Stephane Lafitte

Detrimental Ventricular Remodeling in Patients With Congenital Complete Heart Block and Chronic Right Ventricular Apical Pacing

Background—Although dual-chamber pacing improves cardiac function in patients with complete congenital atrioventricular block (CCAVB) by restoring physiological heart rate and atrioventricular synchronization, the long-term detrimental effect of asynchronous electromechanical activation induced by apical right ventricular pacing (RVP) has not been well clarified. Methods and Results—Twenty-three CCAVB adults (24±3 years) with a DDD transvenous pacemaker underwent conventional echocardiography before implantation and, after at least 5 years of RVP, an exercise test and echocardiography coupled with tissue Doppler imaging and tissue tracking. They were compared with 30 matched healthy control subjects. After 10±3 years of RVP, CCAVB adults had significantly higher values versus controls in terms of intra–left ventricular (LV) asynchrony (respectively, 59±18 versus 19±9 ms, P<0.001), extent of LV myocardium displaying delayed longitudinal contraction (39±15% versus 10±7%, P<0.01), and septal-to-posterior wall-motion delay (84±26 versus 18±9 ms, P<0.01). The ratio of late-activated posterior to early-activated septal wall thickness was higher after long-term RVP than before (1.3±0.2 vs 1±0.1, P=0.05) and was higher than in controls (1±0.1, P<0.05). The percentage of patients with increased LV end-diastolic diameter was higher after long-term RVP than before implantation and was higher than in controls (57% versus 13%, P<0.05, and 57% versus 0%, P<0.01, respectively). CCAVB patients with long-term RVP had a lower cardiac output than controls (3.8±0.6 versus 4.9±0.8 L/min, P<0.05) and lower exercise performance (123±24 versus 185±39 W, P<0.001). Conclusions—Prolonged ventricular dyssynchrony induced by long-term endovenous RVP is associated with deleterious LV remodeling, LV dilatation, LV asymmetrical hypertrophy, and low exercise capacity. These new data highlight the importance of the ventricular activation sequence in all patients with chronic ventricular pacing.

Optimizing Hemodynamics in Heart Failure Patients by Systematic Screening of Left Ventricular Pacing Sites : The Lateral Left Ventricular Wall and the Coronary Sinus Are Rarely the Best Sites

OBJECTIVES We sought to evaluate the impact of the left ventricular (LV) pacing site on hemodynamic response to cardiac resynchronization therapy (CRT). BACKGROUND CRT reduces morbidity and mortality in heart failure patients. However, 20% to 40% of eligible patients may not fully benefit from CRT device implantation. We hypothesized that selecting the optimal LV pacing site could be critical in this issue. METHODS Thirty-five patients with nonischemic dilated cardiomyopathy referred for CRT device implantation were studied. Intraventricular dyssynchrony and latest activated LV wall were defined by tissue Doppler imaging analysis before the study. Eleven predetermined LV pacing sites were systematically assessed in random order: basal and mid-cavity (septal, anterior, lateral, inferior), apex, coronary sinus (CS), and the endocardial site facing the CS pacing site. For each patient, +dP/dT(max), -dP/dT(min), pulse pressure, and end-systolic pressure during baseline (AAI) and DDD LV pacing were compared. Two atrioventricular delays were tested. RESULTS Major interindividual and intraindividual variations of hemodynamic response depending on the LV pacing site were observed. Compared with baseline, LV DDD pacing at the best LV position significantly improved +dP/dT(max) (+31 +/- 26%, p < 0.001) and was superior to pacing the CS (+15 +/- 23%, p < 0.001), the lateral LV wall (+18 +/- 22%, p < 0.001), or the latest activated LV wall (+11 +/- 17%, p < 0.001). CONCLUSIONS The pacing site is a primary determinant of the hemodynamic response to LV pacing in patients with nonischemic dilated cardiomyopathy. Pacing at the best LV site is associated acutely with fewer nonresponders and twice the improvement in +dP/dT(max) observed with CS pacing.

