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Notes: This report describes the termination of persistent AF refractory to multiple cardioversions and antiarrhythmic therapy in a patient without structural heart disease, with a single radiofrequency application delivered in the left upper pulmonary vein. The observations and failure of repeated internal and external cardioversion suggest a rapidly firing arrhythmia focus sustaining atrial fibrillation amenable to curative pulmonary vein ablation. (PACE 2003; 26:1420–1423)

Notes: Depression and reduced sexual functioning have been identified as problems following ICD placement. We examined these issues, and multiple other quality-of-life measures, and their relationship to ICD and ICD discharge. Patients were 64 ± 11 years old, 72% male, and had undergone ICD 20 ± 14 months previously. Fifty-eight patients responded to a confidential biopsychosocial questionnaire. Positive attitudes toward the procedure increased from 52% before to 76% after implantation. Satisfaction correlated most strongly with less anger (P = 0.002, r = 0.45), less worry about ICD size (P = 0.007, r = 0.38), less sadness (P = 0.01, r = 0.37), and perceived better health (P = 0.01, r = 0.35). Of these ICD patients, 20%–58% reported measures of depression, and sexual frequency was reduced in 45%. Despite successful ICD placement, health concern increased in 62 % of the respondents. Thirty-nine percent attended support groups; 96% found them very helpful. Mean number of ICD discharges described by responders was 5 ± 11. Fifty percent of our sample reported ≥ 1 shock; equal numbers had 1, 2–5, 6–10, and more than 10 shocks. Sixty-two percent of men had at least one discharge compared to 13% of women. After controlling for cardiac clinical variables, experiencing ≥ 1 ICD shock was strongly associated with anxiety about family (odds ratio = 7.3), reduced new activities (odds ratio = 6.9), increased sadness (odds ratio = 6.2), and health worry (odds ratio = 5.8). Experiencing ≥ 5 ICD shocks was strongly associated with increased health concern (odds ratio = 13.6), increased sadness (odds ratio = 12.5), increased fatigue (odds ratio = 6.1), current sadness (odds ratio = 5.8), and increased nervousness (odds ratio = 5.3). ICD implantation powerfully affects quality-of-life. Postimplantation health concern is paradoxically increased despite improvement in actual health. Negative emotions are associated with defibrillator discharge.

Notes: General modalities of analyses that have, been used for ICD studies are reviewed. Published “typical” examples are briefly described. The historical cohort method is exemplified with previously unpublished data from the Seattle Cardiac Arrest Survivor database. The AVID Study database is used to compare the results obtained from nonrandomized methodologies with randomized methodologies. Particular issues related to the use of the ICD for example, mode of death, inability to blind, selection practice, and treatment decision times make this a natural pedagogic platform.

Notes: While abnormalities in the P wave SAECG have been associated with the occurrence of AF, its reproducibility has never been documented. The purpose of this study was to evaluate the immediate and short-term reproducibility of measurements from the P wave SAECG. P wave SAECGs were obtained using well-described techniques that utilize the QHS complex as the trigger and the P wave as template for averaging. In 28 subjects (8 controls, 11 with cardiac disease, 9 with prior AF), 3 P wave SAECGs were obtained: an initial study; an immediate reacquisition; and reacquisition after 4–5 days. Vector duration and RMS voltage of the terminal 20 ms of the P wave SAECG were measured and compared. The mean P wave duration was 152 ± 14 ms on initial SAECG, 152 ± 14 ms and 152 ± 15 ms at immediate and short-term reacquisitions, respectively (both P = NS vs initial). The mean terminal BMS voltage was 6.4 ± 6.0 mcV on initial SAECG, 6.4 ± 5.9 mcV and 6.5 ± 5.8 meV at immediate and short-term reacquisitions, respectively (both P = NS vs initial). Linear regression analysis showed high reproducibility for both P wave duration (r = 0.94 for immediate and r = 0.96 for short-term reacquisition vs initial) but slightly less for terminal RMS voltage (r = 0.92 for immediate and r = 0.84 for short-term reacquisition vs initial). In subgroup analysis, P wave duration measurements were highly reproducible in controls, in subjects with cardiac disease, and in those with a history of AF. P wave duration was also reproducible for both males and females, as well as for subjects age 〉 65 years (r = 0.96 and 0.89 for immediate and short-term reacquisition, respectively). Terminal RMS voltage measurements were reproducible for controls, but less reproducible in other subgroups. In conclusion, P wave duration measurements on SAEGG are reproducible when evaluated at immediate and short-term reacquisition regardless of age, sex, cardiac disease, or prior AF. Terminal RMS voltages were less reproducible, especially in patients with cardiac disease and/or prior AF. These findings may explain conflicting observations regarding the clinical utility of terminal P wave measurements.

Notes: Update on SAECG. The signal-averaged electrocardiogram (SAECG) facilitates noninvasive recording of low-amplitude cardiac signals such as ventricular late potentials. The SAECG has been used to accurately predict life-threatening ventricular tachyarrhythmias in patients after acute myocardial infarction and with nonischemic dilated cardiomyopathy, and to screen for inducible ventricular tachycardia in patients with unexplained syncope and with nonsustained ventricular tachycardia. This review focuses on currently accepted methodology and clinical and research applications of the SAECG.

