New-onset sustained ventricular tachycardia and fibrillation early after cardiac operations

BACKGROUND: Malignant ventricular tachyarrhythmia early after cardiac surgery is an uncommon arrhythmic complication but has a negative impact on mortality. The purpose of this study was to evaluate the incidence of new-onset sustained postoperative ventricular tachycardia-ventricular fibrillation and to identify risk factors for the dysrhythmia. METHODS: Demographic, clinical, operative, and postoperative data, including a variable of postoperative ventricular tachycardia, were prospectively obtained from 4748 patients undergoing nonemergency coronary artery bypass graft and(or) valve replacement with no history of sustained ventricular tachycardia or sudden death. A detailed analysis was performed to define the risk factors for the ventricular tachycardia and the prognostic impact of the arrhythmia on 30-day mortality was evaluated. RESULTS: Forty-five patients (0.95%) had sustained ventricular tachycardia or ventricular fibrillation and the initial episode occurred 3.9 +/- 5.2 days (mean +/- standard deviation) after surgery. By multivariate analysis, female sex (odds ratio, 1.982), left ventricular ejection fraction (< 35%: > 50%, 4.771), the presence of pulmonary hypertension (3.066), the presence of systemic hypertension (2.391), and pump time (per 10 minutes, 1.085) were independently associated with the dysrhythmias. Early mortality of patients with the arrhythmia was 28.9%, strikingly higher than that of patients without ventricular tachycardia/ventricular fibrillation (1.9%). CONCLUSIONS: Left ventricular ejection fraction is the strongest risk factor for new-onset postoperative sustained ventricular tachycardia-ventricular fibrillation; female sex, pump time, pulmonary and systemic hypertension are independent predictors of the dysrhythmias; the arrhythmia is associated with increased 30-day mortality after cardiac surgery.     

Thrombolytic therapy.

Thrombolytic therapy may be used as either sole treatment or an adjunct to surgery in both arterial and venous disease. The age of the clot, particularly with venous thrombosis, determines the probability of successful lysis, with recent clot being highly susceptible to lytic therapy. The technique of thrombolysis is also an important determinant of the outcome, with high doses delivered directly into the clot over short time periods associated with the highest success and the lowest complication rates. Because systemic therapy increases the risk of bleeding from a remote site, techniques to concentrate the lytic agent within the clot, such as intraoperative high-dose and isolated-limb therapy, may achieve a higher success with a lower complication rate. Newer agents, which are clot specific, will be available for lytic therapy and should result in even higher success rates while minimizing systemic complications.     

Left ventricular assist device (LVAD) enables survival during 7 h of sustained ventricular fibrillation.

We describe the case of a patient implanted with a DeBakey left ventricular assist device (LVAD) as bridge to transplant who survived 7 h of ventricular fibrillation. He was successfully converted into a stable sinus rhythm.     

Thrombolytic therapy in acute arterial thrombosis

The courses of 17 patients who underwent 20 separate attempts at thrombolysis for acute arterial thrombosis are reviewed to clarify the safety and efficacy of this therapy. Seventeen of 20 thrombolyses were angiographically successful. Patients who had correctable lesions identified and reconstructive procedures performed tended to do better than those who did not, and patients who had successful thrombolysis tended to have fewer and less radical amputations. Complications can be reduced by careful, close monitoring of patients undergoing therapy.     

Thrombolytic therapy in an isolated limb

Intraoperative thrombolytic therapy is a useful adjunct to balloon catheter thromboembolectomy for treatment of acute embolism or thrombosis, but the technique is frequently limited by incomplete thrombolysis and systemic hemorrhage. In an attempt to improve results and reduce complications of conventional thrombolytic therapy, urokinase was infused into a limb that was isolated with a tourniquet. This isolated limb perfusion technique was initially developed in an animal model and subsequently used for limb salvage in patients who failed thromboembolectomy. The animal model demonstrated that a fibrinolytic state could be achieved and isolated to the extremity, even when using extremely high doses (20,000 to 50,000 IU/kg) of thrombolytic agents. The fibrinogen level was unmeasurable and the prothrombin, partial thromboplastin, and thrombin times were significantly prolonged in the isolated limb (p < 0.001), whereas no changes occurred in these parameters in the systemic circulation. In seven patients, streptokinase (27,000 to 200,000 IU) and urokinase (150,000 to 300,000 IU) were infused into isolated extremities after thrombectomy alone had failed to restore blood flow. All extremities showed improved perfusion after thrombolytic therapy and five remained viable 6 months after treatment. There were no systemic bleeding complications despite two patients having undergone major operations within 6 days. Tourniquet isolation of the limb can achieve extremely high concentrations of thrombolytic drugs while reducing the potential for systemic fibrinolysis and allows lysis of previously inaccessible thrombus.     

