Surgical Treatment of Ischemic Dilative Cardiomyopathy by Ventricular Restoration.

Patients with symptomatic post-ischemic dilative myocardiopathy of the left ventricle require, in selected cases, an operation to reshape and reduce the volume of the left ventricular chamber, in addition to surgical myocardial revascularization and mitral valve repair, with the aim of prolonging survival, improving the quality of life and minimizing the need for re-hospitalizations related to recurrent heart failure. This procedure is called surgical ventricular restoration (SVR), and is a useful tool for the treatment of heart failure patients as an alternative to heart transplant. This article provides an overview of surgical ventricular restoration for the treatment of dilative ischemic myocardiopathy. It illustrates several surgical options, describes the operative details, and discusses the correct indications for the procedure. Finally, an interesting protocol for one-step cell therapy during SVR is proposed, as an innovative treatment for heart failure patients.

Simvastatin reduces the TLR4-induced inflammatory response in human aortic valve interstitial cells.

BACKGROUND: Calcific aortic stenosis is a chronic inflammatory disease. Proinflammatory stimulation via toll-like receptor 4 (TLR4) causes the aortic valve interstitial cell (AVIC) to undergo phenotypic change. The AVIC first assumes an inflammatory phenotype characterized by the production of inflammatory mediators such as intercellular adhesion molecule-1 (ICAM-1), interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1). This change has been linked with an osteogenic phenotypic response. Statins have recently been shown to have anti-inflammatory properties. We therefore hypothesized that statins may have an anti-inflammatory effect on human AVICs by downregulation of TLR4-stimulated inflammatory responses. Our purposes were (1) to determine the effect of simvastatin on TLR4-induced expression of inflammatory mediators in human AVICs and (2) to determine the mechanism(s) through which simvastatin exert this effect. MATERIALS AND METHODS: Human AVICs were isolated from the explanted hearts of four patients undergoing cardiac transplantation. Cells were treated with simvastatin (50 µM) for 1 h before stimulation with TLR4 agonist lipopolysaccharide (LPS, 0.2 µg/mL). Immunoblotting (IB) was used to analyze cell lysates for ICAM-1 expression, and enzyme-linked immunosorbent assay was used to detect IL-8 and MCP-1 in cell culture media. Likewise, lysates were analyzed for TLR4 and nuclear factor-kappa B activation (IB). After simvastatin treatment, lysates were analyzed for TLR4 levels (IB). Statistics were by analysis of variance (P < 0.05). RESULTS: Simvastatin reduced TLR4-induced ICAM-1, IL-8, and MCP-1 expression in AVICs. Simvastatin down-regulated TLR4 levels and suppressed TLR4-induced phosphorylation of nuclear factor-kappa B. CONCLUSIONS: These data demonstrate the potential of a medical therapy (simvastatin) to impact the pathogenesis of aortic stenosis.

Severe ischemic cardiomyopathy with mechanical complications: Still a surgical disease.

BACKGROUND: Surgical treatment of ischemic cardiomyopathy (ICM) with mechanical complications has been limited in favor of suboptimal treatments because of the perception of poor outcome. METHODS AND RESULTS: From May 2009 till June 2014 115 patients with severe ICM (ejection fraction, EF, ≤25%) and mechanical complications were operated on. Median EF was 24% (19, 24), mean end-systolic volume index (ESVi) was 86±27ml/m2 and all patients had an MR grade of 2 or more. The right ventricle (RV) was hypokinetic in 33 patients. All of them underwent mitral valve surgery. Left ventricular (LV) surgical remodeling was performed in 60 patients (52.2%) and tricuspid surgery in 58 (50.4%). In-hospital mortality was 4.3% (5 patients). Six-year freedom from death any cause and from death any cause and NYHA class III/IV were, respectively, 70.5±4.9% and 66.4±4.8%. Cox regression analysis showed that risk factors were lower EF (cutpoint≤20%) and RV hypokinesia. Eighty-six patients had a follow up echocardiogram after a median of 31 (19, 51) months. EF increased by 60%, from 24 (19, 24) to 35 (27 ,46) (p=0.00), and ESVi decreased by 32%, from 87±29 to 59±27ml/m2 (p=0.00). SVi increased by 32%, from 23±7 to 32±12ml/m2. MR grade was ≥2 only in 6 patients (7%) and was not severe in any of them. CONCLUSIONS: Surgery for severe ICM with MR can be performed with low surgical risk and good midterm survival. These findings have to be taken into account while abandoning a clear surgical indication in favor of suboptimal alternative therapies.

