Comparison of pre- and postoperative conduction patterns in patients surgically cured of atrioventricular node reentrant tachycardia.

Patients with atrioventricular (AV) node reentrant tachycardia characteristically have short and constant retrograde His-atrium conduction times (H2A2 intervals) during the introduction of ventricular extrastimuli. It has therefore been suggested that the tachycardia circuit involves retrograde conduction up an accessory pathway located in perinodal tissue. If the mechanism of surgical cure of AV node reentrant tachycardia is interruption of this accessory pathway, postoperative changes in retrograde conduction would be expected. Thirteen patients with drug-refractory AV node reentrant tachycardia underwent surgery. Preoperatively, H2A2 intervals were short and constant. During AV node reentrant tachycardia, earliest atrial activation was seen near the His bundle and was 0 to 25 ms before ventricular activation in all patients except one. Surgery consisted of dissection of right atrial septal and anterior inputs to the AV node and central fibrous body. Postoperatively, the H2A2 interval remained short and constant compared with preoperative values although it was slightly prolonged (74 +/- 18 versus 61 +/- 21 ms, p less than 0.005). Twelve of the 13 patients are free of tachycardia after 28 +/- 13 months and no patient has had evidence of AV node block. Thus, surgical cure of AV node reentrant tachycardia is highly successful; however, there is no reason to postulate an accessory pathway or use of perinodal tissue as part of the tachycardia circuit and the mechanism of surgical success remains obscure.

Long-term outcome with the automatic implantable cardioverter-defibrillator.

The automatic implantable cardioverter-defibrillator was implanted in 270 patients because of life-threatening arrhythmias over a 7 year period. There was a history of sustained ventricular tachycardia or fibrillation, or both, in 96% of these patients, 80% had one or more prior cardiac arrests and 78% had coronary artery disease as their underlying diagnosis. The average ejection fraction was 34%, and 96% of these patients had had an average of 3.4 antiarrhythmic drug failures per patient before defibrillator implantation. There were four perioperative deaths and eight patients had generator infection or generator erosion, or both, during the perioperative period or during long-term follow-up. Concomitant antiarrhythmic drug therapy was given to 69% of patients. Shocks from the device were given to 58% of patients. and 20% received "problematic" shocks. The device was removed from 16 patients during long-term follow-up for a variety of reasons. There were 7 sudden cardiac deaths and 30 nonsudden cardiac deaths, 18 of which were secondary to congestive heart failure. The actuarial incidence of sudden death, total cardiac death and total mortality from all causes was 1%, 7% and 8%, respectively, at 1 year, and 4%, 24% and 26% at 5 years. The automatic implantable cardioverter-defibrillator nearly eliminates sudden death over a long-term follow-up period in a high risk group of patients. It has an acceptable rate of complications or problems, or both, and most late deaths in these patients are nonsudden and of cardiovascular origin.

Comparison of defibrillation efficacy in humans using a new catheter and superior vena cava spring-left ventricular patch electrodes.

The automatic implantable cardioverter-defibrillator currently utilizes an electrode system that requires a major operation for implantation. Effective defibrillation using an implantable cardioverter-defibrillator catheter positioned transvenously would eliminate the morbidity associated with such surgery. Fifteen patients undergoing defibrillator implantation were studied to compare the efficacy of the catheter with that of the superior vena cava spring (6.7 cm2, anode)-left ventricular patch (13.5 cm2, cathode) electrode system using truncated exponential waveforms with 60% tilt. The catheter is 11F in diameter and tripolar. A distal platinum-iridium tip used for pacing was separated by 4 mm from a middle 4.3 cm2 platinum electrode; these were positioned at the right ventricular apex. The proximal 8.5 cm2 platinum electrode was situated at the superior vena cava-right atrial junction. Defibrillation was performed using the middle (cathode) and proximal (anode) electrodes. Ventricular fibrillation was induced by alternating current six times, and defibrillation shocks of 1, 5, 10, 15, 20 or 25 J were given in random order, first using the catheter and then the spring-patch system. Rescue shocks of higher energy were given if there was failure. Although very low energy levels appeared to be slightly more efficacious when using the spring-patch system, there was no statistically significant difference between the electrode systems for any of the energies tested. Permanent implantation of the catheter would have been suitable in 45% of the patients, as compared with 54% of patients with the spring-patch system (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in regional contractility following cardiopulmonary bypass with intraoperative ischemia.

Coronary occlusion during cardiopulmonary bypass has been used in place of aortic occlusion to perform coronary artery anastomoses, but this procedure on distal myocardial function has not been evaluated. Regional myocardial function was examined with the use of ultrasonic crystals in 20 dogs subjected to this technique to compare normothermic and hypothermic (30 degrees C) bypass in both beating and fibrillating hearts. We found a significant decline in the velocity of contraction of the distal segment in fibrillating compared to bearing hearts (p less than 0.01). Hypothermia prevented this decline in the beating, but not the fibrillating, hearts. With respect to contractile function in the distal myocardial segment, local occlusion techniques cause an injury similar to that reported for aortic cross-clamping.

