Francisco Buendía

Cardiac magnetic resonance imaging at 1.5 T in patients with cardiac rhythm devices

AIMS Recent studies suggest that non-cardiac magnetic resonance imaging (MRI) scanning can be performed safely in selected cardiac rhythm device patients. However, little is known about the safety of performing specific cardiac MRI in this setting. We sought to determine the feasibility of cardiac MRI in patients with pacemakers (PMs) or implantable cardioverter-defibrillators (ICDs). METHODS AND RESULTS Thirty-eight patients underwent a total of 39 (8 ICDs and 31 PM) cardiac MRI examinations at 1.5 T using usual protocols without specific absorption rate (SAR) restrictions. Nine PM-dependent patients were included. All devices were interrogated before and immediately after MRI. During the scan, pacing mode was programmed to asynchronous for PM-dependent patients whereas ICDs were programmed to a monitor-only mode. All devices were functioning appropriately after cardiac MRI. Comparison of device parameters obtained before and immediately after MRI revealed no significant changes in pacing threshold, lead impedance, battery status, or sensing signal amplitude. Neither clinical events nor patient complaints were reported. Significant imaging artefacts were present on 11 of 39 scans (28.2%). These artefacts were significantly more frequent in ICDs (8 of 8, 100%) vs. PMs (3 of 31, 9.7%) (P < 0.001). Diagnostic questions were answered in 92.3% of the cases, with just three pronounced artefacts preventing an adequate diagnosis in three ICD patients. CONCLUSIONS Our results suggest that cardiac MRI may be performed safely in appropriately selected patients with close monitoring during the scan without limitation of peak SAR level using several precautionary measures. Image artefacts were more frequent in ICD patients.

Progression of renal dysfunction in cardiac transplantation after the introduction of everolimus in the immunosuppressive regime.

The aim of this study was to analyze, in heart transplant patients, if renal function improvement after cyclosporine replacement by everolimus persists at the middle term and its predictors. We studied prospectively 56 patients in whom conversion was consecutively made. Forty-five patients completed the follow-up period. Significant improvement was observed at 6 and 12 months in plasma creatinine levels (1.92±0.7 vs. 1.67±0.6 and 1.69±0.6 mg/dL; P=0.047) and glomerular filtration rate (43.9±17 vs. 52.5±23 and 51.3±22.3 mL/min; P=0.004). Glomerular filtration rate increased in 32 patients (71%). Baseline characteristics comparison showed a lower percentage of patients with smoking history and new onset diabetes in responders group, but only previous smoking was shown as independent factor (Exp B: 0.083; 95% confidence interval: 0.010–0.793; P=0.024). No differences regarding age, gender, body mass index, disease leading to transplantation, time between transplantation and replacement, cardiovascular risk factors, lipid levels, and hematologic parameters were found.

Resonancia magnética nuclear en pacientes portadores de dispositivos de estimulación cardiaca

La resonancia magnetica esta actualmente contraindicada a los pacientes portadores de dispositivos de estimulacion cardiaca. Ante la necesidad de concretar los riesgos potenciales derivados de esta situacion, surgio este estudio. De forma prospectiva, se evaluaron parametros clinicos, electricos y tecnicos antes y despues de la realizacion de la prueba en 33 pacientes (5 desfibriladores automaticos implantables, 28 marcapasos), en los que se considero clinicamente indispensable realizarla. No se apreciaron complicaciones clinicas. Se detectaron dos casos de fallo temporal de telemetria, dos errores de deteccion durante la exploracion y una respuesta de seguridad en un marcapasos a frecuencia magnetica y salida maxima. No hubo limitaciones tecnicas en la adquisicion de imagenes ni alteraciones permanentes del funcionamiento de los dispositivos de estimulacion cardiaca.

Nuclear Magnetic Resonance Imaging in Patients With Cardiac Pacing Devices

Currently, nuclear magnetic resonance imaging is contraindicated in patients with a pacemaker or implantable cardioverter-defibrillator. This study was carried out because the potential risks in this situation need to be clearly defined. This prospective study evaluated clinical and electrical parameters before and after magnetic resonance imaging was performed in 33 patients (five with implantable cardioverter-defibrillators and 28 with pacemakers). In these patients, magnetic resonance imaging was considered clinically essential. There were no clinical complications. There was a temporary communication failure in two cases, sensing errors during imaging in two cases, and a safety signal was generated in one pacemaker at the maximum magnetic resonance frequency and output level. There were no technical restrictions on imaging nor were there any permanent changes in the performance of the cardiac pacing device.