Scar Homogenization Versus Limited-Substrate Ablation in Patients With Nonischemic Cardiomyopathy and Ventricular Tachycardia.

BACKGROUND: Scar homogenization improves long-term ventricular arrhythmia-free survival compared with standard limited-substrate ablation in patients with post-infarction ventricular tachycardia (VT). Whether such benefit extends to patients with nonischemic cardiomyopathy and scar-related VT is unclear. OBJECTIVES: The aim of this study was to assess the long-term efficacy of an endoepicardial scar homogenization approach compared with standard ablation in this population. METHODS: Consecutive patients with dilated nonischemic cardiomyopathy (n = 93), scar-related VTs, and evidence of low-voltage regions on the basis of pre-defined criteria on electroanatomic mapping (i.e., bipolar voltage <1.5 mV) underwent either standard VT ablation (group 1 [n = 57]) or endoepicardial ablation of all abnormal potentials within the electroanatomic scar (group 2 [n = 36]). Acute procedural success was defined as noninducibility of any VT at the end of the procedure; long-term success was defined as freedom from any ventricular arrhythmia at follow-up. RESULTS: Acute procedural success rates were 69.4% and 42.1% after scar homogenization and standard ablation, respectively (p = 0.01). During a mean follow-up period of 14 ± 2 months, single-procedure success rates were 63.9% after scar homogenization and 38.6% after standard ablation (p = 0.031). After multivariate analysis, scar homogenization and left ventricular ejection fraction were predictors of long-term success. During follow-up, the rehospitalization rate was significantly lower in the scar homogenization group (p = 0.035). CONCLUSIONS: In patients with dilated nonischemic cardiomyopathy, scar-related VT, and evidence of low-voltage regions on electroanatomic mapping, endoepicardial homogenization of the scar significantly increased freedom from any recurrent ventricular arrhythmia compared with a standard limited-substrate ablation. However, the success rate with this approach appeared to be lower than previously reported with ischemic cardiomyopathy, presumably because of the septal and midmyocardial distribution of the scar in some patients.

Catheter ablation of focal atrial tachycardia originating from a donor heart after bicaval orthotopic heart transplantation guided by a noncontact mapping system.

A 19-year-old man who underwent bicaval orthotopic heart transplantation for idiopathic dilated cardiomyopathy complained of palpitations 2 weeks after the heart transplantation. An ECG revealed paroxysmal atrial tachycardia (AT) with a cycle length of 260 ms and the P wave morphology of the AT was similar to that during sinus rhythm. Echocardiography showed normal contraction. No rejection, vasculopathy, or infection was observed. An electrophysiologic study and catheter ablation guided by a noncontact mapping system were performed due to drug refractory AT. The AT was induced spontaneously by isoproterenol infusion. The activation sequence of the AT exhibited a focal pattern, and the breakout site of the AT into the donor right atrium was just 12 mm below the breakout site of the donor sinoatrial node. Radiofrequency catheter ablation eliminated this AT and resulted in an improvement in the symptoms.

Persistent hypocalcemia associated with therapeutic plasma exchange performed to reduce HLA antibody levels in cardiac transplant recipients.