Continuous epicardial echocardiographic assessment of postoperative left ventricular function.

An ultrasound transducer which is sutured to the heart at operation and removal percutaneously has been developed and tested in 20 animals. The potential of this device to monitor cardiac function was measured by simultaneously recording 67 left ventricular angiograms and echograms over a wide range of hemodynamic function. In addition, the reproducibility of the data obtained from the transducer and the safety of application and withdrawal were examined. We found highly significant (p less than 0.005) linear correlation between echocardiographic and angiographic measurements of left ventricular end-diastolic volume, end-systolic volume, and ejection fraction. This transducer may provide the means to assess left ventricular size and ejection fraction continuously after cardiac operations in man.

Operative treatment of an unresectable tumor of the left ventricle.

A 17-year-old girl presented with an enlarged cardiac silhouette on routine chest roentgenogram. After clinical evaluation, echocardiography, and pericardiocentesis failed to provide a diagnosis, exploratory thoracotomy and biopsy revealed an unresectable left ventricular fibroma. The tumor continued to enlarge and began causing ventricular arrhythmia. Therefore, she underwent cardiac transplantation 2 years after the initial diagnosis was made. She is now alive nd well 18 months following transplantation.

Diagnosis and treatment of allograft rejection in heart-lung transplant recipients.

Six patients received heart-lung transplants between March, 1981, and January, 1982. There were four women and two men between 26 and 45 years of age, three with primary pulmonary hypertension and three with congenital heart disease and pulmonary hypertension (Eisenmenger's syndrome). Immunosuppression was primarily with cyclosporin-A, with additional corticosteroid, azathioprine, and rabbit antihuman thymocyte globulin. Six episodes of allograft rejection in four patients (10, 11, 21, 24, 53, and 86 days after transplantation) were detected by means of transvenous endomyocardial biopsy. All patients experienced pulmonary edema early after transplantation (reimplantation response), and two patients required mechanical ventilatory support for allograft rejection at 10 and 11 days. Treatment of rejection consisted of intravenous methylprednisolone (four episodes) or augmented oral prednisone (two episodes), with resolution. No episode thought to be pulmonary rejection has occurred in the absence of cardiac findings. Four patients are alive from 6 to 15 months after transplantation and are functionally normal. Early experience with heart-lung transplantation suggests (1) that allograft rejection can be detected by cardiac findings and successfully treated by augmented corticosteroids, (2) that lung rejection does not occur in the absence of cardiac findings, (3) that the frequency and severity of rejection episodes are not greater than with standard cardiac transplantation, and (4) that the frequency of rejection episodes is highest within the first 60 days after transplantation.

Postinfarction ventricular septal defect: an argument for early operation.

We reviewed our experience with 43 consecutive patients who underwent operations for postinfarction ventricular septal defect to determine optimal time for operative intervention, to identify factors responsible for failure of operative treatment, and to determine long-term survival rates. Patients were referred for operation after expectant medical management had failed or after 6 weeks electively. The operative mortality rate was 42% and ranged from 90% for those who required operation within 1 day of 11% for those underwent surgery after 1 month. In a multivariate discriminant analysis of preoperative variables, we found that inferior infarction with perforation (P less than 0.02) and preoperative multisystem failure (evidenced by abnormal mental status, P less than 0.02) were the major factors correlating with high operative risk. Early operation per se did not affect operative mortality rates. Technical problems with early operation were not a source of major morbidity and mortality. Actuarial long-term survival was good, and 88.5% of survivors were alive 5 years after surgery. Because preoperative multisystem failure is often progressive, we recommend immediate operation for all patients with postinfarction ventricular septal defect unless no deterioration is present. Moreover, because of the high risk of those patients with inferior infarction and perforation, we recommended immediate surgery for this group regardless of symptomatic status.

Left main coronary artery reconstruction after radiation therapy.

We report the case of a patient with radiation-induced left main coronary stenosis in whom an internal mammary artery bypass graft failed a 5 years and necessitated direct left main reconstruction.

"Legs" technique for management of widely separated coronary arteries during ascending aortic repair.

