Assessment of Blood Flow Transport in the Left Ventricle Using Ultrasound. Validation Against 4-D Flow Cardiac Magnetic Resonance.

Four-dimensional flow cardiac magnetic resonance (CMR) is the reference technique for analyzing blood transport in the left ventricle (LV), but similar information can be obtained from ultrasound. We aimed to validate ultrasound-derived transport in a head-to-head comparison against 4D flow CMR. In five patients and two healthy volunteers, we obtained 2D + t and 3D + t (4D) flow fields in the LV using transthoracic echocardiography and CMR, respectively. We compartmentalized intraventricular blood flow into four fractions of end-diastolic volume: direct flow (DF), retained inflow (RI), delayed ejection flow (DEF) and residual volume (RV). Using ultrasound we also computed the properties of LV filling waves (percentage of LV penetration and percentage of LV volume carried by E/A waves) to determine their relationships with CMR transport. Agreement between both techniques for quantifying transport fractions was good for DF and RV (Ric [95% confidence interval]: 0.82 [0.33, 0.97] and 0.85 [0.41, 0.97], respectively) and moderate for RI and DEF (Ric= 0.47 [-0.29, 0.88] and 0.55 [-0.20, 0.90], respectively). Agreement between techniques to measure kinetic energy was variable. The amount of blood carried by the E-wave correlated with DF and RV (R = 0.75 and R = 0.63, respectively). Therefore, ultrasound is a suitable method for expanding the analysis of intraventricular flow transport in the clinical setting.

Automatic quality electrogram assessment improves phase-based reentrant activity identification in atrial fibrillation.

Identification of reentrant activity driving atrial fibrillation (AF) is increasingly important to ablative therapies. The goal of this work is to study how the automatically-classified quality of the electrograms (EGMs) affects reentrant AF driver localization. EGMs from 259 AF episodes obtained from 29 AF patients were recorded using 64-poles basket catheters and were manually classified according to their quality. An algorithm capable of identifying signal quality was developed using time and spectral domain parameters. Electrical reentries were identified in 3D phase maps using phase transform and were compared with those obtained with a 2D activation-based method. Effect of EGM quality was studied by discarding 3D phase reentries detected in regions with low-quality EGMs. Removal of reentries identified by 3D phase analysis in regions with low-quality EGMs improved its performance, increasing the area under the ROC curve (AUC) from 0.69 to 0.80. The EGMs quality classification algorithm showed an accurate performance for EGM classification (AUC 0.94) and reentry detection (AUC 0.80). Automatic classification of EGM quality based on time and spectral signal parameters is feasible and accurate, avoiding the manual labelling. Discard of reentries identified in regions with automatically-detected poor-quality EGMs improved the specificity of the 3D phase-based method for AF driver identification.

Noninvasive Assessment of Complexity of Atrial Fibrillation: Correlation With Contact Mapping and Impact of Ablation.

BACKGROUND: It is difficult to noninvasively phenotype atrial fibrillation (AF) in a way that reflects clinical end points such as response to therapy. We set out to map electrical patterns of disorganization and regions of reentrant activity in AF from the body surface using electrocardiographic imaging, calibrated to panoramic intracardiac recordings and referenced to AF termination by ablation. METHODS: Bi-atrial intracardiac electrograms of 47 patients with AF at ablation (30 persistent, 29 male, 63±9 years) were recorded with 64-pole basket catheters and simultaneous 57-lead body surface ECGs. Atrial epicardial electrical activity was reconstructed and organized sites were invasively and noninvasively tracked in 3-dimension using phase singularity. In a subset of 17 patients, sites of AF organization were targeted for ablation. RESULTS: Body surface mapping showed greater AF organization near intracardially detected drivers than elsewhere, both in phase singularity density (2.3±2.1 versus 1.9±1.6; P=0.02) and number of drivers (3.2±2.3 versus 2.7±1.7; P=0.02). Complexity, defined as the number of stable AF reentrant sites, was concordant between noninvasive and invasive methods (r2=0.5; CC=0.71). In the subset receiving targeted ablation, AF complexity showed lower values in those in whom AF terminated than those in whom AF did not terminate (P<0.01). CONCLUSIONS: AF complexity tracked noninvasively correlates well with organized and disorganized regions detected by panoramic intracardiac mapping and correlates with the acute outcome by ablation. This approach may assist in bedside monitoring of therapy or in improving the efficacy of ongoing ablation procedures.