Notes: Ablation and Coagulation Activation. Introduction: Although thromboembolism is an uncommon complication of radiofrequency (RF) ablation, some preliminary reports have suggested that RF ablation results in activation of the coagulation system, possibly increasing this risk. We hypothesized that the insertion of intravenous catheters and their prolonged intravenous placement rather than RF ablation activates the coagulation cascade. Methods and Results: Thirty-seven patients, group 1 (n = 21) during RF ablation, and group 2 (n = 16) during routine electrophysiologic studies (EPS), were studied prospectively. Blood was drawn for coagulation and fibrinolytic studies following insertion of venous sheaths (TO), following catheter placement (T1), and 1 hour after completion of RF ablation or EPS {T2). Conversion of prothrombin to thrombin was measured using thrombin-antithrombin complex (TAT) and prothrombin activation peptide (F1+2). and fibrinolytic activity was assessed using D-dlmer concentration. Levels of D-dimer increased in group 1 from 823.52 ± 323.52 ng/mL at TO to 1,314.28 ± 297.63 ng/mL at T2 (P= 0.005), and in group 2 from 658.15 ± 161.70 ng/mL at T0 to 1625 641.45 ng/mL at T2 (P=±0.064). TAT levels increased from to 27.74 ± 5.6 μg/L at T0 to 52.99 ± 5.93 μg/L at T2 in group 1 (P= 0.09), and from 19.79 ± 5.14 μg/L at T0 to 73.5 ± 24.15 μg/L at T2 in group 2 (P= 0.05). F1+2 concentration increased from 1.52 ± 0.30 nmol/L at T0 to 3.06 ± 0.41 nmol/L at T2 in group 1 (P= 0.004), and from 1.32 ± 0.30 nmol/L at T0 to 3.11 ± 0.46 nmol/L at T2 in group 2 (P= 0.087). There was no significant difference in the concentration of the three coagulation variables between group 1 and group 2 at any given time point. No correlation was demonstrable between concentration of D-dimers, TAT, or F1+2 and variables of RF delivery such as cumulative energy, number of RF energy applications, or number of impedance rises. However, a significant positive correlation (r = 0.65, P 〈 0.01) was noted between the duration of the RF ablation procedure and the concentration of D-dimers. Conclusion: We conclude that activation of the coagulation cascade in RF ablation procedures is not related to the delivery of RF energy, but is related to the placement of intravascular catheters and to the duration of the ablation procedure.

Notes: Background: The signal-averaged electrocardiogram (SAECG) is a useful noninvasive diagnostic tool for assessing delayed ventricular activation.Methods: The advantage of the SAECG over standard ECGs the ability to detect very low amplitude signals indicative of areas of slowed myocardial conduction, a requirement for reentrant arrhythmias.Results: The SAECG has been proven useful in a variety of clinical situations, particularly in risk stratification after myocardial infarction or in the patient with dilated cardiomyopathy, and in screening for the need for electrophysiological studies in the syncope patient or the patient with nonsustained ventricular tachycardia.Conclusions: This review focuses on the currently accepted methodology of the time-domain SAECG, and outlines the standard applications of the SAECG based on the results of important clinical research.

Notes: Background: Patients with prolonged signal-averaged ECG have four times higher risk for development of atrial fibrillation (AF) after coronary artery bypass surgery (CABG). Incidence of AF is reduced, but not eliminated by prophylaxis with beta-blockers. The limitations of prophylaxis with oral beta-blockers may be related to the delayed effect of oral therapy. We performed a pilot study of the efficacy of early intravenous esmolol and an oral beta-blocker regimen for prevention of postoperative AF.Methods: Fifty patients referred for CABG and considered to be at high risk for postoperative AF on the basis of prolonged signal-averaged ECG P wave duration 〉 140 ms were randomized to receive either a 24-hour infusion of esmolol 6–18 hours after CABG, at an average dose 67 ± 7 μ/kg/min, followed by oral beta-blockers versus oral beta-blockers only beginning on postoperative day 1.Results: Seven of 27 patients (26%) in the esmolol group and 6 of 23 patients (26%) in the oral beta-blocker group developed postoperative AF, P = NS. The mean time of onset of AF (2.7 ± 0.5 vs 2.7 ± 0.3 postoperative day, P = NS) and the median duration of AF (10 [2192] vs 7 [1.16] hours, P = NS) were similar between the two groups. Eleven (41%) patients treated with esmolol developed adverse events (hypotension: 8, bradycardia requiring temporary pacing: 2, left ventricular failure:1 patient) as compared to only one patient (4%) in the beta-blocker group who developed hypotension, P = 0.006.Conclusions: This randomized controlled pilot study suggests that intravenous esmolol is less well tolerated and offers no advantages to standard beta-blocker in preventing AF after CABG. A.N.E. 2002;7(2):86–91

Notes: BackgroundAtrial fibrillation is the most common arrhythmia encountered in clinical practice. Identification of factors predisposing to atrial fibrillation may have implications for its prevention and may facilitate the detection of patients most susceptible to atrial fibrillation and its sequelae. Prolongation of P wave duration representing intra-atrial conduction delay is inadequately visualized in a standard electrocardiogram. Accurate detection, alignment, amplification and filtering of P waves during the signal averaging process permits a better analysis of the P wave and thus atrial conduction. Signal averaged P wave electrocardiography is a noninvasive technique that has permitted the evaluation of patients at risk of developing atrial fibrillation. Several studies have correlated the abnormalities in signal averaged P wave with paroxysmal atrial fibrillation, and have demonstrated its utility in independently predicting patients at risk of developing atrial fibrillation following cardiac surgery. New uses are likely to evolve as the technique is used clinically and as the methodology is standardized. A.N.E. 1999;4(4):401–407