Safety and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using Magnetic Navigation versus Manual Conventional Ablation: A Propensity-Score Analysis.

INTRODUCTION: Whether or not the potential advantages of using a magnetic navigation system (MNS) translate into improved outcomes in patients undergoing atrial fibrillation (AF) ablation is a question that remains unanswered. METHODS AND RESULTS: In this observational registry study, we used propensity-score matching to compare the outcomes of patients with symptomatic drug-refractory AF who underwent catheter ablation using MNS with the outcomes of those who underwent catheter ablation using conventional manual navigation. Among 1,035 eligible patients, 287 patients in each group had similar propensity scores and were included in the analysis. The primary efficacy outcome was the rate of AF relapse after a 3-month blanking period. At a mean follow-up of 2.6 ± 1.5 years, AF ablation with MNS was associated with a similar risk of AF relapse as compared with manual navigation (18.4% per year and 22.3% per year, respectively; hazard ratio 0.81, 95% CI 0.63-1.05; P = 0.108). Major complications occurred in two patients (0.7%) using MNS, and in six patients (2.1%) undergoing manually navigated ablation (P = 0.286). Fluoroscopy times were 21 ± 10 minutes in the manual navigation group, and 12 ± 9 minutes in the MNS group (P < 0.001), whereas total procedure times were 152 ± 52 minutes and 213 ± 58 minutes, respectively (P < 0.001). CONCLUSIONS: In this propensity-score matched comparison, magnetic navigation and conventional manual AF ablations seem to have similar relapse rates and a similar risk of complications. AF ablations with magnetic navigation take longer to perform but expose patients to significantly shorter fluoroscopy times.

Prognostic Value of a Very Prolonged Asystole during Head-Up Tilt Test.

BACKGROUND: Clinical significance and prognosis of a cardioinhibitory response to head-up tilt (HUT) test with a very prolonged asystole (≥30 seconds) is poorly studied. Our aim was to evaluate the treatment (including pacemaker implantation) and prognosis (syncope recurrence, syncope-related trauma, and overall mortality) of patients with a very prolonged asystole on a HUT test. METHODS AND RESULTS: A retrospective study was conducted in two centers between January 2003 and December 2013 and included a total of 2,263 consecutive HUT tests (sensitized with isosorbide dinitrate) performed in 2,247 patients with syncope of unknown etiology. Cardioinhibitory response with asystole was observed in 149 (6.6%) of these tests (44.3% women, mean age 37 ± 18 years old, 16.1% in the nonpharmacological phase), with a median duration of asystole of 10 (6-19) seconds. Very prolonged asystole (≥30 seconds) was documented in 11 (0.5%) patients (45% women; mean age 40 ± 19 years; only one in the nonpharmacological phase, 9 minutes after HUT). The longest pause lasted 63 seconds. In all patients, avoidance of triggering factors and physical counterpressure maneuvers were recommended. Telephone follow-up was performed: in one patient, fludrocortisone was started; tilt training was conducted in one patient and none received a pacemaker. After a median follow-up of 42 (30-76) months, four patients (36%) had syncopal recurrences, one patient had a syncope-related injury (scalp laceration), and no patient died.

Distinct Substrates of Idiopathic Ventricular Fibrillation Revealed by Arrhythmia Characteristics on Implantable Cardioverter-Defibrillator.

