Early and late onset cardiotoxicity following anthracycline-based chemotherapy in breast cancer patients: Incidence and predictors.

INTRODUCTION: Cardiotoxicity represents a major limitation for the use of anthracyclines or trastuzumab in breast cancer patients. Data on longitudinal studies about early and late onset cardiotoxicity in this group of patients is scarce. The objective of the present study was to assess predictors of early and late onset cardiotoxicity in patients with breast cancer treated with A. METHODS: 100 consecutive patients receiving anthracycline-based chemotherapy (CHT) to treat breast cancer were included in this prospective study. All patients underwent evaluation at baseline, at the end of CHT, 3 months after the end of CHT and 1 and 4 years after the beginning of CHT. Clinical data, systolic and diastolic echo parameters and cardiac biomarkers including high sensitivity Troponin T (TnT), N-terminal pro-brain natriuretic peptide (NT-proBNP) and Heart-type fatty acid binding protein (H-FABP) were assessed. RESULTS: Mean doxorubicin dose was 243 mg/m2. Mean follow-up was 51.8 ± 8.2 months. At one-year incidence of anthracycline related-cardiotoxicity (AR-CT) was 4% and at the end of follow-up was 18% (15 patients asymptomatic left ventricular systolic dysfunction, 1 patients heart failure and 2 patients a sudden cardiac death). Forty-nine patients developed diastolic dysfunction (DD) during first year. In the univariate analysis DD during first year was the only parameter associated with AR-CT (Table 1). In the logistic regression model DD was independently related with the development of AR-CT, with an odds ratio value of 7.5 (95% CI 1.59-35.3). CONCLUSIONS: Incidence of late-onset cardiotoxicity is high but mostly subclinical. Diastolic dysfunction early after chemotherapy is a strong predictor of anthracycline cardiotoxicity.

Diastolic Dysfunction Following Anthracycline-Based Chemotherapy in Breast Cancer Patients: Incidence and Predictors.

INTRODUCTION: Cardiotoxicity represents a major limitation for the use of anthracyclines or trastuzumab in breast cancer patients. Data from longitudinal studies of diastolic dysfunction (DD) in this group of patients are scarce. The objective of the present study was to assess the incidence, evolution, and predictors of DD in patients with breast cancer treated with anthracyclines. METHODS: This analytical, observational cohort study comprised 100 consecutive patients receiving anthracycline-based chemotherapy (CHT) for breast cancer. All patients underwent clinical evaluation, echocardiogram, and measurement of cardiac biomarkers at baseline, end of anthracycline-based CHT, and at 3 months and 9 months after anthracycline-based CHT was completed. Fifteen patients receiving trastuzumab were followed with two additional visits at 6 and 12 months after the last dose of anthracycline-based CHT. A multivariate analysis was performed to find variables related to the development of DD. Fifteen of the 100 patients had baseline DD and were excluded from this analysis. RESULTS: At the end of follow-up (median: 12 months, interquartile range: 11.1-12.8), 49 patients (57.6%) developed DD. DD was persistent in 36 (73%) but reversible in the remaining 13 patients (27%). Four patients developed cardiotoxicity (three patients had left ventricular systolic dysfunction and one suffered a sudden cardiac death). None of the patients with normal diastolic function developed systolic dysfunction during follow-up. In the logistic regression model, body mass index (BMI) and age were independently related to the development of DD, with the following odds ratio values: BMI: 1.19 (95% confidence interval [CI]: 1.04-1.36), and age: 1.12 (95% CI: 1.03-1.19). Neither cardiac biomarkers nor remaining clinical variables were predictors of DD. CONCLUSION: Development of diastolic dysfunction after treatment with anthracycline or anthracycline- plus trastuzumab chemotherapy is common. BMI and age were independently associated with DD following anthracycline chemotherapy.

Cardiac anatomy for the interventional arrhythmologist: I.terminology and fluoroscopic projections.

Cardiac anatomy is complex and its understanding is essential for the interventional arrhythmologist. The first difficulty is the terminology used to describe the location of sites of mapping and ablation. For many years, electrophysiologists have named these positions following the conventional electrocardiographical vocabulary, or the terminology used by surgeons performing arrhythmic surgery. This traditional nomenclature, however, failed to take note of the crucial principle of considering the location of the heart in the human body as viewed in its erect position. In other words, it had failed to use an attitudinally appropriate terminology. Almost 10 years ago, a new attitudinal nomenclature was proposed for the right and left atrioventricular junctions. In this first of a series of reviews of cardiac anatomy as seen by the interventional arrhythmologist, we discuss the role of attitudinally appropriate terminology, and relate this to the projections used for cardiac fluoroscopy, fluorography, and angiography. Throughout our series of reviews, we will illustrate the value of The Visible Human Slice and Surface Server in facilitating the understanding of the fluoroscopic anatomy. (PACE 2010; 497-507).

