Identification of 2 Distinct Boundaries Distinguishes Critical From Noncritical Isthmuses in Ablating Atypical Atrial Flutter.

BACKGROUND: Atypical atrial flutters often involve complex circuits. Classic methods of identifying ablation targets, including detailed electroanatomical mapping and entrainment within a well-defined isthmus, may not always be sufficient to allow the critical isthmus to be delineated and ablated, with flutter termination and prevention of reinduction. OBJECTIVES: This study sought a systematic method to classify conduction barriers and isthmuses as critical or noncritical that would improve understanding and ablation success. We also sought a construct unifying single- and dual-loop re-entry. Re-entrant circuits are bounded on 2 sides, although these are not consistently identified. We hypothesized 2 distinct critical boundaries, and a critical isthmus could be consistently defined without requiring entrainment, and ablation connecting these 2 boundaries would terminate tachycardia. METHODS: Activation maps were created electroanatomically. Conduction barriers were classified as noncritical barriers or critical boundaries. Critical boundaries showed sequential activation around the barrier, spanning ≥90% of the cycle length. Noncritical barriers showed nonsequential, parallel, or colliding activation or <90% of the cycle length. Only tissue separating the 2 critical boundaries defined a critical isthmus (CI); all others were considered noncritical. The effect of ablation across a CI was assessed. RESULTS: Complete maps were obtained in 128 cases in 121 patients (28 atypical right atrial, 100 left atrial). In all cases, 2 distinct critical boundaries were identified. Ablation across a CI connecting these critical boundaries terminated tachycardia in 123 of 128 cases (96.1%). Failures were due to inability to achieve block across the isthmus. CONCLUSIONS: Activation mapping of atypical atrial flutter allows consistent identification of 2 critical boundaries. Successful ablation connecting the 2 critical boundaries reliably results in termination of atypical atrial flutter.

The effect of catheter ablation for ventricular arrhythmias originating from the left ventricular papillary muscles on mitral valve function.

BACKGROUND: Ablation of ventricular arrhythmias (VA) originating from the left ventricular (LV) papillary muscles (PM) has the potential to damage the mitral valve apparatus resulting in mitral regurgitation (MR). This study sought to evaluate the effect of radiofrequency (RF) ablation of a PM on MR severity. METHODS: Patients with pre- and postablation transthoracic echocardiograms who underwent PM ablation for treatment of VA were retrospectively identified and compared to similar patients who underwent VA ablation at non-PM sites. MR severity was evaluated pre- and postablation in both groups and graded as none/trace (Grade 0); mild/mild-to-moderate (Grade 1); moderate (Grade 2); moderate-to-severe/severe (Grade 3). RESULTS: A total of 45 and 49 patients were included in the PM and non-PM groups, respectively. There were no significant baseline demographic differences. The PM group had longer RF ablation times (22.3 vs. 13.3 min, p < .01) compared to the non-PM group. Most patients had low-grade MR in both groups at baseline. Change in pre- versus postablation MR within the PM group was not statistically significant by Wilcoxon rank-sum test (Figure 2, p = .46). MR severity following ablation was also evaluated using logistic regression models. The odds ratio for worsening MR in the PM group compared to non-PM was 0.19 (95% confidence interval: 0.008-4.18, p = .29) after adjusting for comorbidities, LV ejection fraction, and LV internal end-diastolic diameter. CONCLUSION: RF ablation of VA originating from PM under intracardiac echocardiography guidance did not result in clinically or statistically significant worsening of MR.

Neurologic complications of atrial fibrillation: Pharmacologic and interventional approaches to stroke prevention.

Atrial fibrillation is a common cardiac arrhythmia that carries a risk of stroke. This is commonly stratified with the CHA2DS2-VASc score. Stroke risk can be reduced with anticoagulants or with interventions to close the left atrial appendage, the most common source of left atrial thrombi. While warfarin has been traditionally used as the only oral anticoagulant available, there are several direct oral anticoagulants that compare favorably with respect to both stroke and bleeding risk in randomized controlled trials. Multiple interventional options exist to close the left atrial appendage, but the Watchman device is the only one that compares favorably with warfarin in randomized controlled trials.

Procalcitonin as a Marker of Comorbid Atrial Fibrillation in Chronic Kidney Disease and History of Sepsis.

Cardiovascular disease and infection are the leading causes of mortality in patients with stage 5 chronic kidney disease on hemodialysis (CKD5-HD). Inflammation is a large component in the pathogenesis of both atrial fibrillation (AF) and sepsis and may link these conditions in CKD5-HD. Procalcitonin (PCT) is an inflammatory biomarker elevated in systemic infection and CKD5-HD, yet its value with regard to comorbid AF has not been thoroughly investigated. The aim of this study sought to evaluate circulating inflammatory markers, including PCT, Angiopoietin-1, Angiopoetin-2, CD40-L, C-reactive protein, d-dimer, and von Willebrand factor in relation to these conditions. Plasma levels of inflammatory markers were measured by enzyme linked immunosorbent assay method in CKD5-HD (n = 97) patients and controls (n = 50). Procalcitonin levels were significantly elevated (P = .0270) in CKD5-HD with comorbid AF compared to those without AF. Further analysis of patients with a history of sepsis demonstrated significantly elevated levels of PCT (P = .0405) in those with comorbid AF (160.7 ± 39.5 pg/mL) compared to those without AF (117.4 ± 25.3 pg/mL). This study demonstrates that the inflammatory biomarker PCT is further elevated in the presence of both AF and a history of sepsis in hemodialysis patients and suggests that underlying chronic inflammation following sepsis resolution may place these patients at greater risk of developing AF.

Wolff-Parkinson-White, Brugada phenocopy, and flecainide toxicity: All in one patient.