Clinical assessment of intraventricular blood transport in patients undergoing cardiac resynchronization therapy.

In the healthy heart, left ventricular (LV) filling generates different flow patterns which have been proposed to optimize blood transport by coupling diastole and systole. This work presents a novel image-based method to assess how different flow patterns influence LV blood transport in patients undergoing cardiac resynchronization therapy (CRT). Our approach is based on solving the advection equation for a passive scalar field from time-resolved blood velocity fields. Imposing time-varying inflow boundary conditions for the scalar field provides a straightforward method to distinctly track the transport of blood entering the LV in the different filling waves of a given cardiac cycle, as well as the transport barriers which couple filling and ejection. We applied this method to analyze flow transport in a group of patients with implanted CRT devices and a group of healthy volunteers. Velocity fields were obtained using echocardiographic color Doppler velocimetry, which provides two-dimensional time-resolved flow maps in the apical long axis three-chamber view of the LV. In the patients under CRT, the device programming was varied to analyze flow transport under different values of the atrioventricular conduction delay, and to model tachycardia (100 bpm). Using this method, we show how CRT influences the transit of blood inside the left ventricle, contributes to conserving kinetic energy, and favors the generation of hemodynamic forces that accelerate blood in the direction of the LV outflow tract. These novel aspects of ventricular function are clinically accessible by quantitative analysis of color-Doppler echocardiograms.

Immediate post-procedure bridging with unfractioned heparin versus low molecular weight heparin in patients undergoing radiofrequency ablation for atrial fibrillation with an interrupted oral anticoagulation strategy.

PURPOSE: Many centers perform catheter ablation for atrial fibrillation (AF) with periprocedural interruption of oral vitamin K antagonists. In this scenario, the optimal post-procedural anticoagulation strategy is still under debate. We sought to compare the incidence of major complications associated with post-procedural use of low molecular weight heparin (LMWH) versus unfractioned heparin (UFH) as a bridge to reinitiation of oral anticoagulation after an AF ablation procedure. METHODS: We retrospectively reviewed medical history data of all patients undergoing catheter ablation for AF at three Spanish referral centers between January 2009 and January 2014. A total of 702 patients were included in the analysis. We compared the incidence of major complications (a combination of major bleeding and thromboembolic events) between patients receiving UFH (291) and those receiving LMWH (411) after the procedure. RESULTS: The overall incidence of major complications was 4.1%, including five thromboembolic events (0.7%) and 24 major bleeding events (3.4%), with no significant differences in patients treated with LMWH vs. UFH (2.9 vs. 4.1%; P = NS). The presence of peripheral vascular disease emerged as the only independent predictor of major complications (adjusted odds ratio (OR) 9.1; confidence interval (CI) 95% 1.7-49.3; P < 0.01). CONCLUSIONS: Immediate post-procedural bridging with UFH or with LMWH are equally safe strategies in patients undergoing catheter ablation for AF in whom oral anticoagulation is interrupted for the procedure. Due to its greater simplicity of use, LMWH may be the preferred option. The presence of peripheral vascular disease is a potent predictor of major post-procedural complications.

Relationship between time to invasive assessment and clinical outcomes of patients undergoing an early invasive strategy after fibrinolysis for ST-segment elevation myocardial infarction: a patient-level analysis of the randomized early routine invasive clinical trials.

