allografts (81.1% on posttransplantation day 5 versus 76.1% on day 0, 77.2% on day 1, and 77.5% on day 3, p < 0.05). Wet and dry heart weight also increased on posttransplantation day 5 in allografts (p < 0.05). The left ventricular pressure-volume relation in transplanted hearts shifted to the left when compared with that in native hearts in all subgroups; these volume differences were statistically significant (p < 0.01) for all pressures above 7.5 mm Hg. This pattern was similar in isografts and allografts on posttransplantation days 0, 1, and 3, and no significant differences between isografts and allografts were demonstrated. On posttransplantation day 5, however, the pressure after a 0.05 ml injection in allografts was greater in transplanted hearts than in native hearts (24 +/- 3 versus 3 +/- 1 mm Hg, p < 0.01). The pressure difference between transplanted and native hearts was also significantly greater in allografts than in isografts (22 +/- 2 versus 6 +/- 1 mm Hg, p < 0.01), indicating an increase in stiffness of allografts. Thus edema and impaired diastolic properties occur concurrently with allograft rejection. Left ventricular volume is abnormal from posttransplantation days 0 to 5 in transplanted hearts but not native hearts in the Ono-Lindsey model with current methods, apparently because of ischemic injury during transplantation.

Animals↗

Intraaortic balloon pump management of refractory congestive heart failure in children.

From December 1975 to September 1989, nine children, ages 0.6-15.8 years (mean = 8.1 years) and weighing 5-44 kg (mean = 24 kg), were identified as requiring intraaortic balloon pump support. Indications included ventricular failure refractory to maximal conventional therapy, inability to wean from cardiopulmonary bypass, and myocardial ischemia. Prior to insertion of the balloon catheter, mean systolic blood pressure was 64 mmHg, one to four cardiotonic medications were being administered, mechanical ventilation was being performed in eight patients, and mean urine output was 0.4 ml/kg/min in eight. Following balloon catheter insertion, mean urine output increased to 0.9 ml/kg/min. Four patients survived following discontinuation of the balloon catheter 12-96 h (mean = 59 h) after initiation. Though complications such as loss of distal lower extremity pulses, sepsis, thrombocytopenia, and abdominal distention were observed, most could be attributed to other causes. Thus, the intraaortic balloon pump is a valuable addition to conventional medical therapy in the treatment of refractory cardiogenic shock in children.

Cardiotonic Agents↗

Decreasing incidence of coronary disease in pediatric cardiac transplant recipients using increased immunosuppression.

BACKGROUND: Coronary artery disease (CAD) is a limiting factor to long-term survival in cardiac transplant recipients, affecting from 30% to 50% of patients by 4 years after surgery. Can the incidence of CAD be lowered with augmentation of immunosuppression? METHODS AND RESULTS: We compared the incidence of CAD in our pediatric transplant population with nine potential risk factors, including immunosuppressive regimen. The study group consisted of 55 patients who survived more than 1 year (or to first angiogram) or had autopsies. Coronary angiograms were performed yearly and compared sequentially. The mean follow-up of 55 patients was 36 months. Mean age was 10.3 +/- 6 years (range, 4 months to 18 years). Thirteen patients received double immunosuppression with cyclosporine and prednisone, and 42 received triple therapy with cyclosporine, prednisone, and azathioprine. Significant CAD occurred in 10 grafts (6 deaths and 3 retransplants). Cause for graft loss in 6 patients with CAD was acute rejection. CAD was detected by angiogram in only 2 patients. Nine of 10 patients received double therapy (P < .001). There was no difference in mean follow-up between immunosuppression groups. There was a higher rejection frequency for double therapy (0.19 +/- 0.16 rejections per patient month) compared with triple therapy (0.07 +/- 0.11). Ten patients were rejection free in the triple therapy group. CONCLUSIONS: We experienced a significant decrease in the incidence of CAD in our pediatric cardiac transplant recipients using increased immunosuppressive therapy. Type of immunosuppressive regimen (double) and rejection frequency were independent predictors for CAD by multivariate analysis.

Azathioprine↗

Exercise performance after pediatric heart transplantation.