BACKGROUND: Patients who receive heart transplants may undergo therapeutic plasma exchange to reduce high levels of HLA antibodies which may increase the risk of allograft rejection. Plasma exchange may predispose to hypocalcemia because of chelation of calcium by sodium citrate, used as an anticoagulant both during the procedure and in thawed fresh frozen plasma often used for replacement. METHODS: We report three adults with dilated cardiomyopathy who underwent cardiac transplantation and serial plasma exchange for high levels of HLA antibodies. We followed these patients' pre-exchange serum calcium levels and the quantity of calcium supplementation they received. Further, we examined myocardial tissue sections post-transplantation for calcium deposition. RESULTS: Our patients' serum calcium levels were initially normal, but, despite aggressive calcium repletion, remained low (nadirs for pre-exchange ionized calcium in two patients 4.48 and 3.8mg/dL, respectively, reference range 4.6-5.4mg/dL). For patient 3, pre-exchange total calcium on day 2 was 7.9mg/dL (reference range 8.4-10.2mg/dL). Two patients had intermittent symptoms of hypocalcemia. Studies of cardiac tissue sections (available only from these two patients) were consistent with the presence of calcium deposition post transplantation. In comparison, six patients who underwent lung transplantation and plasma exchange for high levels of HLA antibodies did not manifest significant hypocalcemia. CONCLUSIONS: We emphasize the need for prompt and sufficient calcium replacement, monitored by serum ionized calcium levels, in the early post-cardiac transplantation period when plasma exchange is performed with thawed fresh frozen plasma replacement. The persistently low serum calcium levels we observed post heart transplantation were possibly contributed to by increased myocardial calcium influx.

[Usefulness of intracoronary therapy with progenitor cells in patients with dilated cardiomyopathy: Bridge or alternative to heart transplantation?]. / Utilidad de la terapia intracoronaria con células progenitoras en pacientes con miocardiopatía dilatada: ¿puente o alternativa al trasplante cardiaco?

INTRODUCTION AND OBJECTIVES: Some paediatric publications have recently raised the value of intracoronary therapy with autologous bone marrow-derived progenitor cells (APCs) in children with dilated cardiomyopathy (DCM) and heart failure. We describe the usefulness of this treatment in two infants with severe DCM and heart failure, who had been transferred to our hospital for cardiac transplant evaluation. PATIENTS AND METHODS: The first patient was a 3 months old male weighing 4 kg. The second was a 4 months old male weighing 5 kg. At the time of admission, both were in poor clinical condition (NYHA IV), with severe dilation and systolic dysfunction (ejection fraction [EF]<30%) of the left ventricle and marked elevation of NT-proBNP, requiring treatment with mechanical ventilation and inotropic iv infusion. After mobilization with G-CSF for 4 days, APCs were obtained from peripheral blood by leukocytapheresis, administering them by a slow intracoronary bolus injection using a stop-flow technique (6.15x106 CD34-positive cells/Kg in the first patient, and 10.55x106 CD34-positive cells/Kg in the second). RESULTS: Since the first week after the procedure, clinical status of patients improved and echocardiography showed a decrease in left ventricular dilation. A month later, there was a significant improvement in EF (> 40%) and NT-proBNP levels, subsequently maintained throughout the follow-up. However, four months later in the first patient, the left ventricle dilated again and its function slightly worsened, but without any significant impact in his clinical status. CONCLUSIONS: Intracoronary therapy with APCs can be an alternative in children, especially infants, with DCM and heart failure. It can reduce the waiting list mortality, improve clinical status and provide more time on the waiting list to receive a suitable organ, or even to make transplantation unnecessary.

Orthotopic heart transplantation: two parts of the heart with two different arrhythmias.

An unusual case of two different types of atrial arrhythmia after orthotopic heart transplantation is reported: a macro-reentrant atrial tachycardia in the recipient atrium, and a common-type, counterclockwise, isthmus-dependent atrial flutter in the donor atrium. The clinical symptoms were caused by atrial flutter arising from the donor atrium. Radiofrequency catheter ablation of the electrically active, donor-derived portion of the cavotricuspid isthmus was performed successfully.

