Lise-Andrée Mercier

Angiotensin Receptor Blockade and Exercise Capacity in Adults With Systemic Right Ventricles A Multicenter, Randomized, Placebo-Controlled Clinical Trial

Background— Pharmacological blockade of the renin-angiotensin system improves exercise tolerance in patients with left ventricular dysfunction, yet its impact on patients with systemic right ventricles (RVs) remains unknown. Methods and Results— A multicenter, randomized, double-blind, placebo-controlled, crossover clinical trial was performed to assess the effects of losartan on exercise capacity and neurohormonal levels in patients with systemic RVs. Of 29 patients studied (age, 30.3±10.9 years), 21 had transposition of the great arteries with a Mustard baffle, and 8 had congenitally corrected transposition of the great arteries. Baseline values were as follows: &OV0312;o2max, 29.8±5.6 mL · kg−1 · min−1 (73.5±12.9% predicted value); RV ejection fraction, 41.6±9.3%; N-terminal pro brain natriuretic peptide (NT-proBNP), 257.7±243.4 pg/mL (normal <125 pg/mL); and angiotensin II, 5.7±4.9 pg/mL (normal <5.0 pg/mL). Comparing losartan to placebo showed no differences in &OV0312;o2max (29.9±5.4 versus 29.4±6.2 mL · kg−1 · min−1; P=0.43), exercise duration (632.3±123.0 versus 629.9±140.7 seconds; P=0.76), and NT-proBNP levels (201.2±267.8 versus 229.7±291.5 pg/mL; P=0.10), despite a trend toward increased angiotensin II levels (15.2±13.8 versus 8.8±12.5 pg/mL; P=0.08). Conclusions— In adults with systemic RVs, losartan did not improve exercise capacity or reduce NT-proBNP levels. Minimal baseline activation of the renin-angiotensin system may explain this lack of benefit and imply an alternative pathophysiological mechanism for the progressive ventricular dysfunction and impaired exercise capacity observed in such patients.

Transvenous Pacing Leads and Systemic Thromboemboli in Patients With Intracardiac Shunts. A Multicenter Study

Background— The risk of systemic thromboemboli associated with transvenous leads in the presence of an intracardiac shunt is currently unknown. Methods and Results— To define this risk, we conducted a multicenter, retrospective cohort study of 202 patients with intracardiac shunts: Sixty-four had transvenous leads (group 1), 56 had epicardial leads (group 2), and 82 had right-to-left shunts but no pacemaker or implantable cardioverter defibrillator leads (group 3). Patient-years were accrued until the occurrence of systemic thromboemboli or study termination. Censoring occurred in the event of complete shunt closure, death, or loss to follow-up. Mean ages for groups 1, 2, and 3 were 33.9±18.0, 22.2±12.6, and 22.9±15.0 years, respectively. Respective oxygen saturations were 91.2±9.1%, 88.1±8.1%, and 79.7±6.7%. During respective median follow-ups of 7.3, 9.3, and 17.0 years, 24 patients had at least 1 systemic thromboembolus: 10 (15.6%), 5 (8.9%), and 9 (11.0%) in groups 1, 2, and 3, respectively. Univariate risk factors were older age (hazard ratio [HR], 1.05; P=0.0001), ongoing phlebotomy (HR, 3.1; P=0.0415), and an transvenous lead (HR, 2.4; P=0.0421). In multivariate, stepwise regression analyses, transvenous leads remained an independent predictor of systemic thromboemboli (HR, 2.6; P=0.0265). In patients with transvenous leads, independent risk factors were older age (HR, 1.05; P=0.0080), atrial fibrillation or flutter (HR, 6.7; P=0.0214), and ongoing phlebotomy (HR, 14.4; P=0.0349). Having had aspirin or warfarin prescribed was not protective. Epicardial leads were, however, associated with higher atrial (P=0.0407) and ventricular (P=0.0270) thresholds and shorter generator longevity (HR, 1.9; P=0.0176). Conclusions— Transvenous leads incur a >2-fold increased risk of systemic thromboemboli in patients with intracardiac shunts.