Valor pronóstico de la tasa de filtración glomerular al año del trasplante cardiaco

Introduccion y objetivos Uno de los problemas mas relevantes tras el trasplante cardiaco es el desarrollo de insuficiencia renal. La heterogeneidad en su definicion hace que la estimacion de su prevalencia sea variable. Por otro lado, su impacto en la mortalidad no ha sido suficientemente estudiado. El objetivo fue evaluar la relacion entre la tasa de filtracion glomerular al ano (TFG) y la mortalidad en el seguimiento. Metodos Se analizo la TFG de 316 pacientes vivos al ano del trasplante mediante la formula abreviada Modification of Diet in Renal Disease Study. Se clasificaron en tres grupos segun su TFG ( Resultados No hubo diferencias en el numero de rechazos ni infecciones durante el primer ano en los tres grupos. En el seguimiento medio (6,3 anos) fallecio el 74% de los pacientes con TFG Conclusiones La disfuncion grave de la funcion renal al ano es un predictor independiente de mortalidad por todas las causas a largo plazo en el paciente con trasplante cardiaco.

Prognostic Value of Glomerular Filtration Rate 1 Year After Heart Transplantation

INTRODUCTION AND OBJECTIVES The development of renal failure is one of the most important problems after heart transplantation (HT), but the wide range of definitions means that estimates of its prevalence vary considerably. Furthermore, its impact on mortality has not been adequately studied. The objective was to investigate the relationship between the glomerular filtration rate (GFR) 1 year after transplantation and mortality during follow-up. METHODS The GFR was determined in 316 patients still living 1 year after transplantation using the abbreviated Modification of Diet in Renal Disease Study formula. Patients were divided into three groups according to GFR (i.e. <30, 30-59 and > or =60 mL/min per 1.73 m2) and pretransplant variables and rejection and infection rates within the first year were analyzed. The association between GFR at 1 year and mortality during follow-up was evaluated and reasons for the association were examined. RESULTS There was no difference in the number of rejections or infections in the first year between the three groups. During a mean follow-up period of 6.3 years, 74% of patients with a GFR <30 mL/min per 1.73 m2 died, compared with 24% and 30% of those with a GFR > or =60 and 30-59 mL/min per 1.73 m2, respectively. Survival analysis (i.e. Cox regression analysis) demonstrated a significant difference between patients with a GFR <30 mL/min per 1.73 m2 and other patients (P< .001). A very low GFR at 1 year was the only independent predictor that remained statistically significant on multivariate analysis (hazard ratio =2.87; 95% confidence interval, 1.52-5.41). CONCLUSIONS Severe renal dysfunction at 1 year was an independent predictor of long-term all-cause mortality in heart transplant patients.

Myocardial and lymphocytic expression of eNOS and nNOS before and after heart transplantation: relationship to clinical status.

AIMS The present study investigates the expression and clinical relevance of the constitutive NO synthases in heart and peripheral blood mononuclear cells (PBMCs) obtained from heart failure patients. MAIN METHODS mRNA and protein levels (qRT-PCR and immunoblot) of eNOS and nNOS were determined in: i) Left ventricle (LV, n=4) and PBMCs (n=10) from healthy donors; ii) LV, right ventricle (RV) and PBMCs of heart failure (HF) patients (n=32); and iii) biopsies and PBMCs of the HF patients after cardiac transplant (n=15). KEY FINDINGS Expression of constitutive NOS isoforms in heart exhibits wide variability in HF patients, but this variability was not related to aetiology, disease severity, concomitant pathologies or drug regimes. A significantly increased eNOS expression was found in LV from HF patients without vs. with pulmonary hypertension. Overall, higher eNOS expression in this chamber was associated with lower pulmonary arterial pressure. Furthermore, a higher eNOS expression in HF is associated with smaller LV diameter, whereas, a higher post-transplant eNOS expression is related to greater cardiac distensibility. In the RV, nNOS increased after transplant. The positive correlation found between the nNOS expression in the LV of HF patients and the cardiac index suggests a role for this isoform in facilitating cardiac work. A decreased expression of eNOS was observed in PBMCs from HF patients vs. healthy donors, which recovers after transplant. SIGNIFICANCE A selective up-regulation of the cardiac expression of each NOS isoform in the failing heart, which is not mirrored by PBMCs, is related to an improved health status.