Combined evaluation of bedside clinical variables and the electrocardiogram for the differential diagnosis of paroxysmal atrioventricular reciprocating tachycardias in patients without pre-excitation.

OBJECTIVES: The aim of this study was to assess the independent predictive contribution to the electrocardiogram (ECG) of bedside clinical variables to distinguish the major forms of paroxysmal supraventricular tachycardias. BACKGROUND: Atrioventricular nodal re-entrant tachycardias (AVNRTs) and orthodromic reciprocating tachycardias (ORTs), through concealed accessory pathways, are major mechanisms of paroxysmal atrioventricular re-entrant tachycardias. METHODS: We prospectively included 370 consecutive patients undergoing an electrophysiologic study for paroxysmal, regular, narrow-QRS complex tachycardias without pre-excitation in sinus rhythm. A diagnostic interpretation of ECG recordings was performed by 2 observers blinded to invasive diagnosis used as gold standard. The independent diagnostic contribution of basic clinical variables from a 7-item questionnaire was analyzed alone and in combination with the ECG interpretation by stepwise logistic regression. RESULTS: AVNRTs and ORTs were demonstrated in 262 and 108 patients, respectively. Age at symptom onset (odds ratio [OR]: 1.27), presence of palpitations in the neck (OR: 3.54), and female sex (OR: 2.96) (all p = 0.0001) were the clinical variables with significant diagnostic power for AVNRT diagnosis. These variables were selected by the logistic model as predictors of the tachycardia diagnosis when the ECG interpretation was included in the analysis (C statistic = 0.81 vs. 0.75 with clinical variables alone; p = 0.003). Neck palpitation was the only predictor of AVNRT when positive ECG findings were lacking. CONCLUSIONS: Age at the onset of symptoms, sensation of rapid regular pounding in the neck during tachycardia, and female sex are the only significant clinical variables in the differential diagnosis of paroxysmal atrioventricular reciprocating tachycardias in patients without pre-excitation in sinus rhythm. Their consideration adds significant diagnostic information to the ECG.

Independent predictive accuracy of classical electrocardiographic criteria in the diagnosis of paroxysmal atrioventricular reciprocating tachycardias in patients without pre-excitation.

AIMS: In patients without pre-excitation, the differential diagnosis of paroxysmal atrioventricular (AV) reciprocating tachycardias consists mainly of atrioventricular nodal re-entrant tachycardias (AVNRTs) and AV reciprocating tachycardias (AVRTs) through a concealed bypass. Our purpose was to validate the diagnostic accuracy of a predictive logistic model using classical electrocardiographic (ECG) criteria. METHODS AND RESULTS: We included 470 patients who underwent an electrophysiological study for paroxysmal, regular, and narrow-QRS complex tachycardia without pre-excitation in sinus rhythm. The ECG recordings were reviewed for the presence of the following: (i) pseudo r' deflection (V1) and/or pseudo s-wave (inferior leads), (ii) identifiable P-wave after the QRS complex, (iii) QRS alternans, and (iv) repolarization abnormalities during tachycardia. We performed a cross-validation method using the first 300 patients to develop a logistic model to predict the tachycardia diagnosis. The model was validated through the remaining 170 patients. The invasive study demonstrated AVNRT in 314 patients and AVRT in 156 patients. The presence of pseudo r' deflection and/or pseudo s-wave, a visible P-wave after the QRS complex, and QRS alternans were selected by a stepwise multiple logistic regression analysis as predictors for the diagnosis of AVNRT. The application of the model in the validation group showed a shrinkage prediction factor of 3%. Diagnostic probabilities for both tachycardia mechanisms depending on every combination of selected ECG criteria were >75% in 70% of the patients. CONCLUSION: The presence of pseudo r' deflection and/or pseudo s-wave, an identifiable P-wave after the QRS, and QRS alternans during tachycardia permit us to derive a reliable logistic model to predict the mechanism of paroxysmal AVRT in patients without pre-excitation. Precise probabilities for a correct diagnosis associated with every combination of those classical ECG criteria are presented.

Tachycardia-related channel in the scar tissue in patients with sustained monomorphic ventricular tachycardias: influence of the voltage scar definition.