OBJECTIVES: This study investigated the relationship between time to invasive assessment and outcomes among ST-segment elevation myocardial infarction patients randomized to early angiography after fibrinolysis. BACKGROUND: The optimal timing of coronary angiography after fibrinolysis and the association with clinical outcomes is uncertain. METHODS: Patient-level data from 6 randomized trials, with a median time to angiography <12 h after fibrinolysis, were pooled. The primary endpoint was 30-day death or reinfarction. The key secondary endpoint was in-hospital major bleeding. The relationship between fibrinolysis to angiography time and symptom onset to angiography time with outcomes was studied using 2- and 4-h intervals, respectively, and in multivariable models. RESULTS: Among 1,238 patients, the median fibrinolysis to angiography time was 165 min, and the median symptom onset to angiography time was 5.33 h. The primary and key secondary endpoints occurred in 5.7% and 4.7%, respectively. These main endpoints did not vary significantly with increasing fibrinolysis to angiography time. Early angiography (<2 h) after fibrinolysis was not associated with increased bleeding. Recurrent ischemia increased with increasing fibrinolysis to angiography time (3.7% to 7.9%, p for trend = 0.02). Thirty-day and 1-year death/reinfarction and 30-day recurrent ischemia increased significantly with increasing symptom onset to angiography time. Neither fibrinolysis to angiography time nor symptom onset to angiography time was an independent predictor of the primary endpoint. Only symptom onset to angiography time was an independent predictor of 1-year death/reinfarction (hazard ratio: 1.07, 95% confidence interval: 1.02 to 1.12, p = 0.01). CONCLUSIONS: Very early angiography (<2 h) after fibrinolysis was not associated with an increased risk of 30-day death/reinfarction or in-hospital major bleeding, and angiography within 4 h after fibrinolysis was associated with reduced 30-day recurrent ischemia. A shorter symptom onset to angiography time (<4 h) was associated with reduced 30-day and 1-year death/reinfarction and 30-day recurrent ischemia. In the current environment of regional networks of 24/7 primary percutaneous coronary intervention (PCI) centers, the clinical implication of these findings is that patients initially treated with fibrinolysis should also be promptly transferred to the nearest PCI center for immediate angiography and PCI. (Early Percutaneous Coronary Intervention [PCI] After Fibrinolysis Versus Standard Therapy in ST Segment Elevation Myocardial Infarction [STEMI] Patients; NCT01014182).

Safety of Outpatient Implantation of the Implantable Cardioverter-defibrillator.

INTRODUCTION AND OBJECTIVES: Strategies are needed to reduce health care costs and improve patient care. The objective of our study was to analyze the safety of outpatient implantation of cardioverter-defibrillators. METHODS: A retrospective study was conducted in 401 consecutive patients who received an implantable cardioverter-defibrillator between 2007 and 2012. The rate of intervention-related complications was compared between 232 patients (58%) whose implantation was performed in the outpatient setting and 169 patients (42%) whose intervention was performed in the inpatient setting. RESULTS: The mean age (standard deviation) of the patients was 62 (14) years; 336 (84%) were male. Outpatients had lower left ventricular ejection fraction and a higher percentage had an indication for primary prevention of sudden death, compared to inpatients. Only 21 outpatients (9%) required subsequent hospitalization. The rate of complications until the third month postimplantation was similar for outpatients (6.0%) and inpatients (5.3%); P = .763. In multivariate analysis, only previous anticoagulant therapy was related to the presence of complications (odds ratio = 3.2; 95% confidence interval, 1.4-7.4; P < .01), mainly due to an increased rate of pocket hematomas. Each outpatient implantation saved approximately €735. CONCLUSIONS: Outpatient implantation of implantable cardioverter-defibrillators is safe and reduces costs. Close observation is recommended for patients receiving chronic anticoagulation therapy due to an increased risk of complications.

Determinants of long-term survival in patients hospitalized for heart failure.

BACKGROUND AND OBJECTIVES: Current models used to stratify patients with heart failure are complex, difficult to use, and limited by short follow-up and patient selection. Our aim was to determine predictors of long-term survival in patients hospitalized for heart failure and to develop a simple mortality risk score to estimate long-term mortality. METHODS: We prospectively followed up, during 10 years after hospitalization, 701 patients with confirmed heart failure from the HOLA (Heart failure: Observation of Local Admissions) registry. RESULTS: Mean age was 72.4 +/- 11.7 years; 45% were men. During follow-up, 465 patients died and 5 underwent heart transplantation. A total of 231 patients (33%) were alive and transplant-free at the end of follow-up (5.2 +/- 4.2 years). Median survival was 3.2 years. Multivariate analysis showed that six variables (age, previous renal disease, previous stroke, chronic obstructive pulmonary disease, left ventricular ejection fraction and aortic stenosis) were independent predictors of shorter survival time. By dichotomizing these variables, we obtained six factors with similar predictive values (hazard ratio between 1.5 and 2.0). A risk score for mortality was developed using these predictors by assigning 1 point to each and adding the total for each patient. Median survival for patients with 0, 1, 2, and 3 or more points were 6.5, 5.5, 3.3, and 1.7 years, respectively. One-year mortality rates were 15, 20, 28, and 49%, respectively. CONCLUSION: The prognosis of patients hospitalized with heart failure is highly variable. A simple risk score, based on six variables readily obtainable on admission can effectively stratify patients according to their predicted mortality.

