Luz Maria Rodriguez

Improvement in left ventricular function by ablation of atrioventricular nodal conduction in selected patients with lone atrial fibrillation

Left ventricular (LV) function was studied in 30 patients with lone atrial fibrillation (AF) (paroxysmal [n = 27] and persistent [n = 3]) before and after ablation of atrioventricular conduction. In all patients, drug treatment did not control ventricular rate during AF or prevent recurrences of the arrhythmia, or both. LV ejection fraction, and LV end-systolic and end-diastolic, and left atrial dimensions were measured by echocardiography before (mean 7 +/- 10 months, range < 1 to 37) and after (14 +/- 20 months, < 1 to 77) ablation. Before ablation, LV ejection fraction was < or = 50% in 12 patients (group I) and > 50% in 18 (group II). After ablation, LV ejection fraction increased significantly in group I from 43 +/- 8% to 54 +/- 7% (p < 0.0001). There were also significant decreases in LV-end systolic and end-diastolic, and left atrial dimensions. No changes in these parameters were observed in group II. Groups I and II had a significant difference in the duration of AF (group I: mean 11 years, range 8 to 28; and group II: 5 years, 2 to 14) (p < 0.05). No difference was present in age, sex, New York Heart Association functional class for dyspnea, or type of ablation procedure. Thus, some patients with lone AF may show deterioration of LV function, which appears to be related to the duration of the arrhythmia; in these cases, LV function may improve significantly after ventricular rate control is accomplished by ablation of atrioventricular conduction.

Desmoglein-2 and Desmocollin-2 Mutations in Dutch Arrhythmogenic Right Ventricular Dysplasia/Cardiomypathy Patients Results From a Multicenter Study

Background— This study aimed to evaluate the prevalence and type of mutations in the major desmosomal genes, Plakophilin-2 (PKP2), Desmoglein-2 (DSG2), and Desmocollin-2 (DSC2), in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) patients. We also aimed to distinguish relevant clinical and ECG parameters. Methods and Results— Clinical evaluation was performed according to the Task Force Criteria (TFC). We analyzed the genes in (a) 57 patients who fulfilled the ARVD/C TFC (TFC+), (b) 28 patients with probable ARVD/C (1 major and 1 minor, or 3 minor criteria), and (c) 31 patients with 2 minor or 1 major criteria. In the TFC+ ARVD/C group, 23 patients (40%) had PKP2 mutations, 4 (7%) had DSG2 mutations, and 1 patient (2%) carried a mutation in DSC2, whereas 1 patient (2%) had a mutation in both DSG2 and DSC2. Among the DSG2 and DSC2 mutation-positive TFC+ ARVD/C probands, 2 carried compound heterozygous mutations and 1 had digenic mutations. In probable ARVD/C patients and those with 2 minor or 1 major criteria for ARVD/C, mutations were less frequent and they were all heterozygous. Negative T waves in the precordial leads were observed more (P<0.002) among mutation carriers than noncarriers and in particular in PKP2 mutation carriers. Conclusions— Mutations in DSG2 and DSC2 are together less prevalent (10%) than PKP2 mutations (40%) in Dutch TFC+ ARVD/C patients. Interestingly, biallelic or digenic DSC2 and/or DSG2 mutations are frequently identified in TFC+ ARVD/C patients, suggesting that a single mutation is less likely to cause a full-blown ARVD/C phenotype. Negative T waves on ECG were prevalent among mutation carriers (P<0.002).

Clinical and electrophysiologic characteristics of exercise-related idiopathic ventricular tachycardia

In 37 (70%) of 53 patients with idiopathic ventricular tachycardia (VT), episodes were mainly related to exercise (group 1). These patients were younger (33 +/- 14 vs 44 +/- 18 years, p = 0.015) and more often had dizziness during VT (71 vs 40%, p = 0.003) than the 16 patients in whom VT was not exercise-related (group 2). Patients in group 1 needed cardioversion less often to terminate the arrhythmia (4 (11%) vs 6 (40%), group 2 [p = 0.04]). VT was initiated during exercise testing in 62% of patients in group 1 but in only 1 patient in group 2 (p = 0.0004). Induction of clinical VT during programmed stimulation was observed in a similar percentage in group 1 (49%) and group 2 (50%) patients. Isoproterenol infusion facilitated the induction of VT in 9 of 20 (45%) group 1 and in 2 of 8 (25%) group 2 patients (p = not significant). After a mean follow-up of 2.9 +/- 2.5 years, 8 (22%) group 1 patients and 5 (31%) group 2 had at least 1 episode of symptomatic VT. Only 1 patient died suddenly. Class III drugs were the most useful in preventing recurrences. Beta-blocking agents were of little value in both groups. Patients with VT and a structurally normal heart have a good prognosis despite recurrences of their arrhythmia. The relation of the arrhythmia to exercise has no prognostic implications.