Reverse Remodeling of the Left Cardiac Chambers After Catheter Ablation After 1 Year in a Series of Patients With Isolated Atrial Fibrillation

Background— Isolated atrial fibrillation (AF) is associated with mild enlargement of the left atrium (LA) and left ventricular (LV) diastolic dysfunction. The impact of ablation of isolated AF on left chamber size and function is unclear, and whether diastolic dysfunction is the cause or the consequence of AF remains unknown. The objective of this prospective study was to evaluate the impact of sinus rhythm restoration by catheter ablation on LV diastolic dysfunction, LA morphology, and mechanical function. Methods and Results— Forty-eight patients with isolated AF were studied by serial echocardiographic studies at baseline and at 1-, 3-, 6-, 9-, and 12-month intervals after radiofrequency ablation. LA dimensions and mechanical function and LV systolic and diastolic functions were evaluated at each time interval. Diastolic function was assessed with conventional Doppler parameters and new indexes such as tissue Doppler imaging, mitral flow propagation velocity, and combined criteria. LV diastolic dysfunction was present in paroxysmal and chronic AF patients with a reduction of tissue Doppler imaging lateral early diastolic peak velocity in 37% (P<0.001) and 48% (P<0.01), respectively, compared with healthy control subjects. At the end of the follow-up, LA area decreased significantly by 18% (P<0.001) in paroxysmal and 23% (P<0.05) in chronic AF patients. Diastolic function improved significantly with an increase in lateral early diastolic peak velocity of 29% (P<0.001) in paroxysmal AF and 46% (P<0.05) in chronic AF patients. A significant increase in LV ejection fraction was also noted for both groups: 7.7% and 18.8%, respectively. Conclusions— This study demonstrates reverse morphological remodeling of the LA and improvement of LV diastolic and systolic functions after restoration of sinus rhythm by ablation for isolated AF. Because patients with isolated AF have none of the traditional causes of LV diastolic dysfunction, our findings suggest that AF may be partly the cause rather than the consequence of diastolic dysfunction.

Experimental Validation of Circumferential, Longitudinal, and Radial 2-Dimensional Strain During Dobutamine Stress Echocardiography in Ischemic Conditions

OBJECTIVES The aim of this study was to assess and validate 2-dimensional (2D) strain for the detection of ischemia during dobutamine stress echocardiography (DSE). BACKGROUND Evaluation of abnormalities of left ventricular (LV) function from wall thickening during DSE is unsatisfactory and requires a high level of expertise. METHODS In 10 open-chest anesthetized pigs, myocardial deformation was studied before and during dobutamine infusion, under control and ischemic conditions produced by various degrees of coronary artery constriction: 2 of nonflow-limiting stenoses (NFLS) of increasing severity reducing left anterior descending artery hyperemic flow by 40% and 70% and 2 flow-limiting stenoses (FLS) reducing resting coronary flow by 25% and 50%. Agreement between 2D strain echocardiography and sonomicrometry (reference method) was evaluated by linear regression and Bland-Altman analysis. RESULTS Good correlation and agreement were observed between 2-dimensional strain and sonomicrometry at rest and during dobutamine infusion; longitudinal strain: r = 0.77, p < 0.001 and r = 0.80, p < 0.001; radial strain: r = 0.57, p < 0.05 and r = 0.63, p < 0.05; and circumferential strain: r = 0.74, p < 0.001 and r = 0.58, p < 0.001. Circumferential and longitudinal strains in the risk area were significantly decreased at rest in the presence of FLS and during dobutamine infusion in the presence of NFLS. By contrast, radial strain was significantly decreased in the presence of severe FLS only during dobutamine infusion. CONCLUSIONS The 2D strain provides accurate assessment of LV regional function. Evaluation of circumferential and longitudinal strains during DSE has real potential for quantitative evaluation of LV deformation in the routine assessment of ischemia.