BACKGROUND: Idiopathic ventricular fibrillation (IVF) can be associated with undetected distinct conditions such as microstructural cardiomyopathic alterations (MiCM) or Purkinje (Purk) activities with structurally normal hearts. OBJECTIVE: This study sought to evaluate the characteristics of recurrent VF recorded on implantable defibrillator electrograms, associated with these substrates. METHODS: This was a multicenter collaboration study. At 32 centers, we selected patients with an initial diagnosis of IVF and recurrent arrhythmia at follow-up without antiarrhythmic drugs, in whom mapping demonstrated Purk or MiCM substrate. We analyzed variables related to previous ectopy, sinus rate preceding VF, trigger, and initial VF cycle lengths. Logistic regression with cross validation was used to evaluate the performance of criteria to discriminate Purk or MiCM substrates. RESULTS: Among 95 patients (35 women, age 35 ± 11 years) meeting the inclusion criteria, IVF was associated with MiCM in 41 and Purk in 54 patients. A total of 117 arrhythmia recurrences including 91% VF were recorded on defibrillator. Three variables were mostly discriminant. Sinus tachycardia (≤570 ms) was more frequent in MiCM (35.9% vs 13.4%, P = 0.014) whereas short-coupled (<350 ms) triggers were most frequent in Purk-related VF (95.5% vs 23.1%, P = 0.001), which also had shorter VFCLs (182 ± 15 ms vs 215 ± 24 ms, P < 0.001).The multivariable combination provided the highest prediction (accuracy = 0.93 ± 0.05, range 0.833-1.000), discriminating 81% of IVF substrates with a high probability (>80%). Ectopy were inconsistently present before VF. CONCLUSIONS: Characteristics of arrhythmia recurrences on implantable cardioverter- defibrillator provide phenotypic markers of the distinct and hidden substrates underlying IVF. These findings have significant clinical and genetic implications.

Understanding cardiac myxoma recurrence: a case report.

Recurrence of cardiac myxoma is a rare condition, observed in about 3% of patients in sporadic cases, although it is more frequent in familial ones. Several mechanisms have been proposed to explain such recurrence, and the importance of increased vascularization as a facilitating feature is the subject of debate. The authors report the case of a non-familial right atrial myxoma, unusual for both its histopathology and recurrence.

[A case of native valve infective endocarditis in an immunocompromised patient]. / Um caso de endocardite infecciosa de válvula nativa em doente imunocomprometido.

Infective endocarditis continues to be associated with high mortality, despite the medical and surgical therapeutic options available. Surgical intervention is indicated in cases of heart failure or uncontrolled infection and sometimes for the prevention of embolic phenomena. The authors present the case of a 56-year-old male patient, with fibro-calcific mitral-aortic valve disease, splenectomized and with recently relapsed Hodgkin's lymphoma, who was admitted with infective endocarditis due to Streptococcus dysgalactiae. On the thirtieth day of directed antibiotic therapy, the mitral vegetation showed a significant increase in size and mobility. Surgery was considered at this point. However, given the patient's clinical stability and laboratory results, it was decided to adopt a conservative approach and to extend antibiotic therapy. The vegetation had regressed considerably seven days later. Given this atypical vegetation behavior, with slower than usual regression for the causative agent, the authors suggest that antibiotic therapy should be extended in patients with some degree of immunosuppression.

[Anomalous origin of left coronary artery: a malignant interarterial variant with a benign clinical course]. / Origem anómala da coronária esquerda: variante interarterial maligna com evolução clínica benigna.

Anomalous origin of coronary arteries represents a clinical challenge not only because of the anatomical variability, but also the possible functional consequences, pathophysiological mechanisms involved and the absence of large series in the literature that would provide evidence for clinical and therapeutic orientation. The authors describe the case of a 55-year-old male patient with a long history of atypical chest pain who was considered to have a low to intermediate likelihood of coronary artery disease. Therefore, and also bearing in mind his physical limitations (congenital left leg atrophy), he was referred for cardiac CT to rule out coronary artery disease. The exam showed a left coronary artery arising from the right coronary cusp and with an interarterial course, between the aorta and pulmonary trunk. Although this is a potentially malignant anatomical variant with surgical indication, a conservative approach was chosen, considering the late diagnosis and particular risk-benefit profile.

[Renal sympathetic denervation for treatment of resistant hypertension]. / Ablação da atividade simpática renal para tratamento da hipertensão arterial resistente.

Hypertension is an important cardiovascular risk factor and although there have been many improvements in pharmacological treatment, a significant percentage of patients are still considered resistant. The authors describe two cases of radiofrequency renal sympathetic denervation that illustrate the feasibility of this new technique for the treatment of resistant hypertension. The procedure consists of the application of radiofrequency energy inside the renal arteries to ablate afferent and efferent sympathetic renal activity, which has been implicated in the pathophysiology of hypertension.