Time Course and prognostic significance of serial signal-averaged electrocardiograms after a first acute myocardial infarction

The prognostic significance of serial signal-averaged electrocardiograms recorded during the first 3 days (period 1), in the second week (period 2) after a first acute myocardial infarction (AMI) and 6 months later (period 3) was prospectively assessed in 190 patients. No patients were treated with thrombolytic therapy. Patients with conduction disturbances were excluded. Mean age of the 190 patients was 57 years (range 34 to 74) and mean left ventricular ejection fraction was 40 + 6% (range 12 to 70). Eighty-four patients had an anterior wall AMI and the remaining 106 patients an inferior wall AMI. After a mean follow-up of 24 months, 16 patients developed sustained symptomatic monomorphic ventricular tachycardia, 7 patients were resuscitated from an episode of ventricular fibrillation, and 10 patients died suddenly. Multivariate regression analysis using continuous variables showed that the strongest predictor of sustained ventricular tachycardia and ventricular fibrillation was the left ventricular ejection fraction (p less than 0.0001) followed by the duration of QRS complex on the signal-averaged electrocardiogram recorded during the first 3 days of AMI (p less than 0.0005). Sudden death was only predicted by left ventricular ejection fraction (p less than 0.02).

The Asymptomatic Patient with the Wolff‐Parkinson‐White Electrocardiogram

Sudden death can be the first manifestation of the Wolff‐Parkinson‐White (WPW) syndrome. The underlying mechanism being atrial fibrillation with a very high ventricular rate, because of a short anterograde refractory period of the accessory atrioventricular pathway (AP), deteriorating into ventricular fibrillation. Information on the anterograde refractory period of the AP is therefore important to recognize asymptomatic people with the WPW ECG at risk for dying suddenly. Several noninvasive tests are available to identify the low risk patient. Decision making when to interrupt the AP in asymptomatic WPW patients not at low risk requires an invasive study to document the electrophysiological properties of the AP and to determine its exact location.

Radiofrequency Ablation of a Focal Atrial Tachycardia Originating From the Marshall Ligament as a Trigger for Atrial Fibrillation

A 66-year-old woman with a history of typical atrial flutter and atrial fibrillation was referred to our institution for radiofrequency ablation. In 1997, her atrial flutter was successfully ablated. During the next 4 years, she remained free of both arrhythmias. In 2001, the patient presented again with atrial fibrillation. During the subsequent electrophysiological study, the index arrhythmia was an incessant atrial tachycardia (AT), 170 bpm (Figure 1, left). A 3-dimensional electroanatomic map (CARTO; Biosense Webster, Inc) of the right atrium (RA) during tachycardia clearly demonstrated a tachycardia originating in the left atrium (LA) (Figure 2). Mapping of the LA …

Clinical characteristics and electrophysiologic properties of atrioventricular accessory pathways : importance of the accessory pathway location