BACKGROUND: Widely separated coronary arteries with significantly diseased tissue continues to challenge surgeons repairing ascending aortic aneurysms. METHODS: Occasional troublesome leaks around coronary ostial anastomoses and Cabrol graft thrombosis prompted a change of our operative management of this condition. Collagen-impregnated 8-mm "legs" grafts are used to connect the coronary arteries to the composite graft. Ten patients, aged 14 to 70 years, underwent the operation. RESULTS: The first patient is 15 years after the operation and is symptom free. One patient died of an arrhythmia 1 month after discharge. Eight patients are living and well 11/2 to 4 years postoperatively. CONCLUSIONS: Advantages of direct interposition (legs) grafts are as follows: the coronary arteries are separately perfused and the risk of catastrophic thrombosis from a longer high-volume graft is eliminated. Problems with coronary ostial mobilization are avoided. The technique allows full visualization and hemostatic suture line testing with cardioplegia before aortic declamping. Space constraints with reoperations are easily managed, whereas other techniques may result in graft compression on refilling of the heart and termination of bypass. The technique is carried out with ease and reproducibility, and the availability of new graft material has made it our treatment of choice for ascending aortic composite graft replacement.

Limits of myocardial protection with potassium cardioplegia.

Preservation of left ventricular function with various potassium-based cardioplegic solutions has been considered to be effective for at least 60 minutes during occlusion of the ascending aorta. The purpose of this study was to define the limits of protection offered by potassium alone. A single bolus of 150 ml of potassium (24 mEq per liter) in normal saline solution at 30 degrees C was injected in the aortic roots of foxhounds at the initiation of periods of 45 minutes, 60 minutes, and 75 minutes of aortic occlusion at a core temperature of 30 degrees C. Data derived from postischemic recovery phase ventricular function curves and force-velocity relations demonstrated excellent protection during 45 minutes of ischemia, inconsistent protection at 60 minutes, and poor protection at 75 minutes.

Cardiac tamponade.

Cardiac tamponade is an insidious and often fatal complication which can occur on any service, in many diseases, and at any age. The increasing pressure within the pericardium prevents ventricular filling and depresses cardiac output, coronary and systemic perfusion, and venous return. Compensatory mechanisms may protect the patient for some time, but prompt diagnosis and rapid decompression are usually required and must be followed by meticulous evaluation and treatment of the underlying disease.

A biologically compatible implantable ultrasonic marker.

An implantable passive ultrasonic marker has been developed which can be detected with a conventional pulse echo imaging system. The marker consists of a planar array of 1/16 in. diameter stainless steel (316L) spheres and produces a distinct and characteristic reflection signature due to reverbation within the spheres. The marker has undergone both in vitro and in vivo tests and is biologically compatible for chronic implantation. It is consistently detectable at depths up to 10 cm from the transducer. An application to the detection of flow conditions in aortocoronary bypass grafts is suggested.

Method for cardiac transplantation in corrected transposition of the great arteries.

A patient with corrected transposition of the great vessels (L-transposition) required cardiac transplantation because of severe myopathy of th systemic ventricle of right ventricular morphology. Because of the L-transposition of the great vessels, a modification of the transplantation procedure was necessary in order to make the great vessel anastomoses. This was accomplished without the need for prosthetic material primarily by extensive removal of donor pulmonary artery and aorta together with the heart. Anastomosis of the recipient ascending aorta was accomplished to the superior aspect of the transverse aortic arch of the donor, and the recipient pulmonary artery to the superior portion of the right pulmonary artery of the donor. The postoperative hemodynamics were normal and a thoracic aortogram one year post-transplant demonstrated the unusual anatomy.

Veno-venous allografts: patency, subendothelial proliferation, and the role of platelet-active agents.

Patency and histology of 81 vein allografts and 10 autografts in the canine femoral venous system were compared and the effect of platelet active agents in altering patency rates and subendothelial proliferation in allografts was examined. It was found that allografts thrombose at a predictable interval after operation (18 +/- 7 days) and have significantly worse survival than autografts (P less than 0.001). Platelet-active agents did not alter allograft patency rate of the incidence of subendothelial proliferation in this model.

Intraoperative, intracardiac echocardiography during left ventriculomyotomy and myectomy for hypertrophic subaortic stenosis.

In 15 patients undergoing left ventriculomyotomy and myectomy for idiopathic hypertrophic subaortic stenosis (IHSS), the thickness of the interventricular septum was measured before and after muscle resection by means of a modified sternal-notch pediatric ultrasound transducer. Preoperative and intraoperative measurements by echogram were highly correlated (r = 0.92, P = 0.6), and accurately predicted the dimensions of the excised bar of muscle (r = 0.98, P = 0.6). The mean depth of the trough created at operation was 9.7 +/- 0.8 mm, and the mean thickness of the septum remaining was 14.3 +/- 0.9 mm. When studied 6 months postoperatively, all surviving patients were functionally improved, and none had a pressure gradient when studied in the resting state. However, two-thirds of the patients had residual provocable gradients (decreased by 70% from those preoperatively). Intraoperative echogram measurements failed to correlate with the presence or extent of the postoperative provocable gradients. Intraoperative echocardiography provides imaging of dimensions otherwise unavailable, and may help define the characteristics of the myectomy that result in uniform symptomatic and hemodynamic benefit.