Congenital long QT syndrome presenting as unexplained bradycardia.

Congenital long QT syndrome (LQTS) is a genetically autosomal heterogeneous disorder of the ion channels and causes about 10% of sudden death infant syndrome in newborns. Its estimated prevalence is approximately 1 in 2500, probably underestimated because of its clinical heterogenicity. Few cases of neonatal LQTS have been reported. In 4% of them, life-threatening arrhythmic events can be the first manifestation of LQTS. The authors report two cases of neonatal LQTS with heterogeneous genetic mutations. Both manifested by bradycardia, one since fetal life. One case had serious arrhythmias during beta blocker therapeutic establishment needing a pacemaker implantation. Genetic mutations found were not the most frequently described in association with neonatal bradycardia, thus the importance of this report. Presentation with bradycardia is relatively frequent in neonatal period, thus LQTS should be actively investigated in neonates with unexplained bradycardia. Beta blocker therapy reduces QTc and avoids arrhythmic events and sudden death.

Impact of common rhythm disturbances on echocardiographic measurements and interpretation.

Transthoracic echocardiography (TTE) remains the workhorse of noninvasive cardiac imaging, allowing to easily obtain precise information on cardiac structure and function. Over time, Doppler interrogation of blood flow velocities, direction, and timing in several locations within the heart became the primary method for haemodynamic assessment, replacing cardiac catheterization in most clinical settings and providing valuable diagnostic and prognostic information on a wide spectrum of cardiac pathological processes. Abnormalities in heart rate, rhythm, and intracardiac electrical conduction are commonly encountered during the performance of echocardiographic studies. Up to now, only a modest attention has been given to the impact of these abnormalities on the reading and interpretation of echocardiographic examination and this assessment has not yet been carried out in a global and systematic way. Tachyarrhythmias, bradyarrhythmias and atrioventricular conduction disturbances influence cardiac structure and mechanics as well as Doppler flow patterns. For this reason, and to be able to avoid misinterpretation, echocardiographers must be aware of the consequences of these common rhythm disturbances on echocardiographic findings. This narrative review aims to describe the current knowledge on this topic, focusing on the expected mechanical effects and Doppler patterns observed on transthoracic echocardiography in patients with common rhythm (tachycardia and bradycardia, atrial flutter and fibrillation and ectopic beats) and conduction disturbances (namely, atrioventricular block).

Relationship between rotors and complex fractionated electrograms in atrial fibrillation using a novel computational analysis.

INTRODUCTION: Rotors and complex fractionated atrial electrograms (CFAEs) have been suggested as possible therapeutic targets in ablation of atrial fibrillation (AF). The aim of this study was to assess the relationship between rotors and CFAEs in patients with AF. METHODS: We studied 18 patients with AF (mean age 69±8 years, 33% female) who underwent rotor ablation and pulmonary vein isolation. Endocardial mapping was performed with a basket catheter to identify the presence, number and location of rotors and CFAEs. The FIRM™ (Abbott) and CARTO™ (Biosense) systems were used with overlapping of frames from continuous 30-s recordings. CFAEs were classified as stable if present in >15 frames, moderately stable if present in 10-15 frames and unstable if present in 5-9 frames. RESULTS: A total of 44 rotors and 60 CFAEs (39 of them stable) were identified. The mean number of rotors and stable CFAEs per patient was 2.6±1.4 and 2.2±1.5, respectively. In 27 of the 44 identified rotors, CFAEs were found in the same location. Conversely, in 20 of the 39 stable CFAEs identified, a focal rotor was found in the same location. The majority of CFAEs found at the same location as a focal rotor were stable (63% vs. 37%, p=0.001). CONCLUSION: Rotors and CFAEs are frequently found in the same location within the atria, particularly when only stable CFAEs are considered. This relationship may have implications in the selection of substrate targets for ablation.