Vertebral artery dissection after iatrogenic cervical subcutaneous emphysema.

We report a case of spontaneous vertebral artery dissection (VAD) in a patient who developed extensive subcutaneous emphysema following the removal of a chest tube after a cardiac transplant. The pathophysiology and management of this uncommon complication are reviewed. Although vertebral and carotid artery dissections are unusual events occurring in 2.5 to 3 per 100,000 people, they are increasingly acknowledged to be important causes of stroke in the young and middle-aged adult population accounting for up to 25% of such cases. VADs are associated with a variety of minor traumatic mechanisms including painting a ceiling, yoga, chiropractic manipulation of the spine, and driving. These events cause injury to the vessel wall either by shearing forces secondary to rotational injuries or direct trauma to the vessel wall on bony prominences, especially the transverse processes of the cervical vertebrae. We present a case of a patient with documented previously normal vertebral arterial anatomy who developed a VAD after mediastinal tube removal resulted in subcutaneous emphysema tracking through fascial planes into his neck.

Bloqueio simpático esquerdo por videotoracoscopia no tratamento da cardiomiopatia dilatada / Endoscopic left sympathetic blockade in the treatment for dilated cardiomyopathy / Bloqueo simpático izquierdo por videotoracoscopia en el tratamiento de la cardiomiopatía dilatada

FUNDAMENTO: O nível da atividade nervosa simpática é um dos mais importantes determinantes prognósticos em pacientes com insuficiência cardíaca. OBJETIVO: O propósito dessa investigação foi realizar um estudo de viabilidade do emprego do bloqueio simpático esquerdo por toracoscopia em pacientes com insuficiência cardíaca (IC) para avaliar a segurança e os efeitos imediatos. MÉTODOS: Quinze pacientes com cardiomiopatia dilatada e fração de ejeção do ventrículo esquerdo (FEVE) < 40 por cento, classe funcional II ou III (NYHA) e frequência cardíaca > 65 bpm, a despeito do uso adequado de beta-bloqueadores ou intolerantes a eles, forma selecionados. Dez pacientes foram submetidos à clipagem do espaço inter-espinhal em nível de T3-T4 e da porção inferior dos gânglios estrelados esquerdos através de videotoracocopia, enquanto outros cinco pacientes foram randomizados para um grupo controle. RESULTADOS: Nenhum dos pacientes operados apresentou qualquer evento cardiovascular adverso relacionado ao procedimento cirúrgico no período perioperatório. Dois pacientes do grupo cirúrgico morreram devido a tromboembolismo pulmonar ou infarto do miocárdio nos 6 meses de seguimento inicial, enquanto três pacientes do grupo controle apresentaram progressão da IC e morreram ou desenvolveram choque cardiogênico no mesmo período. Nos pacientes tratados, houve melhora na qualidade de vida, nível de atividade física e FEVE (de 25 ± 9 por cento para 32 ± 8 por cento, p=0,024) aos 6 meses de seguimento, enquanto esses parâmetros não se alteraram nos pacientes do grupo controle. CONCLUSÃO: O bloqueio simpático esquerdo via toracoscopia é factível e parece ser seguro em pacientes com IC grave. Esse estudo inicial sugere que esse procedimento pode ser uma abordagem alternativa eficaz para o bloqueio simpático no tratamento de cardiomiopatias dilatadas.