Sudden Death and Defibrillators in Transposition of the Great Arteries With Intra-atrial Baffles A Multicenter Study

Background—Transposition of the great arteries with intra-atrial baffle repair is among the congenital heart defects at highest risk of sudden death. Little is known about mechanisms of sudden death and the role of implantable cardioverter defibrillators. Methods and Results—We conducted a multicenter cohort study in patients with transposition of the great arteries to determine actuarial rates of implantable cardioverter defibrillator shocks, identify risk factors, assess underlying arrhythmias, and characterize complications. Overall, 37 patients (age, 28.0±7.6 years; 89.2% male) were enrolled from 7 sites. Implantable cardioverter defibrillators were implanted for primary prevention in 23 (62.1%) patients and secondary prevention in 14 patients (37.8%). Annual rates of appropriate shocks were 0.5% and 6.0% in primary and secondary prevention, respectively (P=0.0366). Independent predictors were a secondary prevention indication (hazard ratio, 18.0; P=0.0341) and lack of &bgr;-blockers (hazard ratio, 16.7; P=0.0301). In patients with appropriate shocks, intracardiac electrograms documented supraventricular tachycardia preceding or coexisting with ventricular tachycardia in 50%. No patient with inducible ventricular tachycardia received an appropriate shock in comparison with 37.5% of noninducible patients (P=0.0429). Inappropriate shocks occurred in 6.6% per year, more so in patients of lesser weight (hazard ratio, 0.91 per kg; P=0.0168). Additionally, 14 patients (37.8%) experienced complications: 5 (13.5%) acute, 1 (2.7%) late generator related, and 12 (32.4%) late lead related. Conclusion—In patients with transposition of the great arteries, high rates of appropriate shocks are noted in secondary but not primary prevention. Supraventricular arrhythmias may be implicated in the etiology of ventricular tachyarrhythmias; &bgr;-blockers seem protective, and inducible ventricular tachycardia does not seem to predict future events. Inappropriate shocks and late lead-related complications are common.

Improvement in Exercise Capacity in Asymptomatic and Mildly Symptomatic Adults After Atrial Septal Defect Percutaneous Closure

Background—Controversy exists as to whether secundum atrial septal defects (ASDs) in asymptomatic or mildly symptomatic New York Heart Association (NYHA) class I or II adult patients should be closed. Methods and Results—Thirty-seven patients (24 females; mean age 49.4 years, range 19 to 76) with a mean pulmonary to systemic flow ratio (Qp:Qs) of 2.1 (1.2 to 3.4) had a maximal oxygen uptake (Vo2max) determination and echocardiographic measurement of right ventricular dimensions before and 6 months after elective percutaneous closure of ASD. At baseline, mean Vo2max was 23.5±6.4 mL/kg per minute and was higher in the 15 NYHA I patients than in the 22 NYHA II patients (27±6.9 versus 20.8±4.6 mL/kg per minute;P =0.0015). Vo2max increased significantly at 6 months (23.5±6.4 to 26.9±6.9 mL/kg per minute;P <0.0001). Improvement was as marked in NYHA I (+22%;P <0.0001) as in NYHA II patients (+12%;P <0.0001), in patients with Qp:Qs 1.2 to 2.0 (+16%;P <0.0001) as in those with Qp:Qs >2 (+12%;P <0.0001), and in patients ≥40 years of age (+14%;P <0.0001) as in those <40 years of age (+16%;P <0.0001). Compared with 15 of 37 patients before closure, 35 of 37 patients were in NYHA I at 6 months. Right ventricular dimensions decreased significantly (P <0.0001). Conclusions—Adult ASD patients significantly increase their functional capacity after percutaneous defect closure. This is observed even in patients classified as asymptomatic, in those with lesser shunts, and in older patients. These findings suggest that ASD closure in an adult population should be considered even in the absence of symptoms.

