Stimulated preconditioned skeletal muscle cardiomyoplasty. An effective means of cardiac assist

Skeletal muscle grafts can be used to mechanically assist the failing heart. In 13 mongrel dogs, latissimus dorsi muscle was preconditioned in situ for 6-8 weeks. Biopsy samples of the muscles were obtained for histochemical analysis. In seven dogs, muscle force and fatigue were compared in conditioned and contralateral unconditioned (controls) muscles. In six dogs, latissimus dorsi cardiomyoplasty was performed in propranolol-induced acute heart failure, and its effects were evaluated by hemodynamic and echocardiographic parameters. Muscle conditioning was responsible for latissimus dorsi transformation to a muscle with predominantly fatigue-resistant type I fibers. Conditioned muscles developed less initial force (-27 +/- 6%) and a longer contraction time (+32 +/- 4%) (p less than 0.05) but did not show fatigue for less than 15 minutes. With synchronous pulse-train stimulation of the muscle flap, cardiac output increased from 1.4 +/- 0.1 (mean +/- SD) to 2.0 +/- 0.2 l/min (p less than 0.05), pulmonary wedge pressure decreased from 16.3 +/- 0.9 to 12.1 +/- 1.4 mm Hg (p less than 0.05), and left ventricular end-diastolic pressure decreased from 18 +/- 2.0 to 13.5 +/- 1.4 mm Hg (p less than 0.05). Echocardiographically derived ejection fraction increased from 39.3 +/- 2.4% to 59.6 +/- 2.9% (p less than 0.05), and fractional shortening increased from 15.4 +/- 1.1% to 26.3 +/- 1.7% (p less than 0.05). Thus, chronic stimulation of skeletal muscles induces fiber transformation and increases resistance to fatigue and force development. Cardiomyoplasty, on the other hand, improves ventricular function in the presence of acute heart failure. This surgical technique represents an alternative method of treatment for advanced myocardial failure.

Determinants of survival in endomyocardial fibrosis

This study describes the clinical course of 108 patients with endomyocardial fibrosis. There were 76 females and 32 males, with a mean age of 35 years. All patients underwent cardiac catheterization. The angiographic data show that 64 (59%) patients had biventricular involvement. From a clinical point of view, 91 (84%) were in New York Heart Association functional classes III and IV. According to the right and left ventricular intensity of fibrosis, the patients were classified as mild (40 [37%]), moderate (36 [33%]), or severe (32 [30%]) for the right ventricle and mild (19 [18%]), moderate (61 [56%]), or severe (28 [26%]) for the left ventricle. Tricuspid regurgitation was observed in 63 (58%) patients and mitral regurgitation in 65 (60%) patients. Fifty patients in functional classes III and IV underwent surgical treatment. Survival curves constructed according to functional classes showed better prognosis for those in classes I and II (p = 0.0452). Survival curves for patients in classes III and IV for clinical and surgical treatment showed a trend toward better results for the surgical group. Analysis of factors that may have influenced the course of endomyocardial fibrosis showed that biventricular involvement (moderate or severe), right ventricular fibrosis, and presence of tricuspid and mitral regurgitation were associated with greater mortality.

[Ebstein's anomaly associated with ventricular septal defect. A case report]

The authors report a case of Ebstein's anomaly associated to a ventricular septal defect. It is a rare association which leads to a poor prognosis of the disease. They emphasize the clinical findings and the complementary data that lead to the definite diagnosis.

Cardiomyoplasty benefits in experimental myocardial dysfunction

Beneficial effects of cardiomyoplasty have been documented and the use of this technique in the treatment of dilated cardiomyopathy have been suggested. This study was undertaken to evaluate the effectiveness of stimulated preconditioned latissimus dorsi muscle flaps wrapped around the heart in order to restore ventricular contractility in six adult mongrel dogs with induced myocardial dysfunction by administration of beta blockers and volume loading. Hemodynamic and two-dimensional echocardiographic evaluation were performed 1 week after the surgical procedure and immediately after heart failure induction. With synchronous pulse train electrical stimulation, cardiac output increased from 1.46 +/- 0.13 (+/- SD) to 2.01 +/- 0.16 L/min (p less than 0.01), pulmonary wedge pressure decreased from 15.5 +/- 1.2 to 11.3 +/- 1.6 mmHg (p less than 0.01) and left ventricular end-diastolic pressure from 18.3 +/- 2.4 to 13.5 +/- 1.4 mmHg (p less than 0.04). Echo derived left ventricular ejection fraction increased from 39.3 +/- 2.4 to 59.6 +/- 2.9% (p less than 0.01) and segmental wall shortening from 15.4 +/- 1.2 to 26.3 +/- 1.7% (p less than 0.01), inclusive when the muscle flap was wrapped only around the left ventricle. In conclusion, this study suggests that cardiomyoplasty may be an alternative method of treatment for irreversible cardiomyopathy, including in patients with a great cardiac enlargement in which muscle flap may only be wrapped partially around the heart.