Thrombolytic therapy during cardiopulmonary resuscitation

Recently, efforts have been undertaken to investigate the effects of thrombolysis during cardiopulmonary resuscitation (CRP) in patients suffering from massive pulmonary embolism or acute myocardial infarction. In up to 70% of patients with cardiac arrest, one of these two diseases is the underlying cause of deterioration. Nevertheless, thrombolysis has not been conducted during CPR because of the fear of severe bleeding complications. However, an increasing number of clinical studies suggest that thrombolytic therapy during CPR can contribute to haemodynamic stabilisation and survival in patients with massive pulmonary embolism and acute myocardial infarction, when conventional CPR procedures have been performed unsuccessfully. Apart from the specific causal action of thrombolytic agents at the site of pulmonary emboli and coronary thrombosis, experimental data indicate that thrombolysis during CPR can improve microcirculatory reperfusion, which may be most important in the brain. In accordance with these data, marked activation of blood coagulation without adequate activation of endogenous fibrinolysis has been demonstrated early after cardiac arrest. In summary, thrombolysis during CPR is presently a treatment strategy that can be performed on an individual basis in patients with pulmonary embolism or acute myocardial infarction. It may become a routine measure if positive results of randomised, controlled clinical trials will be available in the future.     

Thrombolytic therapy of axillary-subclavian venous thrombosis

Patients with axillary-subclavian vein thrombosis often have a poor outcome when treated with intravenous heparin sodium and oral warfarin sodium. Four patients were therefore treated with thrombolytic therapy. Good initial and excellent long-term results were achieved. In follow-up that has ranged up to four years, these patients do not have the common complaints of edema, fatigue, cramping, or weakness seen after traditional anticoagulation. Patients have returned to their previous occupations and have normal arm function. Noninvasive Doppler vascular laboratory studies suggest continued patency of axillary veins. Thrombolytic therapy should be considered in the treatment of spontaneous axillary-subclavian vein thrombosis.     

Thrombolytic therapy for pulmonary embolism.

Consensus regarding the use of thrombolysis to treat acute pulmonary embolism has not yet been reached. There is good evidence that thrombolytic agents dissolve clot more rapidly than heparin. However, proving that this benefit reduces the death rate from pulmonary embolism has been difficult. Each of the 3 thrombolytic agents (tissue type-plasminogen activator, streptokinase and urokinase) is equally efficacious at dissolving clot, but all are associated with an increased risk of major hemorrhage when compared with heparin. One evolving position is that, in addition to patients presenting in circulatory collapse, for whom thrombolysis has been demonstrated to be life-saving, a subgroup of patients may be identified by echocardiography, through its ability to assess right ventricular dysfunction, who should also be considered for thrombolytic therapy. It remains to be seen whether this approach can reduce the death rate associated with pulmonary embolism.     

Thrombolytic therapy for acute arterial occlusion

To evaluate the role of selective intra-arterial low-dose thrombolytic therapy (SILDT) as an alternative to the surgical management of acute arterial occlusion, the hospital records of 40 patients who underwent 43 SILDT treatments with either streptokinase (36) or urokinase (7) between December 1979 and March 1984 were reviewed. Twenty-eight patients underwent 30 treatments (group 1) for native arterial occlusion and 12 patients underwent 13 treatments (group 2) for prosthetic or autogenous graft occlusions. Therapy was deemed successful if subsequent surgical therapy was obviated. In group 1, SILDT was successful in 13 of 28 (45%) patients with 12 of 25 lower extremity occlusions and one of three upper extremity occlusions. Successful lysis in the native artery occlusion group fell into three categories: five patients were successfully treated for arterial thrombosis complicating percutaneous transluminal angioplasty (PTA); four patients required PTA after complete lysis revealed an underlying arterial stenosis; and only three required no further therapy after SILDT. SILDT failed in all three patients with the aortoiliac occlusions. Eleven patients with femoral artery occlusions and unsuccessful SILDT required six bypass procedures, three amputations, one embolectomy, and one PTA. In group 2 only 3 of 14 treatments (21%) were successful. Bypass revision was not possible in 11 patients and all required amputation. Systemic fibrinolysis was seen in 20 (59%) of 34 patients with available data. Neither fibrinogen levels nor fibrin degradation products predicted the occurrence of complications. Minor complications occurred in 18 of 43 (43%) treatments; small hematomas at the catheter entry site were most common. Minor complications occurred in 20 of 43 treatments (44%) and included severe local hemorrhage (four), distant bleeding (three), pulmonary embolism (four), myocardial infarction (three), unmasking of an aortoduodenal fistula (one), and clot migration requiring emergency thrombectomy (four). SILDT is most effective in acute arterial thrombosis complicating arteriography or percutaneous angioplasty. It may play a role in the patient in whom thrombolysis can reveal an underlying stenosis amenable to percutaneous angioplasty. This experience shows SILDT to be of limited value in the management of prosthetic autogenous graft occlusions. Finally, thrombolytic therapy is associated with significant morbidity and mortality rates and requires cautious monitoring to detect arterial thrombus migration, worsening tissue ischemia, venous thromboembolism, intracerebral hemorrhage, and local or systemic bleeding.