BACKGROUND: Children awaiting heart transplantation have severe limitations in their ability to exercise. The purpose of this study was to assess exercise capacity after pediatric heart transplantation and to identify factors influencing exercise performance. METHODS AND RESULTS: Progressive cycle ergometry testing was performed in 31 patients at 1.3 +/- 0.8 years after transplantation, and in 16 patients, follow-up studies were performed at 3.3 +/- 1.3 years after transplantation. Maximum work load (Wmax), peak oxygen consumption (VO2), and maximum heart rate (HRmax) were measured. Exercise capacity was defined as normal if Wmax was > or = 75% of predicted values and decreased if Wmax was < 75% of predicted values. Differences in age at transplantation, sex, diagnosis, duration of heart failure, New York Heart Association class before transplantation, resting cardiac index, body mass index, and rejections per patient month were compared between patients with normal and decreased exercise capacity. At initial study, Wmax was 62 +/- 38 W or 61% of that predicted, peak VO2 was 20 +/- 6 mL.kg-1 x min-1 (63% of that predicted), and HRmax was 136 +/- 22 beats per minute (66% of that predicted) for all 31 patients. Six patients had normal exercise capacity, and 25 patients had decreased exercise capacity. Peak VO2 was significantly higher in the normal versus the decreased exercise capacity patients (26 +/- 5 vs 19 +/- 5 mg.kg-1 x min-1). The mean age at transplantation was significantly less in patients with normal exercise capacity: 8.2 +/- 4.6 versus 12.5 +/- 3.6 years for patients with decreased capacity. On follow-up study, no significant differences in Wmax, peak VO2, or HRmax were found from the initial test. CONCLUSIONS: Similar to results obtained in adult patients, exercise capacity was decreased but stable in pediatric patients after heart transplantation.

Cardiomyopathies↗

Quantitative effects of myocardial edema on the left ventricular pressure-volume relation. Influence of cardioplegia osmolarity over two hours of ischemic arrest.

We previously studied edema and left ventricular pressure-volume relations in a porcine heart model in which edema occurred even with hyperosmolar crystalloid cardioplegia. This susceptibility to edema was attributed to venous occlusion and an initial 20-minute period of ischemia. Results did not demonstrate reversal of edema by hyperosmolar perfusates. Accordingly, in the present study, heart weight, myocardial water content, and left ventricular pressure-volume curves were measured before and after perfusion-induced edema in eight isolated, arrested, hypothermic porcine hearts. Cardioplegic solution was infused 2.1 +/- 0.8 minutes after the onset of ischemia, and the atrioventricular ring was not clamped during the administration of cardioplegic solution. Cardioplegic solution (1 L) was infused at intervals of 33 +/- 6 minutes at 4 degrees C. Solution osmolarity was 380 (Stanford solution) or 294 mOsm/L (Plegisol solution). The perfusion sequence was 380-1, 380-2, 294-1, 380-3. Pressure-volume relations were assessed with the use of left ventricular volume at a pressure of 10 mm Hg and the ventricular chamber stiffness constant, beta, derived from P = alpha e beta V. Perfusions 380-1 and 380-2 did not affect the pressure-volume curve. Perfusion 294-1 increased heart weight and water content (p < 0.05) and decreased left ventricular volume at 10 mm Hg compared with perfusions 380-1, 380-2, and 380-3. In addition, beta increased (0.023 +/- 0.005 versus 0.029 +/- 0.006, p < 0.05) after perfusion 294-1, compared with 380-1. Correlation coefficients for linear regressions between left ventricular volume at 10 mm Hg and heart weight and water content were r = 0.84 and r = 0.70, respectively. We conclude that under conditions similar to those used clinically, the left ventricle of the pig does not develop edema with Stanford solution (380 mOsm/L). Edema does follow Plegisol solution (294 mOsm/L) cardioplegia. Edema and reduced compliance are incompletely reversed by hypertonic cardioplegia. The porcine left ventricle can usefully replicate the clinical model.

Animals↗

Effects of crystalloid, blood, and University of Wisconsin perfusates on weight, water content, and left ventricular compliance in an edema-prone, isolated porcine heart model.

Coronary perfusion with blood and cardioplegic solutions was examined in isolated, arrested, hypothermic porcine hearts. Myocardial water content, heart weight, and left ventricular diastolic pressure-volume curves were measured before and after coronary perfusion. Statistics were based on exponential curve fitting to pressure-volume data and analysis of variance. Thirty-two pig hearts were divided into five experimental groups and a control group; after control measurements, each experimental group underwent three successive coronary perfusions with 1 L of unmodified blood or a solution of controlled osmolarity, 150 mOsm/L (diluted Plegisol solution), 280 mOsm/L (Plegisol solution and albumin), 334 mOsm/L (University of Wisconsin solution), or 380 mOsm/L (Stanford solution). After each perfusion, measurements were repeated. All experiments were completed within 90 minutes. The first perfusion was delayed 20 minutes after excision of the heart to allow for instrumentation. Each experimental group demonstrated a statistically significant increase in heart weight and myocardial water content and a significant decrease in left ventricular compliance after perfusion. Changes were less pronounced with blood than crystalloids. Edema effects were minimized but not prevented by hyperosmolarity. University of Wisconsin solution appeared unique in minimizing progressive edema after the first perfusion. Over the 81 perfusions studied, changes in left ventricular compliance were linearly related to heart weight and water content. We conclude that in this model, in which edema sensitivity is increased by delayed perfusion and venous occlusion, edema is minimized but not eliminated by whole blood and University of Wisconsin solution. The model appears useful in assessing properties of cardioplegia vehicles intended for use in the injured myocardium.

Adenosine↗