Assessment of inappropriate hospital stays in a cardiology department.

One of the fundamental ways of increasing hospital efficiency is to ensure that unnecessary hospital stays are avoided. To date, no study on this topic has been published by any cardiology department in Spain. We performed a retrospective observational analytical study to determine the rate of unnecessary hospital stays. Data were collected in accordance with the Appropriateness Evaluation Protocol (AEP). The rate of inappropriate stays was 27 per 100 patient-days. Multivariate analysis showed that the factors associated with inappropriate stays were older age-group, stays longer than 7 days, and days during the last third of the stay. The most frequent causes of inappropriate stays were delays in performing diagnostic and therapeutic procedures and stays for procedures that could have been performed without hospital admission.

Noninvasive assessment of the right ventricular filling pressure gradient.

BACKGROUND: The physiological basis of right ventricular (RV) diastolic function remains incompletely studied in humans. The driving force responsible for RV filling, the pressure gradient along the RV inlet from the right atrium to the RV apex, has never been measured in the clinical setting. METHODS AND RESULTS: We validated a method for measuring the RV filling pressure difference (RVFPD) from color Doppler M-mode recordings in 12 pigs undergoing interventions on RV preload, afterload, and lusitropic states (error, -0.1+/-0.4 mm Hg compared with micromanometers; intraclass correlation coefficient, 0.88). Peak early RVFPD correlated directly with mean right atrial pressure and inversely with the time constant of RV relaxation. In 21 patients with dilated cardiomyopathy, the peak RVFPD was 1.0 mm Hg (95% CI, 0.8 to 1.2), significantly lower than in age-matched control subjects (1.4 mm Hg; 95% CI, 1.2 to 1.6). In another population of 19 young healthy volunteers, the peak RVFPD was 2.3 mm Hg (95% CI, 2.0 to 2.6), which was reduced by nitroglycerine and esmolol and was augmented by volume overload and atropine infusions. RVFPD was generated almost exclusively by inertial forces. CONCLUSIONS: For the first time, the RV driving filling force can be accurately measured noninvasively in the clinical setting, and the method is sensitive to detect the effects of preload, chronotropic, and lusitropic states. In patients with dilated cardiomyopathy, the RV filling force is markedly reduced, indicating severely impaired RV relaxation. These findings suggest that this is a useful tool for improving the clinical assessment of RV diastolic function.

Trends and contexts in European cardiology practice for the next 15 years: the Madrid Declaration: a report from the European Conference on the Future of Cardiology, Madrid, 2-3 June 2006.

In the near future, the practice of cardiology in Europe will be strongly influenced by a complex interplay of epidemiological, social, economical, professional, and technological evolving factors. The present report summarizes the conclusions of an expert conference organized by the European Society of Cardiology to discuss the interactions between these phenomena, in an attempt to foresee the potential scenario in which cardiovascular healthcare and research will develop in the near future, and to anticipate solutions to the identified problems.

The role of noninvasive imaging techniques in the assessment of stem cell therapy after acute myocardial infarction.

Stem cell therapy after acute myocardial infarction is a promising therapeutic strategy. Intermediate-sized clinical trials to answer many unanswered questions must be carefully designed and surrogate end points carefully chosen. Moreover, imaging techniques accurate enough to measure surrogate parameters and to make it possible to reduce sample size are needed. The imaging technique of choice in this setting should be capable of tracking the destiny of the stem cells once injected in the heart and of quantifying left ventricular remodelling parameters. This information will be crucial in the design of multicenter, large, randomized trials to assess survival, which can definitively establish the usefulness of this therapeutic strategy.