BACKGROUND: Endocardial mapping before sustained monomorphic ventricular tachycardia (SMVT) induction may reduce mapping time during tachycardia and facilitate the ablation of unmappable VT. METHODS AND RESULTS: Left ventricular electroanatomic voltage maps obtained during right ventricular apex pacing in 26 patients with chronic myocardial infarction referred for VT ablation were analyzed to identify conducting channels (CCs) inside the scar tissue. A CC was defined by the presence of a corridor of consecutive electrograms differentiated by higher voltage amplitude than the surrounding area. The effect of different levels of voltage scar definition, from 0.5 to 0.1 mV, was analyzed. Twenty-three channels were identified in 20 patients. The majority of CCs were identified when the voltage scar definition was < or =0.2 mV. Electrograms with > or =2 components were recorded more frequently at the inner than at the entrance of CCs (100% versus 75%, P< or =0.01). The activation time of the latest component was longer at the inner than at the entrance of CCs (200+/-40 versus 164+/-53 ms, P< or =0.001). Pacing from these CCs gave rise to a long-stimulus QRS interval (110+/-49 ms). Radiofrequency lesion applied to CCs suppressed the inducibility in 88% of CC-related tachycardias. During a follow-up of 17+/-11 months, 23% of the patients experienced a VT recurrence. CONCLUSIONS: CCs represent areas of slow conduction that can be identified in 75% of patients with SMVT. A tiered decreasing-voltage definition of the scar is critical for CC identification.

[Non-fluoroscopic electroanatomical mapping (CARTO system) in the ablation of atrial tachycardias]. / La cartografía electroantómica no fluoroscópica (sistema CARTO) en la ablación de las taquicardias auriculares.

INTRODUCTION AND OBJECTIVES: The recent introduction of navigation systems has made substantial improvements in cardiac electrophysiological mapping. We present our experience with non-fluoroscopic electroanatomical mapping in patients with atrial tachycardias. PATIENTS AND METHOD: We studied 24 consecutive patients with atrial tachycardias (10 of whom had undergone previous radiofrequency ablation which failed). In all patients we performed electroanatomical mapping of the atria with the CARTO system, which combines electrophysiological and spatial information and allows visualization of atrial activation in a three-dimensional anatomical reconstruction of the atrial cavity. Mapping was performed during tachycardia (22 patients) or in sinus rhythm (2 patients), using a left atrial approach in 12 patients. Cooled-tip ablation was performed in 3 patients. RESULTS: Three-dimensional mapping distinguished clearly and rapidly between reentrant (9 patients) and focal mechanisms (15 patients). Radiofrequency catheter ablation was aimed at the critical isthmus of conduction (voltage maps) in patients with macroreentrant tachycardias. For focal tachycardias the catheter was re-navigated within the target area (activation maps) to the earliest focus of ectopic impulses. Acute success was obtained in 19 patients (79.2%), with early recurrence in 2 of them. Fluoroscopy time was 60 (21 min). CONCLUSIONS: Visualization of atrial activation in a three-dimensional reconstruction of the atria with the CARTO electroanatomical mapping system facilitated the integration of electrophysiological and anatomical information in patients with atrial tachycardias. This technique is potentially helpful in ensuring successful treatment of the substrate of tachycardia in this selected group of patients.

Ablation of electrograms with an isolated, delayed component as treatment of unmappable monomorphic ventricular tachycardias in patients with structural heart disease.

OBJECTIVES: We sought to evaluate the feasibility of identifying and ablating the substrate of unmappable ventricular tachycardia (VT). BACKGROUND: Noninducible and nonstable VT cannot be ablated by the conventional approach. METHODS: We studied 24 patients with documented monomorphic VT. Twenty-one patients had ischemic cardiomyopathy, two had nonischemic cardiomyopathy, and one had tetralogy of Fallot. Twelve patients had an implantable cardioverter-defibrillator. Conventional activation mapping was not possible in 18 patients: at least 1 of the clinical VTs or the clinical VT was not inducible in 12 patients, and VT was not tolerated in 6 patients. This group had experienced between 1 and 106 VT episodes in the month before the ablation procedure. Endocardial electroanatomic activation maps (Carto System) during sinus rhythm (SR) and right ventricular apex (RVA) pacing were obtained to define areas for which an electrogram displayed isolated, delayed components (E-IDC). These electrograms were characterized by double or multiple components separated by >/=50 ms. RESULTS: One area of E-IDC was recorded in 20 patients, and 2 or more were recorded in 4 patients. In 23 patients, these areas were detected during RVA pacing; in only 14 during SR. An E-IDC area related to the clinical VT was identified in each patient. Ablation guided by E-IDC suppressed all but one clinical VT whose inducibility suppression was tested. During a follow-up period of 9 +/- 4 months, three patients had recurrences of the ablated VT and two of a different VT. CONCLUSIONS: Electrograms with IDCs related to clinical VT can be identified in the majority of patients during RVA pacing. Radiofrequency ablation of E-IDC seems effective in controlling unmappable VT.

[Successful ablation of an automatic rhythm originating from his bundle]. / Ablación con éxito de un automático del haz de His.

Automatic junctional tachycardias are rare supraventricular tachyarrhythmias observed mainly in infants and children. This arrhythmia has a high mortality rate. We report the case of a 22-month-old infant in which the electrophysiological study disclosed an incessant junctional tachycardia originating from an automatic focus located in the His bundle region. Radiofrequency pulse delivery to the His bundle with controlled progressive heating of this region resulted in a definitive ablation of the ectopic focus without complications.