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J Thorac Cardiovasc Surg 1999;117:831-832
© 1999 Mosby, Inc.
BRIEF COMMUNICATIONS |
From the Cardiovascular Research/Care Foundation, Phoenix, Ariz.
Received for publication Nov 16, 1998. Accepted for publication Dec 2, 1998. Address for reprints: Neil J. Thomas, MD, Cardiovascular Research/ Care Foundation, 2720 North 20th St, Suite 440, Phoenix, AZ 85006. E-mail: njtcvsg{at}abilnet.com
Refractory or recurrent episodes of sustained ventricular tachycardia are a potentially life-threatening complication of acute myocardial infarction and of various forms of cardiomyopathy. In either setting, increased ventricular wall tension may exacerbate acute or chronic ischemia and the resultant milieu can lead to sudden death. Mechanical circulatory assistance is effective in improving survival for patients with overt pump failure, as a "bridge to transplantation." On the basis of recent reports, modern implantable systems may also be effective in extinguishing ventricular arrhythmias and successfully bridging such patients to transplantation.
1 We report a case of an acute postoperative myocardial infarction and medically refractory ventricular tachycardia in which insertion of a left ventricular assist device (LVAD) successfully extinguished the arrhythmia and allowed the patient to recover satisfactorily without transplantation.
Clinical summary
A 41-year-old man with normal ventricular function was referred for coronary artery bypass grafting. He underwent uneventful bypass grafting of the left anterior descending coronary artery and the obtuse marginal branch. Thirty minutes later, he had acute vein graft occlusion and signs of acute ischemia in the lateral precordial leads. He was returned to the operating room immediately for revision of the circumflex graft. No technical problem was identified, but the graft was redone. The patient was found subsequently to have a hypercoagulable state, characterized by inherited protein-S deficiency and hyperreactive platelets, even while he was receiving aspirin (Sonoclot; HEMEX LABS, Phoenix, Ariz).
He had several episodes of sustained and medically refractory ventricular tachycardia associated with complete circulatory collapse. Ventricular countershocks and treatment with high-dose magnesium sulfate and intravenous amiodarone terminated each episode, and the patient remained in neurologically intact condition. During periods of sinus rhythm, hemodynamics were satisfactory (cardiac index > 2.5 L/min per square meter) on minimal doses of inotropic agents. The electrocardiogram did not show a recurrence of changes suggesting reocclusion of the graft. The third overt cardiac arrest, which was more difficult to terminate, prompted the initiation of left ventricular support with the ABIOMED BVS-5000 LVAD (Abiomed, Inc, Danvers, Mass). LVAD flows were approximately 4.5 L/min and bleeding after insertion was minimal. Ventricular tachycardia was completely extinguished and premature ventricular complexes all but disappeared. He awoke 12 hours after the operation in neurologically intact condition.
Multiorgan system dysfunction resolved over the next 2 weeks. He was able to ambulate in his room while being supported by the LVAD, but on support day 22 moderately severe left hemiparesis developed, and he required an additional 9 days of mechanical ventilatory support because of adult respiratory distress syndrome. The neurologic deficit slowly resolved and support was discontinued after 27 days with no recurrence of ventricular tachycardia and no signs or symptoms of cardiac failure. A follow-up echocardiogram showed a left ventricular ejection fraction of 45% to 50%. In addition, 4 months later he was able to ambulate with a cane and perform activities of daily living.
Discussion
In this report, we describe a situation in which LVAD insertion was prompted by recurrent ventricular tachycardia and resultant circulatory collapse in a patient without evidence of overt left ventricular pump failure. The arrhythmia was completely eradicated, and we are aware of no similar, previously reported case of "bridging to recovery" in the postcardiotomy setting. Medical therapy was ineffective and no evidence of active, correctable ischemia was present. Satisfactory ventricular unloading and circulatory support circumvented the threat of sudden death and was lifesaving. The infarction-related irritable focus was given an opportunity to heal. We also realize that direct apical cannulation, chosen to maximize drainage, may have obliterated the focus and eradicated the arrhythmia. In either case, our experience represents an expanded application of intermediate-term LVAD support.
Early LVADs were inserted into patients with profound circulatory failure and were intended for brief periods of support in the postcardiotomy setting. The recent experience with advanced, but prototypical, long-term implantable LVADs has shown their efficacy in improving end-organ function and survival in patients in the "bridge-to-transplantation" setting. 2 The organization of the REMATCH trial, a Food and Drug Administration–approved study of mechanical support as "destination therapy," 3 and the Berlin experience 4 suggest that the indications for the insertion of such systems have expanded. The report by Muller and associates 4 suggests that some patients with end-stage cardiomyopathy may be bridged to recovery. Acceptance of this idea requires a conceptual paradigm shift from that of the early implementation of temporary, centrifugal, short-term support devices. The concept of "destination" or permanent therapy, rather than insertion with the intention of "bridging to transplantation," could be viewed as a maturation or evolution of the use of these devices. This evolution is a result of advances in technology, experience, and surgical expertise. However, the German report, in particular, 4 brings to light the increasingly widespread realization that mechanical unloading of the failing, ischemic, or stunned ventricle for a variable length of time may lead to recovery of the heart. 5 Similarly, our report suggests that patients with acute, infarction-related refractory arrhythmias and concomitant circulatory collapse may benefit from intermediate-term ventricular unloading and circulatory support, even in the absence of overt pump failure. This case, in particular, illustrates the way in which such support, when implemented in a timely fashion, may avert life-threatening multiorgan system failure. We believe this experience demonstrates the benefit of an aggressive surgical posture and a commitment to vigilance with respect to the early initiation of support in an expanded patient population.
Acknowledgments
We acknowledge the assistance of the cardiac surgery service, University Medical Center, Tucson, Arizona, in caring for this patient.
References
This article has been cited by other articles:
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  L. Zhang, E. I. Kapetanakis, R. H. Cooke, L. C. Sweet, and S. W. Boyce Bi-Ventricular Circulatory Support With the Abiomed AB5000 System in a Patient With Idiopathic Refractory Ventricular Fibrillation Ann. Thorac. Surg., January 1, 2007; 83(1): 298 - 300. [Abstract] [Full Text] [PDF]
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 O. Ziv, J. Dizon, A. Thosani, Y. Naka, A. R. Magnano, and H. Garan Effects of Left Ventricular Assist Device Therapy on Ventricular Arrhythmias J. Am. Coll. Cardiol., May 3, 2005; 45(9): 1428 - 1434. [Abstract] [Full Text] [PDF]
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L. E. Samuels, E. C. Holmes, M. P. Thomas, J. C. Entwistle III, R. J. Morris, J. Narula, and A. S. Wechsler Management of acute cardiac failure with mechanical assist: experience with the ABIOMED BVS 5000 Ann. Thorac. Surg., March 1, 2001; 71 (2007): S67 - S72. [Abstract] [Full Text] [PDF]
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