[Evaluation of aortic insufficiency in aortic dissection. Significance of intraoperative echocardiography on the conservation of the valve. A case report]

A 34-year old man presented with dyspnea and a new murmur of aortic regurgitation (AR). Two months before he had a episode of acute chest pain. The diagnosis of type A chronic aortic dissection was done on the basis of clinical signs and digital angiography. At surgery, intraoperative two-dimensional echocardiography (Iop Echo) showed a large intimal flap prolapsing into the leaflets during diastole causing AR, without primary involvement of the aortic valve. The aorta was transected just above the valve commissures and a 30 mm woven graft was sutured end to end. The false lumen was closed distally and incorporated into the graft-aorta suture line. Valve replacement was not performed. After the surgical procedure, a Iop Echo indicated competence of the aortic valve by means of contrast injection in the aortic root. AR due to the interference of an intimal flap with the aortic leaflets was not yet been reported. To our knowledge, this is the first case of this mechanism and illustrates the potential value of Iop Echo in diagnosis of aortic dissection.

Biomechanical circulatory assistance. Importance of aerobic capacity of normal and conditioned skeletal muscles

To define more efficient use of biomechanical circulatory assistance, the contracting and fatigue characteristics of normal and conditioned latissimus dorsi of seven adult mongrel dogs were analyzed. The conditioned muscles underwent vascular adaptation and electrical stimulation with burst frequency of 50 Hz in rates of 60 and 120 contractions per minute for 6 to 8 weeks. They were compared with unconditioned contralateral controls by isometric force measurements. Normal and transformed muscles exhibited the same optimum pacing parameters (burst frequencies from 50 Hz up and train durations from 150 msec) with supramaximal amplitude stimulation. Conditioned muscles showed initial smaller forces (-27%) and longer contraction times (+32%). Fatigue curves of unconditioned muscles for different duty cycles showed marked initial decreases and proportional stable values of force after some minutes, with equal final tension time indexes under these conditions (20 +/- 3 KgF seg/min 100 g). Conditioned muscles maintained stable force for same duty cycles and a greater tension time index during prolonged conditions (68 +/- 6 KgF seg/min 100 g). This study revealed that normal and conditioned skeletal muscles are capable of maintaining steady state work depending upon their aerobic capacity and suggests that these muscles may undergo adaptive transformation while contracting in a synchronous fashion with the heart during variable duty cycles.

Bullet in the interventricular septum: report of surgical removal in two cases

We have had the opportunity of treating two patients who were wounded by gunshot bullets lodged in the interventricular septum (IVS). The first patient was treated by suture of the ventricle in another hospital. He was then directed to our institution where cineangiocardiography and echocardiogram revealed a bullet in the IVS close to the outlet of the left ventricle. The bullet was removed using cardiopulmonary bypass (CPB), through an incision in the right side of the septum. The patient's recovery was satisfactory, and he was asymptomatic in the 18th postoperative month. In January 25th, 1987 we attended another patient hit by a firearm bullet. The X-Ray revealed a bullet in the cardiac area. The patient was submitted to a median sternotomy and an intraoperative echocardiogram was carried out, which showed that the bullet was located in the interventricular septum. With CPB the right atrium was opened up and the bullet was removed from the interventricular septum. The patient's evolution was also satisfactory. These reports demonstrate the importance of complete evaluation of patients with thoracic wounds and the feasibility of diagnosis and surgical removal of bullets from the interventricular septum.

Heart transplantation in patients with Chagas' disease cardiomyopathy

Among 26 heart transplant patients, four had Chagas' disease cardiomyopathy. They were male patients, aged 28 to 43 years; three were in New York Heart Association class IV, and one was in class II but with refractory arrhythmias. The immunosuppressive protocol was cyclosporine and steroids in the first patient, and cyclosporine, azathioprine, and steroids in the last patient. Three patients had one or more rejection episodes, and one had none. One patient had a lymphoproliferative intestinal disease. Three patients had a new acute phase of Chagas' disease in postoperative days 59, 81, and 420, with fever, skin lesions, and myocarditis. The Trypanosoma cruzi was found in skin lesions in all three patients and in the myocardial biopsy in two patients. The laboratory tests did not show the expected results for the acute phase. All the alterations were reversed by specific therapy in a few days. One patient died on postoperative day 197 from rejection, and the immunosuppression was diminished because of the lymphoproliferative disease; the others were well 107, 160, and 500 days after the transplantation. The conclusions were as follows: (1) It seems that steroid pulse therapy predisposes the patient to a new acute phase of Chagas' disease. (2) Clinical presentation and laboratory test results of the acute phase are not the usual. (3) Specific drug therapy reverses all the alterations of this acute phase in a few days. (4) Although additional care is necessary and specific complications are expected, heart transplantation can be done with good results in patients with Chagas' cardiomyopathy.

Immunopathologic studies in myocardial biopsies of patients with Chagas' disease and idiopathic cardiomyopathy

Right ventricular endomyocardial biopsies were studied in 30 patients, 15 with myocardiopathy from chronic Chagas'disease and 15 with idiopathic congestive myocardiopathy; five other myocardial samples were taken at necropsies of patients with chronic Chagas' disease. The authors tried to establish by means of direct immunofluorescence techniques whether there were immunoglobulins G, A and M, fibrinogen and C3 complement deposition in the myocardium; only one of these 30 patients exhibited a positive reaction to IgG, it was a patient with idiopathic congestive myocardiopathy. All fragments from patients with Chagas' disease showed no response to any of the fluorescent conjugates. These findings do not support the idea that anti-myoeardial antibodies have pathogenic importance in the evolution of dilated or chagasic myocardiopathies.