Thrombosis of prosthetic heart valves: diagnosis and therapeutic considerations

Prosthetic valve thrombosis (PVT) is a rare but serious complication of valve replacement, most often encountered with mechanical prostheses. The significant morbidity and mortality associated with this condition warrants rapid diagnostic evaluation. However, diagnosis can be challenging, mainly because of variable clinical presentations and the degree of valvular obstruction. Cinefluoroscopy (for mechanical valves) and transthoracic and transoesophageal echocardiography represent the main diagnostic procedures. Although surgical treatment is usually preferred in cases of obstructive PVT, optimal treatment remains controversial. The different therapeutic modalities available for PVT (heparin treatment, fibrinolysis, surgery) will be largely influenced by the presence of valvular obstruction, by valve location (left- or right-sided), and by clinical status. Hence, treatment of an obstructive left-sided PVT will differ from that of non-obstructive or right-sided PVT. The purpose of this article is to review the physiopathology, diagnosis and treatment of PVT and to provide recommendations for management. ### Mechanical valve thrombosis The incidence of obstructive PVT for mechanical valves varies between 0.3–1.3% patient years.1 Thromboembolic complications, including systemic emboli, are more frequent and occur at a rate of 0.7–6% patient years. Non-obstructive PVT is a relatively frequent finding in the postoperative period,2 with a reported incidence as high as 10% in recent transoesophageal echocardiography (TOE) studies. Although these are usually small non-obstructive thrombi, they underline the necessity of optimal anticoagulation in the postoperative period. According to a series of surgical interventions for PVT, the first postoperative year is marked by a 24% incidence of thrombosis, with a stable incidence between the second to fourth years of approximately 15%, with a subsequent decrease thereafter.3 ### Bioprosthetic valve thrombosis Thrombosis of a bioprosthetic valve4 is a rare occurrence when compared to mechanical prostheses. Bioprosthetic PVT is usually diagnosed in the early postoperative period, when endothelialisation of the suture zone is not yet complete. Hence, this has led …

Successful Irrigated-Tip Catheter Ablation of Atrial Flutter Resistant to Conventional Radiofrequency Ablation

BACKGROUND Catheter ablation of typical right atrial flutter is now widely performed. The best end point has been demonstrated to be bidirectional isthmus block. We investigated the use of irrigated-tip catheters in a small subset of patients who failed isthmus ablation with conventional radiofrequency (RF) ablation. METHODS AND RESULTS Of 170 patients referred for ablation of common atrial flutter, conventional ablation of the cavotricuspid isthmus with >21 applications failed to create a bidirectional block in 13 (7.6%). An irrigated-tip catheter ablation was performed on identified gaps in the ablation line according to a protocol found to be safe in animals: a moderate flow rate of 17 mL/min and temperature-controlled (target, 50 degrees C) RF delivery with a power limit of 50 W. Bidirectional isthmus block was achieved in 12 patients by use of a mean delivered power of 40+/-6 W with a single application in 6 patients and 2 to 6 applications in the other 6. No side effects occurred during or after the procedure. CONCLUSIONS Irrigated-tip catheter ablation is safe and effective for achieving cavotricuspid isthmus block when conventional RF energy has failed.

Early and long-term (one-year) effects of the association of aspirin and oral anticoagulant on thrombi and morbidity after replacement of the mitral valve with the St. Jude medical prosthesis: a clinical and transesophageal echocardiographic study.

OBJECTIVES The aim of the study was to test the value of low dose aspirin associated with standard oral anticoagulants (OAC) after mechanical mitral valve replacement (MMRV) to reduce strands, thrombi and thromboembolic events. BACKGROUND Strands and thrombi are thought to increase the risk of embolic events after MMVR, particularly in the immediate postoperative period. METHODS Two hundred twenty-nine patients were prospectively recruited: 109 patients (group A+) were randomly assigned to aspirin (200 mg per day) with OAC and 120 patients (group A-) to OAC alone (international normalized ratio 2.5 to 3.5). All patients were subjected to multiplane transesophageal echocardiography at nine days and five months and were followed up for one year. RESULTS At nine days and five months, there was a high and comparable incidence of strands in the two groups (group A+: 44%, 58%; group A-: 49%, 63%). However, the incidence of nonobstructive periprosthetic valve thrombi was significantly lower in group A+ at 9 days: 5% versus 13%, p = 0.03. Total thromboembolic events were reduced in group A+ (9% vs. 25%, p = 0.004) although there was an increased incidence of gastrointestinal hemorrhage (7% vs. 0%). Overall mortality was 9% in group A+ and 4% in group A-. Valve-related events were similar in both groups. Early thrombi, but not strands, were associated with higher morbidity, especially thromboembolic events (30% vs. 13%, p = 0.003). CONCLUSIONS One year after MMVR, the association of aspirin with OAC reduced thrombi and thromboembolic events, but not morbidity, due to an increase in hemorrhagic complications.

