Diego Conde

New-onset atrial fibrillation after cavotricuspid isthmus ablation: identification of advanced interatrial block is key

AIMS A significant proportion of patients develop atrial fibrillation (AF) following cavotricuspid isthmus (CTI) ablation for typical atrial flutter (AFl). The objective of this study was to assess whether the presence of advanced interatrial block (aIAB) was associated with an elevated risk of AF after CTI ablation in patients with typical AFl and no prior history of AF. METHODS AND RESULTS This study included patients with typical AFl and no prior history of AF that were referred for CTI ablation. Patients were excluded when they had received repeat ablations or did not demonstrate a bidirectional block. In all patients, a post-ablation electrocardiogram (ECG) in sinus rhythm was evaluated for the presence of aIAB, defined as a P-wave duration ≥120 ms and biphasic morphology in the inferior leads. New-onset AF was identified from 12-lead ECGs, Holter monitoring, and device interrogations. The cohort comprised 187 patients (age 67 ± 10.7 years; ejection fraction 55.8 ± 11.2%). Advanced interatrial block was detected in 18.2% of patients, and left atrium was larger in patients with aIAB compared with those without aIAB (46.2 ± 5.9 vs. 43.1 ± 6.0 mm; P = 0.01). Over a median follow-up of 24.2 months, 67 patients (35.8%) developed new-onset AF. The incidence of new-onset AF was greater in patients with aIAB compared with those without aIAB (64.7 vs. 29.4%; P < 0.001). After a comprehensive multivariate analysis, aIAB emerged as the strongest predictor of new-onset AF [odds ratio (OR) 4.2, 95% confidence interval (CI): 1.9-9.3; P < 0.001]. CONCLUSION Advanced interatrial block is a key predictor for high risk of new-onset AF after a successful CTI ablation in patients with typical AFl.

Advanced Interatrial Block Predicts New Onset Atrial Fibrillation in Patients with Severe Heart Failure and Cardiac Resynchronization Therapy

Advanced interatrial block (aIAB) on the surface electrocardiogram (ECG), defined as a P‐wave duration ≥120 milliseconds with biphasic (±) morphology in inferior leads, is frequently associated with atrial fibrillation (AF). The aim of this study was to determine whether preoperative aIAB could predict new‐onset AF in patients with severe congestive heart failure (CHF) requiring cardiac resynchronization therapy (CRT).

Advanced interatrial block as a substrate of supraventricular tachyarrhythmias: a well recognized syndrome.

Interatrial blocks (IABs) are well described and accepted in the scientific community. In the last four decades major discoveries were made including its physiopathology, ECG presentation, classification and association with atrial tachyarrhythmias (advanced IAB). This article will briefly review the state of the art on the understanding of advanced IAB as an electrical substrate for atrial tachyarrhythmias as well as the future directions.

Bayés’ syndrome: the association between interatrial block and supraventricular arrhythmias

The past few years have given rise to extensive research on atrial conduction disorders and their clinical relevance. Most notably, an association between interatrial block and supraventricular arrhythmias has been discovered. This disorder, recently termed ‘Bayés’ syndrome’, has important clinical implications. In this article, the authors review normal atrial conduction and associated disorders. A particular focus is placed on Bayés’ syndrome and the relationship between interatrial block and supraventricular arrhythmias in different clinical scenarios. The report also outlines the current progress in the study of this syndrome and highlights areas requiring further investigation.

Relation of Interatrial Block to New-Onset Atrial Fibrillation in Patients With Chagas Cardiomyopathy and Implantable Cardioverter-Defibrillators

Chagas cardiomyopathy is an endemic disease in Latin America. A significant proportion of patients develop atrial fibrillation (AF), which may result in stroke and increased morbidity or mortality. Interatrial block (IAB) has been associated with the development of AF in different clinical scenarios. The aim of our study was to determine whether IAB can predict new-onset AF in patients with Chagas cardiomyopathy and implantable cardioverter-defibrillators (ICDs). We conducted a retrospective study of patients with Chagas cardiomyopathy and ICDs from 14 centers in Latin America. Demographics, clinical, and device follow-up were collected. Surface electrocardiograms were scanned at 300 dpi and maximized ×8. Semiautomatic calipers were used to determine P-wave onset and offset. Partial IAB was defined as a P wave of >120 ms and advanced IAB as a P wave of >120 ms with biphasic morphology (±) in inferior leads. AF events and ICD therapies were reviewed during follow-up by 2 independent investigators. A total of 80 patients were analyzed. Mean age was 54.6 ± 10.4 years, and 52 (65%) were male. Mean left ventricular ejection fraction was 40 ± 12%. IAB was detected in 15 patients (18.8%), with 8 (10.0%) partial and 7 (8.8%) advanced. During a follow-up of 33 ± 20 months, 11 patients (13.8%) presented with new AF. IAB (partial + advanced) was strongly associated with new AF (p <0.0001) and inappropriate therapy by the ICD (p = 0.014). In conclusion, IAB (partial + advanced) predicted new-onset AF in patients with Chagas cardiomyopathy and ICDs.