OBJECTIVES This study was designed to assess the influence of accessory atrioventricular (AV) pathway location on the clinical and electrophysiologic characteristics of 384 consecutive symptomatic patients having a single accessory pathway. METHODS Four locations were studied: left free wall (n = 270), posteroseptal (n = 52), anteroseptal (n = 29) and right free wall (n = 33). Ten clinical variables and 12 electrophysiologic variables were analyzed, including the effective refractory period of the accessory pathway and the different clinically occurring and inducible arrhythmias. RESULTS Only two clinical findings were associated with accessory pathway location: 1) later age at onset of symptoms in the left free wall versus other accessory pathway locations (24 +/- 12 vs. 20 +/- 11 years, p = 0.02), and 2) later age at the time of electrophysiologic study in the left free wall accessory pathway location (36 +/- 13 vs. 32 +/- 11 years, p = 0.01). Six electrophysiologic variables showed a correlation with the accessory pathway location: 1) retrograde conduction only was found less frequently in right free wall (9%) and anteroseptal (10%) than in left free wall (26%) and posteroseptal (29%) accessory pathway locations (p = 0.05); 2) the retrograde effective refractory period of the accessory pathway was shorter in anteroseptal (253 +/- 52 ms) and left free wall (270 +/- 72 ms) as compared with right free wall (296 +/- 101 ms) and posteroseptal (301 +/- 76 ms) locations (p = 0.05); 3) retrograde decremental conduction over the accessory pathway was present in the posteroseptal (17%) and left free wall (3%) but absent in the other locations (p less than 0.001); 4) anterograde decremental conduction was only seen in the right free wall location (12%) (p less than 0.001); 5) orthodromic reentrant tachycardia was induced less frequently in the right free wall than in other locations (70% vs. 93%, p less than 0.001); and 6) inducibility of atrial fibrillation was greater in anteroseptal (62%) than in right free wall (21%), left free wall (44%) and posteroseptal (36%) locations (p = 0.01). CONCLUSIONS The location of the accessory AV pathway is associated with specific electrophysiologic characteristics.

Use of a saline-irrigated tip catheter for ablation of ventricular tachycardia resistant to conventional radiofrequency ablation : Early experience

Irrigated Tip Catheter for Ablation of Resistant VT. Introduction: Radiofrequency (RF) catheter ablation of ventricular tachycardia (VT) may fail if the critical isthmus is located intramyocardially or epicardially. The design of a saline‐irrigated tip (SIT) catheter (Thermo‐Cool™, Cordis‐Webster) involves active cooling of the tip electrode, which allows creation of larger ablation lesions.

Arrhythmia Risk: Eiectrophysiological Studies and Monophasic Action Potentials

Shortly after in the introduction of progrommed electrical stimulotion (PES) of the heart to study and localize cardiac arrhythmias in the intact human heart, the technique was used for risk stratification of the arrhythmia patient. Two decades later we have to conclude that especially in ventricular arrhythmias the technique of PES did not live up to our expectations and the left ventricular function is a better long‐term predictor than the induction of ventricular arrhythmias or the ability to find an antiarrhythmic drug able to prevent the initiation of the classically documented ventricular arrhythmia. Another sobering finding come from the analysis of the characteristics of the patient dying suddenly out‐of‐hospital, which showed that most of those patients could not be classified before the event as being at high risk using noninvasive or invasive testing, not even in those with o previous cardiac history. Monomorphic action potential (MAP) recordings have been of importance in our understanding of torsade de pointe arrhythmias in congenital and acquired QT prolongation. A major problem in case of a less generalized electrophysiological abnormality is the identification of the appropriate place where to put the MAP‐electrode.

The atrioventricular interval during pre-excited tachycardia: A simple way to distinguish between decrementally or rapidly conducting accessory pathways

BACKGROUND Recognition of the presence and role of decremental fibers during wide QRS tachycardia requires carefully executed intracardiac studies. OBJECTIVE This study sought to determine the value of the atrioventricular (AV) conduction time during pre-excited tachycardia to differentiate a fast from a decrementally conducting accessory pathway (AP). METHODS Fifty-one patients with 56 pre-excited tachycardias were included in the study: Group I: 27 patients with 31 antidromic tachycardia (ADT) using an atriofascicular pathway, Group II: 2 patients with pre-excited tachycardia due to bystander AV conduction, Group III: 3 patients with ADT and a short AV Mahaim fiber, and Group IV: 19 patients with 21 ADT using a fast conducting right-sided AP. The AV interval was measured in the His bundle electrogram and related to the tachycardia cycle length (TCL) by making an AV/TCL index. RESULTS An AV interval > or = 150 ms during pre-excited tachycardia yielded a 91% sensitivity, 90% specificity, positive predictive value of 94%, and negative predictive value of 83% for AV conduction over a decrementally conducting pathway, whereas a > or =0.55 AV/TCL index yielded a sensitivity of 89%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 84%. In 3 of 4 patients with Mahaim fibers and a <0.55 AV/TCL index, a prolonged ventriculoatrial (VA) conduction time was found. CONCLUSIONS An AV interval > or =150 ms during pre-excited tachycardia is a fast and reliable method for detecting a decrementally conducting AP. Correcting the AV interval by the tachycardia cycle length improved specificity and positive predictive accuracy.