Real-world Data on the Efficacy of Vernakalant for Pharmacological Cardioversion in Patients With Recent-onset Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia and the reason for many emergency department (ED) visits. The treatment of AF in the ED is a challenge the recommended approach is conversion to sinus rhythm (SR). Rhythm control is normally achieved with propafenone and flecainide in patients without structural heart disease and with amiodarone in those with structural heart disease. Nevertheless, given the difficulty of ruling out a history of structural heart disease, intravenous amiodarone is frequently used in the ED, although it is not considered the best choice for conversion to SR. Vernakalant is a new antiarrhythmic multichannel blocking agent intended for intravenous administration with a short half-life (2 hours) and high selectivity for atrial cardiomyocytes. It is recommended for conversion in patients with AF of less than 7 days duration, moderate structural heart disease, and the only contraindications are severe hypotension (< 100 mmHg), heart failure (New York Heart Association functional class III-IV), severe aortic stenosis, or acute coronary syndrome within 30 days.Given the benefits of the drug, we began to use it in the our ED according to the recommendations on dosage and infusion times and the summary of the product characteristics.We present our experience of the first 52 consecutive administrations of vernakalant between January 2014 and December 2015. We collected information on risk factors, the presence of structural heart disease, duration of AF, time from start of infusion to conversion to SR, adverse effects, and length of stay in the ED. In total, 47 patients were included in the study. Of these patients, 5 received vernakalant during 2 ED visits, making a total of 52 treatments. Table 1 shows the patients’ baseline characteristics. Conversion was achieved in 45 patients (86%) and a second vernakalant infusion was needed in only 8 patients. In addition, the time to conversion to SR was rapid (mean, 12.5 minutes; range, 1-115; median, 8), which led to shorter stays in the ED (mean, 5.3 [2-18] hours). Five patients experienced mild adverse events: 1 patient had sustained ventricular tachycardia (vernakalant infusion was maintained with subsequent conversion to SR); 2 patients had self-limiting cough and nausea; 1 patient had dysgeusia; and 1 patient had self-limiting atrial flutter. Regarding its use with other antiarrhythmic agents, conversion was attempted with amiodarone in 1 patient, without success, and at 4 hours an infusion of vernakalant achieved conversion within a few minutes. Another patient received background therapy with flecainide to which vernakalant was added without incident. Vernakalant was used more frequently with beta-blockers (10 patients) than with dihydropyridine calcium antagonists (1 patient). Binary logistic regression analysis was used identify predictors of success in conversion to SR with vernakalant (Table 2). Elevated heart rate on the first electrocardiogram at arrival was independently associated with successful conversion, whereas the presence of structural heart disease was associated with low success rates. This study demonstrates the efficacy of vernakalant in achieving rapid and safe conversion to SR. Only 5 patients experienced mild transient adverse effects and the mean conversion time was 12.5 minutes, which allowed patients to be discharged from the ED in just over 5 hours. The results of our series are better than those of pivotal trials of vernakalant, which together show an efficacy of 51% although, as in our series, conversion was rapid and safe. Nevertheless, the results of its use in clinical practice are very similar to ours. Demonstrated efficacy rates of 86% to 93% and of 66% have been published by Conde et al and Mochalina et al, respectively. The analysis of predictors of success showed that elevated heart rate was associated with the highest success rates. However, in line with the findings of Costabel al, the presence of structural heart disease was nonsignificantly associated with low success rates. This finding may explain why the results of registries are better than those of pivotal trials, given that the proportion of patients with structural heart disease is lower in real-world registries. The main limitations of this study are its single-center design and its small sample size, which may have decreased its statistical power to identify predictors of successful conversion. In addition, the patients were relatively healthy, had a low prevalence of structural heart disease, and had a first AF episode. In contrast, the percentage of patients with a first AF episode was lower in clinical trials and other published real-world studies. In conclusion, vernakalant is an efficacious, rapidly acting, and safe drug for conversion of AF to SR. The main limitations to its

Value of the Electrocardiogram as a Predictor of Right Ventricular Dysfunction in Patients With Chronic Right Ventricular Volume Overload

INTRODUCTION AND OBJECTIVES Pulmonary regurgitation is a common complication in patients with repaired tetralogy of Fallot or congenital pulmonary stenosis. Electrocardiographic variables have been correlated with parameters used to evaluate right ventricular function. We aimed to analyze the diagnostic value of the width and fragmentation of the electrocardiogram in the identification of patients with right ventricular dysfunction and/or dilation. METHODS We selected 107 consecutive patients diagnosed with severe pulmonary insufficiency after repair of pulmonary stenosis or tetralogy of Fallot. The tests included electrocardiography, echocardiography, and magnetic resonance. Each electrocardiogram was analyzed manually to measure QRS duration. We defined QRS fragmentation as the presence of low-voltage waves in the terminal portion of the QRS complex in at least 2 contiguous leads. RESULTS We found a significant negative correlation between QRS width and right ventricular function, as well as a positive correlation with right ventricular volume. The receiver operating characteristic curve indicated a cut-off point for QRS width of 140ms, which showed good sensitivity for a diagnosis of right ventricular dilation (> 80%) and dysfunction (> 95%). In logistic regression models, a QRS duration > 140ms was found to be the only independent predictor of right ventricular dilation and dysfunction. CONCLUSIONS Electrocardiography is a rapid, widely available, and reproducible tool. QRS width constitutes an independent predictor of the presence of right ventricular dilation and dysfunction. This study is the first to provide a cutoff value for QRS width to screen for right ventricle involvement.

Electrocardiogram–electrogram desynchronization while using radiofrequency wandless telemetry during implantation of an implantable cardioverter defibrillator

A 57-year-old man was referred for implantation of a dual-chamber implantable cardioverter defibrillator as secondary prevention of sudden cardiac death. During implantation, wandless telemetry was used to establish communication with the device. We describe an episode of electrocardiogram–electrogram desynchronization using this novel technology and discuss the possible clinical implications.