Simultaneous Determination of Aortic Valve Area by the Gorlin Formula and by Transesophageal Echocardiography Under Different Transvalvular Flow Conditions: Evidence That Anatomic Aortic Valve Area Does Not Change With Variations in Flow in Aortic Stenosis☆

OBJECTIVES The purpose of this study was to determine the impact of changes in flow on aortic valve area (AVA) as measured by the Gorlin formula and transesophageal echocardiographic (TEE) planimetry. BACKGROUND The meaning of flow-related changes in AVA calculations using the Gorlin formula in patients with aortic stenosis remains controversial. It has been suggested that flow dependence of the calculated area could be due to a true widening of the orifice as flow increases or to a disproportionate flow dependence of the formula itself. Alternatively, anatomic AVA can be measured by direct planimetry of the valve orifice with TEE. METHODS Simultaneous measurement of the planimetered and Gorlin valve area was performed intraoperatively under different hemodynamic conditions in 11 patients. Left ventricular and ascending aortic pressures were measured simultaneously after transventricular and aortic punctures. Changes in flow were induced by dobutamine infusion. Using multiplane TEE, AVA was planimetered at the level of the leaflet tips in the short-axis view. RESULTS Overall, cardiac output, stroke volume and transvalvular volume flow rate ranged from 2.5 to 7.3 liters/min, from 43 to 86 ml and from 102 to 306 ml/min, respectively. During dobutamine infusion, cardiac-output increased by 42% and mean aortic valve gradient by 54%. When minimal flow was compared with maximal flow, the Gorlin area varied from (mean +/- SD) 0.44 +/- 0.12 to 0.60 +/- 0.14 cm2 (p < 0.005). The mean change in Gorlin area under different flow rates was 36 +/- 32%. Despite these changes, there was no significant change in the planimetered area when minimal flow was compared with maximal flow. The mean difference in planimetered area under different flow rates was 0.002 +/- 0.01 cm2 (p = 0.86). CONCLUSIONS By simultaneous determination of Gorlin formula and TEE planimetry valve areas, we showed that acute changes in transvalvular volume flow substantially altered valve area calculated by the Gorlin formula but did not result in significant alterations of the anatomic valve area in aortic stenosis. These results suggest that the flow-related variation in the Gorlin AVA is due to a disproportionate flow dependence of the formula itself and not a true change in valve area.

Risk stratification in surgically repaired tetralogy of Fallot.

Tetralogy of Fallot is the most common form of congenital heart disease in implantable cardioverter–defibrillator (ICD) recipients. Indeed, sudden death of presumed arrhythmic etiology is the most frequent mode of demise in patients with surgically repaired tetralogy of Fallot, often in early-to-mid adulthood. Nevertheless, the overall annual incidence of sudden death is actually low. Therein lies the major challenge of risk stratification. This review highlights some of the complexities involved in risk stratifying patients with tetralogy of Fallot, underscoring the importance of avoiding oversimplification by means of a rigid algorithm that dictates therapy. To complement sound clinical judgment, a quantitative probabilistic approach is presented, which considers the body of literature from primary prevention ICD trials, risk factors identified by observational studies, the value of programmed ventricular stimulation and insights gleaned from studying ICD recipients with tetralogy of Fallot.

Arrhythmias in adult congenital heart disease

Recent advances in pediatric cardiology and cardiac surgery have allowed a rapidly expanding population of patients with congenital heart disease to thrive well into their adult years. Often after prolonged uneventful clinical courses as children and adolescents, arrhythmias may surface later in life. These arrhythmias are a major source of morbidity. In addition, sudden death is the leading cause of mortality in adult patients with congenital heart disease. This review highlights the various types of brady- and tachyarrhythmias encountered in the more common forms of adult congenital heart disease and explores prognostic implications and therapeutic options.

Implantable cardioverter defibrillators in adults with congenital heart disease: a single center experience.

