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Biomedical subjects

G Merin

Publications and source records attributed to G Merin.

99 records · Page 6Linked to original sources
PubMedDate not supplied

Direct positive inotropic effect of mannitol on the intact canine heart.

Infusion of 25% mannitol into either the circumflex or left anterior descending coronary artery caused a significant increase in myocardial force development, measured by means of strain gauge in 10 anesthetized dogs. The changes were confined to the area perfused. The increase in developed force was dose-dependent, 20% at an infusion rate of 0.55 ml/min, 28% at 1.4 ml/min, 32% at 2.8 ml/min and 57% at 5.5 ml/min. There was a similar increase in dF/dt. The increase in developed force in the first minute was also dose-dependent, being 9% at 0.55 ml/min and 40% at 5.5 ml/min. No change in developed force occurred in the control (non-perfused) area or during saline infusion of the same artery at similar rates. A decrease in developed force of 10.5% was observed after the initial rise when mannitol was infused at 5.5 ml/min. This effect did not completely abolish the initial increase. No change in blood pressure, heart rate, LV systolic and diastolic pressure of LV dp/dt occurred during the experiment. It is concluded that doses of mannitol which are in clinical use have a direct positive inotropic effect on the intact canine heart.

Animals↗
PubMedDate not supplied

Prevention of myocardial depression in experimental hemorrhagic shock by pretreatment with hydrocortisone.

The left anterior descending or left circumflex coronary artery was cannulated in ten dogs. 4 mg/kg hydrocortisone were slowly infused and the cannula was withdrawn. The dogs were then subjected to hemorrhagic shock for 90 minutes followed by retransfusion. The contractile force (CF) and its first derivative (df/dt) were measured in the pretreated (infused) area and in a control (non-perfused) area of the left ventricle. During the shock period, CF and df/dt in the non-pretreated area showed a 50% reduction in comparison to the pre-shock level, whereas the contractile force in the area that had been pretreated with hydrocortisone did not change when compared to the pre-shock period. This study shows that myocardial depression secondary to hemorrhagic shock can be effectively prevented by pretreatment with hydrocortisone.

Animals↗
PubMedDate not supplied

Mitral valve replacement in patients after aortic valve replacement.

BACKGROUND: Mitral valve replacement in patients who previously had undergone aortic valve replacement is a technical challenge. The rigid aortic prosthesis limits visualization of the anterior mitral annulus and placement of sutures. METHODS: Reoperative mitral valve replacement was performed in five patients after aortic valve replacement. Two patients underwent resternotomy to allow verification of normal aortic prosthetic valve function. Anterolateral right thoracotomy was used for reentry in the remaining three patients. Exposure of the anterior mitral annulus was accomplished by initial traction on the intact anterior leaflet, with resection of this leaflet only after placement of sutures. RESULTS: All patients survived the surgical procedure and are well 2 to 30 months after operation. In one patient it was impossible to open one cusp of the mitral prosthesis, nor was it possible to rotate the valve. The valve was reimplanted, but sutures were tied only after testing for full free cusp motion. CONCLUSIONS: When appropriate, right thoracotomy incision offers excellent exposure of the mitral valve with minimal dissection. Placement of sutures along the anterior portion of the annulus is facilitated by traction downwards on the anterior leaflet. Full range of motion of the prosthetic cusps should be verified before tying the sutures.

Aged↗
PubMedDate not supplied

Surgery for tricuspid valve disease.

Sixty patients underwent repair or replacement of the tricuspid valve, 58 for acquired and two for congenital lesions. In 59 of the cases, the tricuspid surgery formed part of multiple valve surgery. Preoperatively, 33 patients (55%) were in New York Heart Association class IV and 25 in class III functional capacity. The tricuspid valve was replaced in 42 patients and repaired in 18. Forty-seven patients (78%) survived operation, but 10 of these died during a follow-up period of two to seven years. Thirty-four of the 37 long-term survivors show marked improvement. Operative mortality was 26% for tricuspid valve replacement and 11% for repair; late mortality was 14% and 22%, respectively. It should be stressed that the tricuspid valve replacement group consisted of patients whose preoperative condition was worse and whose valvular pathology was more severe than that of those who had tricuspid repair. In view of this, and the better long-term results of tricuspid valve replacement, it is concluded that the procedure of choice for serious organic disease of the tricuspid valve is valve replacement.

Adolescent↗
PubMedDate not supplied

Surgical treatment of post-infarction ventricular septal defect without concomitant myocardial revascularization.

Twenty one patients suffering from rupture of the ventricular septum (RVS) following acute myocardial infarction were operated upon between 1982-1985. Eighteen patients were operated upon urgently within 9.3 +/- 2.1 hours following diagnosis of RVS. In all, RVS occurred during the first infarction. None had concomitant myocardial revascularization. There were twelve operative survivors for an operative mortality of 42.5%. Two patients died 6 and 9 months postoperatively. All survivors are in functional class I, during a follow-up period of 14 to 56 months. The need for urgent repair of RVS is stressed and the value of concomitant coronary artery bypass is discussed.

Aged↗
PubMedDate not supplied

Surgery for rheumatic tricuspid valve disease in children.

Rheumatic valvular disease in children is common in underprivileged countries and often damages the tricuspid valve (in addition to the mitral and aortic valves). Fifteen children aged 12 to 16 years underwent tricuspid valve surgery. Fourteen were graded as Class IV disability; five were operated during rheumatic activity. The tricuspid valve was replaced in ten patients, four had annuloplastic procedures and one underwent tricuspid commissurotomy. There was one operative death and four late deaths. Eight of the ten long-term survivors are in Class I and the remainder in Class II functional ability. It may be concluded that in children who can be protected from additional bouts of carditis and thromboembolism, the surgical treatment of advanced multivalvular disease including the tricuspid valve is most rewarding, and dramatic clinical improvement with return to normal or near-normal hemodynamics may be expected.

Adolescent↗