Pacemaker Endocarditis: Clinical Features and Management of 60 Consecutive Cases

Background: The incidence of endocarditis related to pacemakers is increasing, while the diagnosis and management remain difficult. The objective of this study was to evaluate the clinical features and management of endocarditis after implantation of pacemakers (PM) or cardioverter defibrillators (ICD).

Interventricular and intra-left ventricular electromechanical delays in right ventricular paced patients with heart failure: implications for upgrading to biventricular stimulation

Objective: To correlate, in patients with right ventricular pacing (RVP), the QRS width with electromechanical variables assessed by pulsed Doppler tissue imaging echocardiography. Secondly, to find reliable parameters for selecting RVP patients who would respond to biventricular pacing (BVP). Methods: 26 randomly selected control patients with RVP (mean (SD) ejection fraction 74 (3)%) (group A) were matched on sex and age criteria with 16 RVP patients with drug resistant heart failure (mean (SD) ejection fraction 27 (5)%) (group B). All patients were pacemaker dependent and all underwent pulsed Doppler tissue imaging echocardiography. This technique provided the intra-left ventricular (LV) electromechanical delay and the interventricular electromechanical delay. The Gaussian curve properties of data from group A patients provided the normal range of ECG and echographic parameters. Design: Prospective study. Setting: University hospital (tertiary referral centre). Results: Data from the control group showed that an interventricular electromechanical delay or an intra-LV electromechanical delay > 50 ms would identify patients with a significantly abnormal ventricular mechanical asynchrony (p < 0.05). In the same manner, a QRS width > 190 ms was considered significantly larger in group B patients (p < 0.05) than in controls. In Group B patients, there was no correlation between the QRS width and the interventricular electromechanical delay (r  =  −0.23, NS) or the intra-LV electromechanical delay (r  =  0.19, NS). Seven group B patients (44%) were misclassified by ECG criteria for ventricular mechanical asynchrony identification: four patients (25%) had a QRS width similar to that of controls but with a significantly prolonged intra-LV electromechanical delay and interventricular electromechanical delay; and three patients (19%) had a QRS width significantly larger than that in controls but without significant ventricular mechanical asynchrony. Conclusions: The QRS width is not a reliable tool to identify RVP patients with ventricular mechanical asynchrony. In RVP patients, an interventricular electromechanical delay or intra-LV electromechanical delay > 50 ms reflects a significant ventricular mechanical asynchrony and should be required to select patients for upgrading to BVP.

Evaluation of Global Left Ventricular Systolic Function Using Three-Dimensional Echocardiography Speckle-Tracking Strain Parameters

BACKGROUND The aim of this study was to evaluate the capacity and reproducibility of three-dimensional echocardiographic (3DE) strain parameters in the assessment of global left ventricular (LV) systolic function. METHODS A total of 128 subjects with differing LV ejection fractions were investigated using two-dimensional echocardiographic (2DE) and 3DE strains. Three-dimensional echocardiographic strain allows obtaining longitudinal, circumferential, radial, and area strains. First, values of global longitudinal strain (GLS) by 2DE and 3DE speckle-tracking analyses were compared. Thereafter, 3DE strain parameters were correlated with LV ejection fraction and indexed output. Last, the variability of 3DE versus 2DE strain measurements as well as recorded time of analysis were assessed. RESULTS After excluding 21 patients for insufficient image quality, four for arrhythmia, two for severe valvular disease, and one for severe dyspnea, the final population consisted of 100 patients. Comparison between 2DE and 3DE GLS revealed high correspondence (r = 0.91, y = 1.04x - 0.71) and mean error measurement of -1.3% (95% confidence interval, -5.7 to 3.2). Among strain parameters, global area strain exhibited the highest correlation with LV ejection fraction (y = -1.65 + 10.4, r = -0.92, P < .001). Intraobserver measurement variability proved acceptable: 8% for GLS (vs 6% on 2DE analysis), 7% for circumferential strain (vs 15% on 2DE analysis), 7% for radial strain (vs 33% on 2DE analysis), and 5% for global area strain. The mean error between two measurements was lower with 3DE than 2DE analysis for circumferential and radial strains but similar for GLS. The mean time of analysis was of 117 ± 16 sec for 3DE analysis, which was 25% less than for 2DE analysis (P < .001). CONCLUSIONS Of all strain parameters, new 3DE area strain correlated best with common LV systolic function parameters and is thus the most promising approach, while all 3DE strain markers exhibited good reproducibility.