Rapid detection of isthmus block and rhythm change using local electrogram changes during complex atrial flutter ablation.

AIMS: Multiple re-entry circuits may operate simultaneously in the atria in the form of dual loop re-entry using a common isthmus, or multiple re-entrant loops without a common isthmus. When two or more re-entrant circuits coexist, ablation of an individual isthmus may lead to a seamless transition (without significant changes in surface electrocardiogram, coronary sinus activation or tachycardia cycle length) to a second rhythm, and the isthmus block can go unnoticed. METHODS AND RESULTS: We hypothesize and subsequently illustrate in three patient cases, methods to rapidly identify a transition in the rhythm and isthmus block using local electrogram changes at the ablation site. CONCLUSION: Local activation sequence changes, electrogram timing, and the behaviour of pre-existing double potentials can reveal isthmus block promptly when rhythm transitions occur during ablation of multiloop re-entry tachycardias.

Diagnostic utility of early premature ventricular complexes in differentiating atrioventricular reentrant and atrioventricular nodal reentrant tachycardias.

BACKGROUND: His-refractory premature ventricular complexes perturbing a supraventricular tachycardia (SVT) establish the presence of an accessory pathway (AP). Earlier premature ventricular complexes (ErPVCs) may perturb SVTs but are considered nondiagnostic. OBJECTIVE: The purpose of this study was to test the hypothesis that an ErPVC will always show a difference >35 ms in its advancement of the next atrial activation during atrioventricular nodal reentrant tachycardia (AVNRT). During atrioventricular reentrant tachycardia (AVRT), a PVC delivered close to the circuit can result in greater advancement of atrial activation due to retrograde conduction via an AP. Thus, an AP response, defined as ErPVC (H1S2) advancing the subsequent atrial activation (A1-A2) more than this minimum difference (A1A2 ≤ H1S2+35 ms), establishes the presence of an AP. METHODS: Sixty-five consecutive patients with SVT were retrospectively evaluated. ErPVCs were defined when the ventricular pacing stimulus was >35 ms ahead of the His during tachycardia. RESULTS: Among the 65 cases, 43 were AVNRT and 22 AVRT. Fourteen AVRT cases had an AP response with a mean H1S2+35 ms of 336 ± 58 ms and A1A2 of 309 ± 51ms. No AVNRT cases had an AP response. The specificity of an AP response to ErPVC in predicting AVRT was 100%. CONCLUSION: An AP response to PVCs (A1A2 ≤ H1S2+35 ms) is 100% specific for the presence of an AP.

Left atrial hypertension and the risk of early incident heart failure after atrial fibrillation ablation.

INTRODUCTION: Elevated left atrial pressure (LAP) during catheter ablation of atrial fibrillation (AF) is associated with an increased risk of AF recurrence, but it is unknown if this correlates with heart failure (HF). The objective of the study was to determine if elevated LAP after AF ablation correlates with HF events. METHODS: Prospective, single-center, cohort study measuring LAP and right atrial pressure (RAP) during AF ablation in 100 patients. The primary endpoint was clinical HF within 30 days of ablation. The secondary outcome was AF-free HF. RESULTS: One hundred patients (63% male, mean age 64.5) were enrolled and 20% had clinical HF within 30 days. Bivariate correlates included mitral valve (MV) disease, persistent AF, class III antiarrhythmics, LAP, and recurrent AF. Multivariate analysis revealed class III antiarrhythmics were protective (odds ratio [OR]: 0.24 [0.1-0.5], p = .04), while MV disease (OR: 8.7 [3.3-23], p = .03) and loop diuretics (OR: 4.8 [2.6-9.1], p = .01) were hazardous. AF-free HF occurred in 9% of patients and correlated with higher LAP and RAP, and chronic kidney disease. CONCLUSION: Patients with HF after AF ablation had higher LAP. MV disease, diuretic use, and class III antiarrhythmics also correlated to HF. These present opportunities to target future interventions to reduce a common complication of AF ablation.

Avoiding Bladder Catheters During Atrial Fibrillation Ablation.

OBJECTIVES: This study sought to determine if atrial fibrillation (AF) ablation can be performed safely without bladder catheterization. BACKGROUND: Patients undergoing AF ablation often receive bladder catheters. Catheterization is associated with potential complications. The ABCD-AF (Avoiding Bladder Catheters During Atrial Fibrillation) ablation study evaluates the advantages of performing AF ablation without routine catheterization. METHODS: In this single-center, prospective, randomized controlled trial, 80 patients received bladder catheterization (group A), and 80 patients received only as-needed catheterization (group B). The primary endpoint was a composite of cystitis, urethral injury, hematuria, dysuria, or urinary retention. RESULTS: The mean patient age was 63 ± 13 years, and 33% of patients were female. The primary outcome was reached in 45 patients in group A and 11 patients in group B (p < 0.001). Urinary tract infection occurred in 7 patients in group A and 2 patients in group B (p = 0.17). Urinary retention occurred in 12 patients in group A and 5 patients in group B (p = 0.07). Randomization to catheterization carried an odds ratio of 8.1 (95% confidence interval [CI]: 3.7 to 17.5; p < 0.001), and male sex carried an odds ratio of 3.8 (95% CI: 1.7 to 8.6; p = 0.001) for the primary endpoint. On subgroup analysis, randomization to undergo catheterization had no association with the primary outcome in female patients but had an odds ratio of 14.6 (95% CI: 5.6 to 38.1; p < 0.001) in male patients. In multivariable analysis, sex and catheter status remained independently associated with the primary outcome. CONCLUSIONS: Bladder catheterization can be safely avoided in patients undergoing AF ablation and is associated with a significant reduction in adverse outcomes, especially in men.

Utility of mobile cardiac outpatient telemetry for the diagnosis of palpitations, presyncope, syncope, and the assessment of therapy efficacy.

INTRODUCTION: Continuous mobile cardiac outpatient telemetry (MCOT) may have several advantages over traditional ambulatory monitoring systems in the diagnostic evaluation of symptoms such as palpitations, dizziness, and syncope. However, only limited published data are available showing its advantages. METHODS AND RESULTS: We reviewed the records of 122 consecutive patients evaluated using MCOT for palpitations, presyncope/syncope, or to monitor the efficacy of a specific antiarrhythmic therapy. Ten of 17 patients (59%) studied for presyncope/syncope had a diagnosis made with MCOT. Eight of these 17 patients had a previous negative evaluation for presyncope/syncope and five had an event correlated with the heart rhythm during the monitoring period. Nineteen patients monitored for palpitations or presyncope/syncope were asymptomatic during monitoring but had a prespecified arrhythmia detected. When MCOT was used as the first ambulatory monitoring system to evaluate palpitations (n = 18), 73% of patients correlated their symptoms with the underlying cardiac rhythm. Seven of 21 patients monitored for medication titration had dosage adjustments during outpatient monitoring. CONCLUSIONS: MCOT can detect asymptomatic clinically significant arrhythmias, and was especially useful to identify the cause of presyncope/syncope, even in patients with a previous negative workup. This outpatient monitoring system allows patients to undergo daily medication dose titration in the outpatient setting, thus avoiding hospitalization.