Prevention of Venous Thrombosis by Warfarin after Permanent Transvenous Leads Implantation in High-Risk Patients

Background: The incidence of venous lesions following transvenous cardiac device implantation is high. Previous implantation of temporary leads ipsilateral to the permanent devices, and a depressed left ventricular ejection fraction have been associated with an increased risk of venous lesions, though the effects of preventive strategies remain controversial. This randomized trial examined the effects of warfarin in the prevention of these complications in high-risk patients.
Method: Between February 2004 and September 2007, we studied 101 adults who underwent a first cardiac device implantation, and who had a left ventricular ejection fraction ≤0.40, or a temporary pacing system ipsilateral to the permanent implant, or both. After device implantation, the patients were randomly assigned to warfarin to a target international normalized ratio of 2.0–3.5, or to placebo. Clinical and laboratory evaluations were performed regularly up to 6 months postimplant. Venous lesions were detected at 6 months by digital subtraction venography.
Results: Venous obstructions of various degrees were observed in 46 of the 92 patients (50.0%) who underwent venography. The frequency of venous obstructions was 60.4% in the placebo, versus 38.6% in the warfarin group (P = 0.018), corresponding to an absolute risk reduction of 22% (relative risk = 0.63; 95% confidence interval = 0.013–0.42).
Conclusions: Warfarin prophylaxis lowered the frequency of venous lesions after transvenous devices implantation in high-risk patients.     

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.     

Pacing Rate Increase as Cause of Syncope in a Patient with Severe Cardiomyopathy

Hemodynamic deterioration occurs with ventricular pacing rate increase in the presence of severe chagasic cardiomyopathy. Syncope and orthopnea occurred during ventricular pacemaker evaluation when the pacing rate was temporarily increased by magnet application. Cardiac output decreased by 54%, the arterial blood pressure by 38%. and the pulmonary wedge pressure increased by 54%. Such severe myocardial compromise may limit the use of rate modulated pacemakers.