Impact of Renal Sympathetic Denervation on Left Ventricular Structure and Function at 1-Year Follow-Up.

BACKGROUND: Catheter-based sympathetic renal denervation (RDN) is a recent therapeutic option for patients with resistant hypertension. However, the impact of RDN in left ventricular (LV) mass and function is not completely established. Our aim was to evaluate the effects of RDN on LV structure and function (systolic and diastolic) in patients with resistant hypertension (HTN). METHODS AND RESULTS: From a single centre prospective registry including 65 consecutive patients with resistant HTN submitted to RDN between July-2011 and April-2015, 31 patients with baseline and 1-year follow-up echocardiogram were included in this analysis. Mean age was 65 ± 7 years, 48% were males, 71% had type 2 diabetes. Most had hypertension lasting for more than 10 years (90%), and were being treated with a median number of 6 anti-hypertensive drugs, including 74% on spironolactone. At 1-year, there was a significant decrease both on office SBP (176 ± 24 to 149 ± 13 mmHg, p<0.001) and DBP (90 ± 14 to 79 ± 11 mmHg, p<0.001), and also in 24h ABPM SBP (150 ± 20 to 132 ± 14 mmhg, p<0.001) and DBP (83 ± 10 to 74 ± 9 mmHg, p<0.001). There was also a significant decrease in LV mass from 152 ± 32 to 136 ± 34 g/m(2) (p<0.001), an increase in LV end diastolic volume (93 ± 18 to 111 ± 27 mL, p = 0.004), an increase in LV ejection fraction (65 ± 9 to 68 ± 9%, p = 0.001) and mitral valve E deceleration time (225 ± 49 to 247 ± 51 ms, p = 0.015) at 1-year follow up. There were no significant changes in left atrium volume index or in the distribution of patients among the different left ventricle geometric patterns and diastolic function subgroups. CONCLUSIONS: In this single centre registry of patients with resistant hypertension, renal denervation was associated with significant reduction in both office and ABPM blood pressure and a significant decrease in left ventricle mass evaluated by transthoracic echocardiogram at 1 year follow-up.

Pre-test probability of obstructive coronary stenosis in patients undergoing coronary CT angiography: Comparative performance of the modified diamond-Forrester algorithm versus methods incorporating cardiovascular risk factors.

BACKGROUND: Current guidelines recommend the use of the Modified Diamond-Forrester (MDF) method to assess the pre-test likelihood of obstructive coronary artery disease (CAD). We aimed to compare the performance of the MDF method with two contemporary algorithms derived from multicenter trials that additionally incorporate cardiovascular risk factors: the calculator-based 'CAD Consortium 2' method, and the integer-based CONFIRM score. METHODS: We assessed 1069 consecutive patients without known CAD undergoing coronary CT angiography (CCTA) for stable chest pain. Obstructive CAD was defined as the presence of coronary stenosis ≥50% on 64-slice dual-source CT. The three methods were assessed for calibration, discrimination, net reclassification, and changes in proposed downstream testing based upon calculated pre-test likelihoods. RESULTS: The observed prevalence of obstructive CAD was 13.8% (n=147). Overestimations of the likelihood of obstructive CAD were 140.1%, 9.8%, and 18.8%, respectively, for the MDF, CAD Consortium 2 and CONFIRM methods. The CAD Consortium 2 showed greater discriminative power than the MDF method, with a C-statistic of 0.73 vs. 0.70 (p<0.001), while the CONFIRM score did not (C-statistic 0.71, p=0.492). Reclassification of pre-test likelihood using the 'CAD Consortium 2' or CONFIRM scores resulted in a net reclassification improvement of 0.19 and 0.18, respectively, which would change the diagnostic strategy in approximately half of the patients. CONCLUSIONS: Newer risk factor-encompassing models allow for a more precise estimation of pre-test probabilities of obstructive CAD than the guideline-recommended MDF method. Adoption of these scores may improve disease prediction and change the diagnostic pathway in a significant proportion of patients.

