Detection of coronary stenoses and quantification of the degree and spatial extent of blood flow mismatch during coronary hyperemia with myocardial contrast echocardiography.

BACKGROUND: We hypothesized that the degree and spatial extent of blood flow mismatch in beds supplied by stenoses that are not flow-limiting at rest can be quantified with myocardial contrast echocardiography (MCE) using left atrial (LA) and right atrial (RA) injections of contrast during pharmacologically induced coronary hyperemia. METHODS AND RESULTS: In 12 open-chest dogs, MCE was performed and myocardial blood flow (MBF) was measured by use of radiolabeled microspheres at baseline and during phenylephrine-induced coronary hyperemia. In the presence of this drug, stenoses were placed during different stages on the left anterior descending (LAD) and left circumflex (LCx) coronary arteries, and MCE and MBF assessments were performed. LA injections of 2 mL of 0.5 billion/mL microbubbles (mean diameter, 4.3 microns) were performed at each stage in all 12 dogs, and RA injections of 10 mL of 6 billion/mL microbubbles (mean diameter, 3.7 to 5.3 microns) were administered in 7 dogs. MCE images in which the contrast disparity between the LAD and LCx beds was maximal were digitally subtracted from precontrast images, and mean videointensities in these beds were measured after the dynamic range of gray-scale intensities was increased in the subtracted image and the image was color coded. The region showing hypoperfusion during LAD stenosis was planimetered and expressed as a percentage of the myocardial area in the short-axis slice. There was an excellent correlation between the LAD/LCx bed videointensity ratio and LAD/LCx bed MBF ratio (y = 0.5x + 0.44, r = .91, P < .001) during 57 LA injections. There was also an excellent correlation between the hypoperfused bed size on MCE during LA injection of contrast in the presence of LAD stenosis and the hypoperfused myocardium as determined by radiolabeled microspheres (y = 0.8x + 4.2, r = .90, P < .001, SEE = 2.4, n = 11). The anterior myocardium was opacified in 6 dogs receiving RA injections of contrast, and the hypoperfused area during LAD stenosis correlated closely with that determined by radiolabeled microspheres (y = 0.86x + 3.4, r = .93, P < .01). CONCLUSIONS: Coronary stenoses, which are not flow limiting at rest, can be detected and the degree and spatial extent of blood flow mismatch during pharmacologically induced coronary hyperemia can be quantified with MCE using LA and RA injections of contrast. Thus, it is possible that the severity of coronary stenoses and the quantum of myocardium in jeopardy could be quantified in the future with MCE using venous injection of contrast.

[Transesophageal echocardiography in atrial fibrillation as diagnosis of embolic source and its relation with embolic accidents]. / Ecocardiografia transesofágica na fibrilação atrial como diagnóstico de fonte embolígena e sua relação com acidentes embólicos.

PURPOSE: To determine, by means of transesophageal echocardiography (TEE), the risk factors for intracavitary thrombosis or prethrombotic state and for embolic accidents in patients with atrial fibrillation. METHODS: We studied 49 patients with chronic atrial fibrillation, submitted to clinical examination, EKG, chest X-ray, and TEE. RESULTS: Thirty percent of patients had valvopathies, 29% myocardiopathies, intracavitary thrombus or prethrombotic state were found in 37%, 40% of them had embolic accidents. We did not find statistical significance between myocardiopathies and valvulopathies. The left atrial diameter did not preview embolic accidents. We have observed 6 patients without structural cardiopathies, three of them presented embolic events, and one prethrombotic state. CONCLUSION: Embolic phenomena are inherent to atrial fibrillation and independent of structural cardiopathies, with indication to prophylactic use of oral anticoagulants.

[Primary rhabdomyosarcoma of the heart in children. A case report]. / Rabdomiosarcoma primário do coração em criança. Relato de caso.

The authors report a case of a child, 10 years old with a primary rhabdomyosarcoma of the heart that obstructed both caval veins. The clinical picture that lasted just three months before the admission was characterized by persistent fever, accentuated loss of weight and a very deteriorated general aspect. We emphasize the clinical aspects and other subsidiary elements that easily allowed to make the precise diagnosis in life as well as the therapeutic measures and follow up, besides a review of the literature, where it was confirmed the rarity of this pathological entity.

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.

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]. / Avaliação da insuficiência aórtica na dissecção de aorta. Importância da ecocardiografia intraoperatória na conservação da valva. Relato de caso.

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.

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.