BACKGROUND: The level of sympathetic nervous activity is a major determinant of prognosis in patients with heart failure. OBJECTIVE: The purpose of this investigation was to perform a proof-of-principle trial of therapeutic endoscopic left thoracic sympathetic blockade in heart failure patients to assess safety and immediate effects. METHODS: Fifteen patients with dilated cardiomyopathy and left ventricular ejection fraction (LVEF) < 40 percent, New York Heart Association functional class II or III, and heart rate > 65 bpm, despite either adequate betablocker use or intolerant to it, were enrolled. Ten patients underwent left infra-stellate ganglion plus T3-T4 interspinal space clipping through videothoracoscopy, while the other five patients were randomized to a control group. RESULTS: None of the treated patients had any procedure-related adverse cardiovascular events at the perioperative period. Two patients from the surgical group died due to pulmonary thromboembolism or myocardial infarction within 6 months of the initial follow-up, while three patients from the control group had heart failure progression and died or developed cardiogenic shock during the same period. Treated patients presented improvement in quality of life, level of physical activity and LVEF (from 25 ± 9 percent to 32 ± 8 percent, p=0.024) at 6 months of follow-up, whereas these parameters did not change in control patients. CONCLUSION: Endoscopic left thoracic sympathetic blockade is feasible and appears to be safe in severe heart failure patients. This initial study suggests that this procedure might be an effective alternative approach to sympathetic blockade in the treatment of dilated cardiomyopathies.

FUNDAMENTO: El nivel de la actividad nerviosa simpática es uno de los más importantes determinantes pronósticos en pacientes con insuficiencia cardíaca. OBJETIVO: El propósito de esta investigación fue realizar un estudio de viabilidad del empleo del bloqueo simpático izquierdo por toracoscopia en pacientes con insuficiencia cardíaca (IC) para evaluar la seguridad y los efectos inmediatos. MÉTODOS: Quince pacientes con cardiomiopatía dilatada y fracción de eyección del ventrículo izquierdo (FEVI) < 40 por ciento, clase funcional II o III (NYHA) y frecuencia cardíaca > 65 lpm, a despecho del uso adecuado de betabloqueantes o intolerantes a ellos, fueron seleccionados. Diez pacientes fueron sometidos a clipaje del espacio interespinal a nivel de T3-T4 y de la porción inferior de los ganglios estrellados izquierdos a través de videotoracocopia, mientras que otros cinco pacientes fueron randomizados para un grupo control. RESULTADOS: Ninguno de los pacientes operados presentó ningún evento cardiovascular adverso relacionado al procedimiento quirúrgico en el período perioperatorio. Dos pacientes del grupo quirúrgico murieron debido a tromboembolismo pulmonar o infarto de miocardio en los 6 meses de seguimiento inicial, mientras tres pacientes del grupo control presentaron progresión de la IC y murieron o desarrollaron shock cardiogénico en el mismo período. En los pacientes tratados, hubo mejora en la calidad de vida, nivel de actividad física y FEVI (de 25±9 por ciento a 32±8 por ciento, p=0,024) a los 6 meses de seguimiento, mientras que esos parámetros no se alteraron en los pacientes del grupo control. CONCLUSIÓN: El bloqueo simpático izquierdo vía toracoscopia es factible y parece ser seguro en pacientes con IC grave. Este estudio inicial sugiere que este procedimiento puede ser un abordaje alternativo eficaz para el bloqueo simpático en el tratamiento de cardiomiopatías dilatadas.

Endoscopic left sympathetic blockade in the treatment for dilated cardiomyopathy.

BACKGROUND: The level of sympathetic nervous activity is a major determinant of prognosis in patients with heart failure. OBJECTIVE: The purpose of this investigation was to perform a proof-of-principle trial of therapeutic endoscopic left thoracic sympathetic blockade in heart failure patients to assess safety and immediate effects. METHODS: Fifteen patients with dilated cardiomyopathy and left ventricular ejection fraction (LVEF) < 40%, New York Heart Association functional class II or III, and heart rate > 65 bpm, despite either adequate betablocker use or intolerant to it, were enrolled. Ten patients underwent left infra-stellate ganglion plus T3-T4 interspinal space clipping through videothoracoscopy, while the other five patients were randomized to a control group. RESULTS: None of the treated patients had any procedure-related adverse cardiovascular events at the perioperative period. Two patients from the surgical group died due to pulmonary thromboembolism or myocardial infarction within 6 months of the initial follow-up, while three patients from the control group had heart failure progression and died or developed cardiogenic shock during the same period. Treated patients presented improvement in quality of life, level of physical activity and LVEF (from 25 ± 9% to 32 ± 8%, p=0.024) at 6 months of follow-up, whereas these parameters did not change in control patients. CONCLUSION: Endoscopic left thoracic sympathetic blockade is feasible and appears to be safe in severe heart failure patients. This initial study suggests that this procedure might be an effective alternative approach to sympathetic blockade in the treatment of dilated cardiomyopathies.