Performance of traditional risk factors in identifying a higher than expected coronary atherosclerotic burden.

OBJECTIVE: To evaluate the performance of traditional cardiovascular (CV) risk factors in identifying a higher than expected coronary atherosclerotic burden. METHODS: We assessed 2069 patients undergoing coronary CT angiography, with assessment of calcium score (CS), for suspected coronary artery disease. A higher than expected atherosclerotic burden was defined as CS >75th percentile (CS >P75) according to age and gender-adjusted monograms. The ability of traditional CV risk factors to predict a CS >P75 was assessed in a customized logistic regression model ("Clinical Score") and by the calculation of SCORE (Systemic Coronary Risk Evaluation). The population attributable risk (PAR) of risk factors for CS >P75 was calculated. RESULTS: The median CS was 3.0 (IQR 0.0-98.0); 362 patients had CS >P75. The median SCORE was 3.0 (IQR 1.0-4.0). With the exception of hypertension, all traditional CV risk factors were independent predictors of CS >P75: diabetes, dyslipidemia, smoking and family history (OR 1.3-2.2, p≤0.026). The areas under the ROC curves for CS >P75 were 0.64 for the Clinical Score (95% CI 0.61-0.67, p<0.001) and 0.53 for SCORE (95% CI 0.50-0.56, p=0.088). About a quarter of patients with CS >P75 were in the two lower quartiles of the Clinical Score. Altogether, the traditional risk factors explain 56% of the prevalence of CS >P75 (adjusted PAR 0.56). CONCLUSION: Despite the association of CV risk factors with a higher than expected atherosclerotic burden, they appear to explain only half of its prevalence. Even when integrated in scores, the predictive power of these risk factors was modest, exposing the limitations of risk stratification based solely on demographic and clinical risk factors.

Predictors of Conversion from Radial Into Femoral Access in Cardiac Catheterization.

BACKGROUND: Fewer bleeding complications and early ambulation make radial access a privileged route for cardiac catheterization. However, transradial (TR) approach is not always successful, requiring its conversion into femoral access. OBJECTIVES: To evaluate the rate of conversion from radial into femoral access in cardiac catheterization and to identify its predictors. METHODS: Prospective dual-center registry, including 7632 consecutive patients undergoing catheterization via the radial access between Jan/2009 and Oct/2012. We evaluated the incidence of conversion into femoral access and its predictors by logistic regression analysis. RESULTS: The patients' mean age was 66 ± 11 years, and 32% were women. A total of 2969 procedures (38.4%) were percutaneous coronary interventions (PCI), and the most used first intention arterial access was the right radial artery (97.6%). Radial access failure rate was 5.8%. Independent predictors of conversion from radial into femoral access were the use of short introducer sheaths (OR 3.047, CI: 2.380-3.902; p < 0.001), PCI (OR 1.729, CI: 1.375-2.173; p < 0.001), female sex (OR 1.569, CI: 1.234-1.996; p < 0.001), multivessel disease (OR 1.457, CI: 1.167-1.819; p = 0.001), body surface area (BSA) ≤ 1.938 (OR 1.448, CI: 1.120-1.871; p = 0.005) and age > 66 years (OR 1.354, CI: 1.088-1.684; p = 0.007). CONCLUSION: Transradial approach for cardiac catheterization has a high success rate and the need for its conversion into femoral access in this cohort was low. Female sex, older age, smaller BSA, the use of short introducer sheaths, multivessel disease and PCI were independent predictors of conversion into femoral access.

Renal denervation in patients with resistant hypertension: six-month results.