Accessory pathway Wolff-Parkinson-white is sometimes not manifested till later in life, as the conduction properties of AV node become slower, other mechanisms are also possible. Brugada pattern on EKG can be associated with various underlying clinical conditions, such as mechanical compression of RVOT by tumors. It is essential to have high index of suspicion for flecainide toxicity when encountering arrhythmias in patients taking the drug.

Neurologic complications of catheter ablation/defibrillators/pacemakers.

Approaches to the management of patients with cardiac arrhythmias have significantly evolved over the last decade, with advancement in catheter ablation and device implantation techniques. As the techniques and tools evolve, so does our understanding of the possible complications from these procedures. The focus of this chapter is discussion of the neurologic complications involved with catheter ablation, pacemaker and defibrillation implantation, with the focus on timely diagnosis, and management strategies.

Prospective study of cardiac sarcoid mimicking arrhythmogenic right ventricular dysplasia.

INTRODUCTION: Case studies indicate that cardiac sarcoid may mimic the clinical presentation of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C); however, the incidence and clinical predictors to diagnose cardiac sarcoid in patients who meet International Task Force criteria for ARVD/C are unknown. METHODS AND RESULTS: Patients referred for evaluation of left bundle branch block (LBBB)-type ventricular arrhythmia and suspected ARVD/C were prospectively evaluated by a standardized protocol including right ventricle (RV) cineangiography-guided myocardial biopsy. Sixteen patients had definite ARVD/C and four had probable ARVD/C. Three patients were found to have noncaseating granulomas on biopsy consistent with sarcoid. Age, systemic symptoms, findings on chest X-ray or magnetic resonance imaging (MRI), type of ventricular arrhythmia, RV function, ECG abnormalities, and the presence or duration of late potentials did not discriminate between sarcoid and ARVD/C. Left ventricular dysfunction (ejection fraction <50%) was present in 3/3 patients with cardiac sarcoid, but only 2/17 remaining patients with definite or probable ARVD/C (P = 0.01). CONCLUSIONS: In this prospective study of consecutive patients with suspected ARVD/C evaluated by a standard protocol including biopsy, the incidence of cardiac sarcoid was surprisingly high (15%). Clinical features, with the exception of left ventricular dysfunction and histological findings, did not discriminate between the two entities.

Posterior myocardial infarction: unique diagnosis to an elusive problem.

The clinical presentation of posterior myocardial infarction is not easy. The diagnosis is often missed due to lack of ST-segment elevation in standard 12-lead electrocardiogram. The diagnosis is made by seeing ST-segment elevation in the posterior leads V7, V8, and V9, which are typically placed in the left posterior axillary line, left midscapular line, and halfway between the mid scapular and left paraspinal line, respectively. The investigators describe a case of posterior myocardial infarction where additional posterior leads were placed in the left paraspinal line, right paraspinal line, and right midscapular line, displaying more prominent current of injury than seen with traditional posterior lead placement. This may lead to a more robust identification of posterior myocardial infarction that, in turn, may allow for adequate treatment and triage.

A quality guarantee in acute coronary syndromes: the American College of Cardiology's Guidelines Applied in Practice program taken real-time.

BACKGROUND: Wide variation exists in the management of acute coronary syndromes (ACSs), which includes an apparent underutilization of evidence-based therapies. We have previously demonstrated that application of the American College of Cardiology Guidelines Applied in Practice (GAP) tools can improve quality indicator rates and outcomes of patients hospitalized with ACS. OBJECTIVE: To determine whether a real-time system for monitoring key quality-of-care indicators using GAP would improve both process indicators and outcomes beyond those of the initial implementation of GAP. DESIGN: Prospective patient identification, prospective chart coding, retrospective data abstraction. PATIENTS: All patients with ACS admitted (N = 3189) to our institution between January 1, 1999, and December 2004; 2019 studied before real-time implementation from January 1, 1999, to June 30, 2002, and 1170 studied during real-time implementation from July 1, 2002, to December 31, 2004. MAIN OUTCOME MEASURE: The effect of real-time monitoring of key quality indicators on inhospital therapy and outcomes, and 6-month outcomes in patients admitted with ACS. RESULTS: The real-time GAP implementation correlated with more frequent use of inhospital angiotensin-converting enzyme inhibitors (72.7% vs 63.7%, P < .0001), beta blockers (93.0% vs 89.7%, P = .0016), statins (81.2% vs 65.9%, P < .0001), antiplatelet agents (69.2% vs 22.5%, P < .0001), and glycoprotein IIb/IIIa inhibitors (35.5% vs 26.7%, P < .0001). There were fewer episodes of inhospital congestive heart failure (3.85% vs 8.77%, P < .0001) and major bleeding events (3.2% vs 7.9%, P < .0001) after the real-time system was adopted. Real-time GAP also resulted in higher discharge rates of aspirin (92.1% vs 86.5%, P < .0001), beta blockers (86.8% vs 79.1%, P < .0001), statins (81.2% vs 64.7%, P < .0001), and angiotensin-converting enzyme inhibitors (67.1% vs 55.5%, P < .0001). Real-time GAP implementation was associated with fewer rehospitalizations for heart disease (19.8% vs 25.2%, P = .0014), myocardial infarction (3.5% vs 5.4%, P = .0243), and combined death/cerebrovascular accident/myocardial infarction (9.5% vs 13.9%, P = .0009) during the first 6 months after discharge. CONCLUSION: The institution of a formal system to review and "guarantee" key quality-of-care indicators real time in the hospital is associated with improved outcomes in patients admitted with ACS. The combination of American College of Cardiology's GAP program and its real-time implementation leads to higher use of evidence-based therapies and correspondingly better outcomes than those associated with the initial GAP implementation.