Focal atrial tachycardia originating from the donor superior vena cava after bicaval orthotopic heart transplantation.

An 11-year-old boy, who underwent bicaval orthotopic heart transplantation for idiopathic dilated cardiomyopathy, had a focal atrial tachycardia originating from the donor superior vena cava. The pathogenesis of this tachycardia may be related to transplant rejection or transplant vasculopathy. Radiofrequency catheter ablation can eliminate this unique tachycardia and result in hemodynamic improvement.

[Successful use of recombinant factor VIIa in the control of a massive bleeding in two patients with biventricular assist device (Thoratec)]. / Utilisation bénéfique de facteur VIIa recombinant chez deux patients porteurs d'une assistance biventriculaire (Thoratec).

Massive bleeding is a dreaded complication of biventricular mechanical assistance implantation. Its origin is multifactorial. Blood products transfusion associated with correction of coagulopathy are sometimes insufficient. We report two cases of massive bleeding after a Thoratec biventricular assistance implantation. After surgical haemostasis failure and despite the correction of coagulation disorders, a major bleeding persisted, so these patients received a single injection of 90 microg/kg of rFVIIa. This allowed in both cases a significant reduction of the bleeding and the restoration of normal haemodynamic conditions. This treatment was not complicated by any thrombotic accident.

Cardiomyopathy induced by adenosine-insensitive atrial tachycardia.

Tachycardia-induced cardiomyopathy may be provoked by several arrhythmias; it may reverse following stable restoration of sinus rhythm. We report the case of a 33-year-old man who was diagnosed to have a dilated cardiomyopathy. Over a few months, the cardiomyopathy reversed. Subsequently, atrial tachycardia, associated with a recurrent impairment of left ventricular function, occurred. Adenosine infusion during atrial tachycardia caused transient atrioventricular block without the interruption of arrhythmia, which is consistent with a micro-reentrant mechanism. Electroanatomic mapping during tachycardia showed a focus arising from the left superior pulmonary vein ostium. After successful catheter ablation of the focus, left ventricular function fully recovered.

Programmed cell death in idiopathic dilated cardiomyopathy is mediated by suppression of the apoptosis inhibitor Apollon.

BACKGROUND: Idiopathic dilated cardiomyopathy (DCM) is characterized by ventricular wall remodeling and an increased frequency of cardiac cell apoptosis. Apollon is a 528kD cell membrane-anchored protein that inhibits apoptosis by ubiquitinylation facilitating the degradation of Smac/Diablo and caspase-9. The present study tested the hypothesis that the Apollon/Smac system may mediate programmed cell death in DCM. METHODS: Apollon and caspase-9 protein expression was assessed in left ventricular biopsies of explanted failing hearts using Western blotting in 36 DCM patients undergoing cardiac transplantation and in 10 controls. Human cardiac cells were transfected with a plasmid containing the human Apollon complementary DNA or control vector and were subsequently stressed by hypoxia. Apollon, Smac/Diablo, and caspase-9 expression were then examined in cell lysates by real-time polymerase chain reaction and a transferase-mediated dUTP nick-end labeling assay was used to determine the apoptotic index. RESULTS: In DCM myocardial tissue, Apollon messenger (m)RNA and protein expression was down-regulated compared with control hearts (p < 0.001 and p < 0.005, respectively) concomitant with an increase in activated caspase-9 protein levels (p < 0.001). Cell stress resulted in increased apoptosis in cardiac cells in vitro and down-regulation of Apollon mRNA expression compared with control cells (p < 0.001). Transfection increased Apollon mRNA expression in cell lysates (p < 0.001) and completely prevented hypoxia-induced apoptosis associated with reduced expression of Smac/Diablo and activated caspase-9. CONCLUSIONS: These results suggest that Apollon down-regulation plays a role in programmed cell death associated with DCM. Up-regulation of Apollon might therefore represent a novel therapeutic strategy in the treatment of DCM.