A laboratory study on the reliability estimations of the mini-CEX

Reliability estimations of workplace-based assessments with the mini-CEX are typically based on real-life data. Estimations are based on the assumption of local independence: the object of the measurement should not be influenced by the measurement itself and samples should be completely independent. This is difficult to achieve. Furthermore, the variance caused by the case/patient or by assessor is completely confounded. We have no idea how much each of these factors contribute to the noise in the measurement. The aim of this study was to use a controlled setup that overcomes these difficulties and to estimate the reproducibility of the mini-CEX. Three encounters were videotaped from 21 residents. The patients were the same for all residents. Each encounter was assessed by 3 assessors who assessed all encounters for all residents. This delivered a fully crossed (all random) two-facet generalizability design. A quarter of the total variance was associated with universe score variance (28%). The largest source of variance was the general error term (34%) followed by the main effect of assessors (18%). Generalizability coefficients indicated that an approximate sample of 9 encounters was needed assuming a single different assessor per encounter and assuming different cases per encounter (the usual situation in real practice), 4 encounters when 2 raters were used and 3 encounters when 3 raters are used. Unexplained general error and the leniency/stringency of assessors are the major causes for unreliability in mini-CEX. To optimize reliability rater training might have an effect.

Progressive Interatrial Block and Supraventricular Arrhythmias

Interatrial conduction disorders are frequent in patients with structural heart diseases, including hypertension, coronary disease, and hypertrophic cardiomyopathy, and they are strongly associated with atrial tachyarrhythmias, especially atrial fibrillation and flutter. Conduction delays lead to dispersion of refractory periods and participate in initiating and maintaining reentry circuits, facilitating atrial arrhythmias. In this case, the changing pattern over time is a manifestation of progressive atrial remodeling and conduction delay. The terminal negative component of the P wave in the inferior leads suggests block of the electrical impulse in the Bachman bundle zone, with retrograde activation of the left atria via muscular connections at the coronary sinus. This has been reproduced in experimental models and confirmed by endocardial mapping. Physicians should be aware of the association between advanced interatrial block and development of atrial arrhythmias as its recognition could prompt early and aggressive antiarrhythmic treatment.