INTRODUCTION: Increased activation of the sympathetic nervous system plays a central role in the pathophysiology of hypertension (HTN). Catheter-based renal denervation (RDN) was recently developed for the treatment of resistant HTN. AIM: To assess the safety and efficacy of RDN for blood pressure (BP) reduction at six months in patients with resistant HTN. METHODS: In this prospective registry of patients with essential resistant HTN who underwent RDN between July 2011 and May 2013, the efficacy of RDN was defined as ≥ 10 mm Hg reduction in office systolic blood pressure (SBP) six months after the intervention. RESULTS: In a resistant HTN outpatient clinic, 177 consecutive patients were evaluated, of whom 34 underwent RDN (age 62.7 ± 7.6 years; 50.0% male). There were no vascular complications, either at the access site or in the renal arteries. Of the 22 patients with complete six-month follow-up, the response rate was 81.8% (n=18). The mean office SBP reduction was 22 mm Hg (174 ± 23 vs. 152 ± 22 mm Hg; p<0.001) and 9 mm Hg in diastolic BP (89 ± 16 vs. 80 ± 11 mm Hg; p=0.006). The number of antihypertensive drugs (5.5 ± 1.0 vs. 4.6 ± 1.1; p=0.010) and pharmacological classes (5.4 ± 0.7 vs. 4.6 ± 1.1; p=0.009) also decreased significantly. Of the 24-hour ambulatory BP monitoring and echocardiographic parameters analyzed, there were significant reductions in diastolic load (45 ± 29 vs. 27 ± 26%; p=0.049) and in left ventricular mass index (174 ± 56 vs. 158 ± 60 g/m(2); p=0.014). CONCLUSION: In this cohort of patients with resistant HTN, RDN was safe and effective, with a significant BP reduction at six-month follow-up.

Coexistence of dynamic mitral regurgitation and dynamic left ventricular dyssynchrony in a patient with repeated episodes of acute pulmonary edema: improvement with cardiac resynchronization therapy.

A 69-year-old woman with idiopathic dilated cardiomyopathy and chronic heart failure experienced repeated hospital admissions for acute pulmonary edema with no recognizable precipitating factor. Worsening mitral regurgitation was triggered by exercise echocardiography and significant intraventricular dyssynchrony was elicited by low-dose dobutamine stress echocardiography. After cardiac resynchronization therapy she remained free of hospitalizations for 12 months. This case highlights the dynamic nature of both functional mitral regurgitation and left ventricular dyssynchrony and illustrates how in some patients stress echocardiography can help to clarify clinical scenarios and help with the challenging task of selecting patients who will benefit from cardiac resynchronization therapy.

A case of constrictive pericarditis and thoracic aortic aneurysm: a hybrid therapeutic approach.

The authors describe the case of a 59-year-old man, a former smoker, with hypertension, chronic renal failure undergoing hemodialysis, and a history of stent grafting for repair of an abdominal aortic aneurysm and miliary tuberculosis, who was diagnosed with constrictive pericarditis and a thoracic aortic aneurysm. In a patient with such a complex medical history, there were several etiologies to consider. The treatment consisted of pericardiectomy and a hybrid technique of supra-aortic debranching and subsequent endovascular stent-graft repair.

[Non-obstructive coronary artery disease documented by cardiac computed tomography: Discrepancy between atherosclerotic burden and cardiovascular risk]. / Doença coronária não obstrutiva documentada por tomografia computorizada cardíaca: contraste entre a carga aterosclerótica e o risco cardiovascular.

Cardiac computed tomography (CT) documents the presence of coronary artery disease, regardless of the degree of stenosis. The prognostic value of non-obstructive coronary artery disease documented by cardiac CT has recently been validated. However, there are still no clear guidelines on the management of such patients, particularly concerning initiation of more aggressive pharmacological measures for primary prevention. The approach to these patients remains controversial, especially in cases in which there is a discrepancy between cardiovascular risk and the atherosclerotic burden as documented by cardiac CT. The authors describe the case of a patient with a discrepancy between the extent of documented coronary atherosclerosis and that estimated according to pretest probability and cardiovascular risk scores. As this individual had more severe coronary atherosclerosis than expected (calcium score above the 90th percentile and non-obstructive coronary artery disease on cardiac CT) but was a competitive athlete and otherwise asymptomatic and without risk factors or cardiovascular history, with a very low estimated cardiovascular risk, it was difficult to decide on the risks and benefits of pharmacological primary prevention.