Treatment of recurrent chest pain in a heart transplant recipient using spinal cord stimulation.

A patient presented with chest pain refractory to conventional medical therapy eight years after heart and renal transplantation. High-dose opioids provided limited relief and repeated hospitalisation was required. Angiography demonstrated severe cardiac allograft vasculopathy, unsuitable for percutaneous or surgical intervention. Reports of sympathetic re-innervation of the transplanted heart encouraged us to undertake a trial of spinal cord stimulation. This was successful so we proceeded to permanent implantation. The patient was weaned from opioids and after six months had needed no further hospital admissions. We recommend consideration of spinal cord stimulation in patients with features of angina pectoris following heart transplantation.

Catheter ablation of premature ventricular contraction-induced cardiomyopathy.

BACKGROUND: A 44-year-old female presented with a long history of chest pain, palpitations and increasing dyspnea. Electrocardiography and 24 h Holter monitoring revealed multiple premature ventricular complexes (PVCs), and echocardiography demonstrated significant left ventricular dilatation and systolic impairment. After further investigation it was concluded that this cardiomyopathy was secondary to the observed multiple PVCs and that these represented a potential target for treatment. INVESTIGATIONS: Electrocardiography, echocardiography, cardiac MRI, 24 h Holter monitoring, coronary angiography, tilt testing and invasive electrophysiological testing using a multielectrode array catheter. DIAGNOSIS: PVC-induced dilated cardiomyopathy. MANAGEMENT: Electrophysiological mapping and cryoablation of the focus of the ventricular ectopy.

Effect of defibrillation testing on management during implantable cardioverter-defibrillator implantation.

BACKGROUND: Verification of defibrillation efficacy by defibrillation threshold (DFT) testing during implantable cardioverter-defibrillator implantation is the current standard. Generally, defibrillation of ventricular fibrillation at 10 J below the maximum output of a device is felt to establish an adequate safety margin. Nonetheless, DFT testing adds to cost and carries some potential for morbidity, whereas its impact on outcomes in the modern era of defibrillator technology is unclear. We aimed to determine the frequency that DFT testing resulted in a change at device implant and to identify clinical and echocardiographic predictors of the need for DFT testing. METHODS: We reviewed all implantable cardioverter-defibrillators that were implanted at the London Health Sciences Centre (Ontario, Canada) from June 1999 to August 2003 and used multivariate analysis to determine variables associated with DFT test failures and elevated DFT values. When a defibrillation failure was not observed, a lowest energy to defibrillate (LED) was recorded. RESULTS: Among 168 implants, DFT testing was successful with a minimum 10-J safety margin in 152 (90%), whereas the remaining 16 required changes at device implant. In a multivariate analysis, use of amiodarone was independently associated with DFT failure (odds ratio, 4.6; 95% confidence interval, 1.2-17.0). Significantly higher mean DFT/LED values were observed among patients on amiodarone (1.36 J; P = .0041). Those with nonischemic cardiomyopathy had a higher mean DFT/LED compared with those with ischemic cardiomyopathy (1.44 J; P = .028). CONCLUSIONS: Use of amiodarone is associated with a 4-fold increase in risk of DFT failure and subsequent need for changes at implant to achieve a safe threshold. Defibrillation threshold testing appears to be most useful for patients taking amiodarone.