Vernakalant versus electrical cardioversion in recent-onset atrial fibrillation

Introduction: Vernakalant is a new, safe and effective drug used intravenously for conversionAFand studied inpatientswith andwithout structural heart disease; even after cardiovascular surgery [1–4]. Vernakalant has proved to be more rapid in converting recent onset AF to sinus rhythm compared to placebo, amiodarone, propafenone and flecainide [5–7]. Up to the present no study has been conducted comparing vernakalantwith electrical cardioversion (EC) for conversion of recent-onset atrial fibrillation. The goal of our study was to compare the conversion rate of recentonset AF, hospital stay length and adverse events in hemodynamically stable patients without structural heart disease treated with intravenous vernakalant or EC. Methods: This is an observational study which includes 60 patients from July 1, 2011 to October 30, 2012, hemodynamically stable with symptomatic recent onset AF (lasting less than 48 h)without structural heart disease. EC was performed in 30 patients and other 30 patients received an initial intravenous dose of vernakalant, 3.0 mg/kg over 10 min, followed by a 15 min observation period and, if conversion to sinus rhythmdid not occur, a second 10 min infusion of vernakalant at a dose of 2 mg/kg was administered. The EC protocol started with 100 J, if patients persisted with AF the protocol continued with 200 J and then with 360 J if have been necessary. All EC were performed under sedation with intravenous propofol and with a fasting for a minimum of 3 h. If patients persisted with AF after pharmacological cardioversion, the EC was done at 2 h after intravenous vernakalant with the same protocol. Inclusion criteria: Patients N 18 years, with AF lasting less than 48 h and documented by electrocardiogram, weights between 45 and 136 kg, systolic blood pressure N 90 mmHg and b160 mmHg and diastolic blood pressure b 95 mmHg. Exclusion criteria: Pregnancy, atrial flutter, sinus node disease, QRS duration longer than 140 ms in non-paced beats, QT interval N 440 ms, heart failure or acute coronary syndrome. Clinical, laboratory and electrocardiographic variables were recorded. All the patients had continuous electrocardiographic monitoring. Color Doppler echocardiographies with measurement of structural and functional parameters were performed to all the patients. Primary outcomemeasure: the conversion rate, hospital stay length and adverse events in both groups. Adverse events: death, sustained hypotension (systolic blood pressure ≤ 90 mm Hg), bradycardia b 40 beats per minute, QT interval N 440 ms, ventricular arrhythmia (≥triplets), or any other event that required or prolonged hospitalization were considered adverse events. Other events not meeting the criteria of seriousness, taste disorders, cough, nausea or dizziness were not considered serious adverse events. The patients will receive anticoagulation therapy after discharge according the recommendation of CHA2DS2-VASc score, but without antiarrhythmics drugs. Statistical analysis: All calculations were performed using Statistix 8.0 software package. Continuous variables were expressed as median with the corresponding interquartile range (p25–p75) and were compared using the Mann–Whitney test. Rates were expressed as percentages and were compared using the chi square test with Fishers correction, if applicable. This investigationwas inaccordancewith theDeclaration ofHelsinki. Results: Sixty patients were included; median age was 65 years and 70% were men. No significant differences were found between the baseline characteristics and previous events of atrial fibrillation, invasive procedures and medication in the two groups. Conversion rate was 91% in the vernakalant group at 2 h and 100% in EC group (p= NS). Hospital stay length was 246 min (IQR, 190–280) in the vernakalant group versus 263 min (IQR, 120–276) in the EC group (P= NS). No adverse events were reported. Discussion: Vernakalant is a novel, relatively atrial-selective antiarrhythmic agent that is used intravenously, which prolongs the atrial refractory period but has little effect on ventricular repolarization. It is a multi-ion channel blocker blocking early-activating potassium channels combined with concentration-, voltageand frequency-dependent blockade of sodium channels [1–4]. There are two studies which showed that vernakalant is faster for conversion of recent-onset AF than placebo, amiodarone, propafenone and flecainide [5–7]. There is another study which showed that the change of perception of state of health between screening and 2 h after receiving the drugswas 4431 Letters to the Editor

High-sensitive troponin T levels and complex coronary lesions

window with well-known adverse effects, some of which may themselves be life-threatening. These include ventricular arrhythmias, angina, myocardial infarction, pulmonary edema, sudden sharp increase in blood pressure, and intracranial hemorrhage [8]. Milder adverse effects include anxiety, fear, restlessness, headache, dizziness, palpitations, pallor, and tremor. Patients at higher risk for serious adverse effects from epinephrine are those with comorbidities such as underlying heart disease and those taking monoamine oxidase inhibitors, tricyclic antidepressants, antiarrhythmics, and cocaine [8]. Errors associated with epinephrine administration relate to dosing (related to concentration and ratio dose expressions, ie, 1:1000 and 1:10 000), name (mistaken with ephedrine), and route [8,9]. Furthermore, based on the recommended dosing for children (0.01 mg/kg of 1:1000 solution) and that only 2 fixed doses of epinephrine are available by autoinjector (0.15 and 0.3 mg), children weighing less than 15 kg are overdosed with the 0.15-mg autoinjector, whereas children weighing between 15 and 30 kg are underdosed if treated with 0.15 mg, yet overdosed if treated with 0.3 mg [8]. Despite the potential for adverse effects, medication interactions, and administration errors, epinephrine still remains the first-line treatment for anaphylaxis [2]. For the potentially fatal cases of anaphylaxis refractory to epinephrine, alternative therapies are essential. We feel that the benefits, highlighted in our report [1], compared with the risks, summarized in both our report and this correspondence, favor the use of methylene blue in cases of anaphylaxis refractory to conventional treatment.

B-type natriuretic peptide predicts complexity and severity of the coronary lesions in patients with acute coronary syndromes

this view. Through paresternal LV long(Fig. 2A) and short-axis views (Figs. 1B and 2B), the hypotrophy pattern of the myocardium can be clearlyvisualizedandquantified(Figs.2 and3);also, valvepathologycan also be ruled out by using both 2-dimensional/color Doppler image. Apical 5-/4-chamber view is recommended during diagnosis of HCM complications such as dynamic LVOT obstruction, mitral valve SAM condition, as well as MR (Fig. 3). Doppler ultrasonography of LVOT flow in this view could also largely facilitate the measurement of pressure gradient during systolic phase (mean pressure gradient≥30 mm Hg at rest) (Fig. 3C). This view can also help to rule out the LV hypotrophy caused by aortic stenosis (Fig. 4A). Different from LVOT obstruction in HCM, the blood flow acceleration point should be located in the aortic valve level rather than the LV flow tract (Fig. 4B-C).