Sudden death is the most frequent cause of late mortality in adults with congenital heart disease. This study reviews the experience of an Adult Congenital Heart Center with the use of implantable cardioverter defibrillators (ICDs). The charts of adults with congenital heart disease who had an ICD implantation were reviewed for diagnosis, residual lesions, reoperations, reason for implantation, complications, and recurrence of arrhythmias. Since 1995, 13 patients (mean age 43 years) had an ICD implantation for aborted sudden death (4), and spontaneous (6), or induced (3) ventricular tachycardia. Diagnosis were repaired (6) or palliated (1) tetralogy of Fallot, operated pulmonary stenosis (2), palliated complex pulmonary atresia (1), congenitally corrected transposition (1), operated ventricular (1), and atrial (1) septal defects. Significant residual lesions included severe pulmonary regurgitation (2), systemic ventricular dysfunction (2), and severe pulmonary hypertension (1). Five patients had a QRS > 180 ms, four had a QRS < 180 ms, four had a paced rhythm. Overall, four (31%) patients had no ventricular dysfunction, no residual lesion, and QRS < 180 ms. During a mean follow‐up of 29 months, seven patients had recurrent ventricular tachycardia, three with normal ventricular function, no residual lesion, and QRS < 180 ms. ICD implantation is an important adjunct in the management of adults with congenital heart disease. As malignant arrhythmias occur even in patients with no residual lesion, no QRS prolongation and no ventricular dysfunction, the recognition of those who would benefit from an ICD remains a clinical challenge. (PACE 2004; 27:47–51)

Pulmonary Arterial Hypertension in Patients With Transcatheter Closure of Secundum Atrial Septal Defects A Longitudinal Study

Background—Pulmonary arterial hypertension (PAH) may develop in patients with atrial septal defects (ASD); however, little is known about associated risk factors and its evolution after transcatheter ASD closure. Methods and Results—We conducted a cohort study on 215 adults with attempted transcatheter ASD closure from 1999 to 2006. Patients were classified according to baseline systolic pulmonary artery pressures as having no (I, <40 mm; Hg), mild (II, 40 to 49 mm; Hg), moderate (III, 50 to 59 mm; Hg), or severe (IV, ≥60 mm; Hg) PAH. Independent predictors of moderate or severe PAH were older age (odds ratio [OR], 1.10 per year; P<0.0001), larger ASD (OR, 1.13 per millimeter; P=0.0052), female sex (OR, 3.9; P=0.0313), and at least moderate tricuspid regurgitation (OR, 3.6; P=0.0043). At 15 (interquartile range, 8 to 43) months post–ASD closure, patients with higher baseline pressures were more likely to experience a ≥5-mm; Hg decrease (33.7%, 73.9%, 79.2%, and 100.0% in groups I to IV, P<0.0001), with a larger magnitude of reduction (0, 8, 17, and 22 mm; Hg; P<0.0001). However, normalization of pressures (<40 mm; Hg) occurred less frequently in patients with more advanced PAH (90.2%, 71.7%, 66.7%, and 23.5%, P<0.0001). Among patients with moderate or severe PAH, independent predictors of normalization were lower baseline pressures (OR, 0.91 per mm; Hg; P=0.0418) and no more than mild tricuspid regurgitation (OR, 0.14; P=0.0420). Conclusion—In adults with ASDs, severity of PAH is modulated by age, sex, defect size, and degree of tricuspid regurgitation. Patients with moderate or severe PAH may benefit from substantial reductions in pulmonary artery pressures after transcatheter ASD closure, although the PAH values remain elevated in a sizeable proportion.

Fontan Circulation: Success or Failure?

Fontan surgery represents a milestone in the evolution of congenital heart disease management. It achieved the seemingly improbable (ie, restoration of a noncyanotic state by entirely bypassing the subpulmonary ventricle). In so doing, it has allowed a generation of children who may have otherwise succumbed to their severe congenital heart defect to survive to adulthood. Perfect univentricular physiology is, however, an elusive goal. The Fontan circulation inherently represents a hemodynamic compromise that results in a catalog of potential multiorgan complications. In this review, we explore current knowledge regarding pathophysiology of the failing Fontan, its varied clinical manifestations, and potential therapeutic options. Failure of the Fontan circulation is broadly divided into 3 overlapping categories: ventricular dysfunction, systemic complications of Fontan physiology, and chronic Fontan failure. As long as the Fontan operation continues to serve as the paradigm of care for patients with univentricular hearts, efforts must be directed toward supporting this dynamic circulation that progressively declines in efficiency with age. Continued research in therapies is needed for univentricular dysfunction and systemic complications of Fontan palliation, including potential uses of mechanical support as a bridge to transplantation or as a neosubpulmonary ventricle. Fontan patients remain a major challenge to the medical and surgical community as a whole. Multicentre and multidisciplinary efforts to improve the density and depth of experiences might lead to a better appreciation for, and management of, Fontan failure and its ramifications.