A Galvanizing Solution: Colonoscopy Bowel Preparation as a Trigger for Supraventricular Tachycardia

BACKGROUND

Polyethylene glycol (PEG)-based solutions are among the most commonly used bowel preparation regimens for colonoscopy. Although these solutions are well tolerated, rare adverse cardiac events have been reported.

OBJECTIVES

We sought to identify the characteristics that may predispose patients to develop supraventricular tachycardia (SVT) after ingestion of GoLYTELY (PEG 3350 and electrolytes oral solution) in anticipation for their colonoscopy.

METHODS

We performed a retrospective observational cohort study of the electronic medical record of all patients who developed SVT after ingestion of GoLYTELY solution from April 2012 to March 2019 at the John D. Dingell VA Medical Center. Clinical data were obtained through review of medical records.

RESULTS

We identified 16 patients with new-onset SVT after ingestion of bowel preparation solution before undergoing the colonoscopy procedure. In all, 12 (75%) patients developed atrial fibrillation, 3 (18.8%) patients developed atrial tachycardia, and 1 patient (6.3%) developed atrial flutter. Most patients were male (93.8%), and the mean age was 69 ± 8.2 years. The commonly associated comorbidities were hypertension (87.5%), hyperlipidemia (56.3%), and diabetes (37.5%). Laboratory testing demonstrated a normal electrolyte panel and thyroid stimulating hormone level. A significant percentage of patients had dilated atria and left-ventricular hypertrophy on echocardiogram.

CONCLUSION

Our case series suggests that there may be certain individuals who are predisposed to development of atrial arrhythmias, more so than others, after ingestion of PEG based solution for colonoscopy. We hypothesize that the combination of atrial dilation, sympathovagal discharge, and transient electrolyte shifts at the cellular level led to the development of SVTs.

The Impact of Personal Thoracic Impedance on Electrical Cardioversion in Patients with Atrial Arrhythmias

Background and Objectives: Direct current cardioversion (DCCV) is a safe and useful treatment for atrial tachyarrhythmias. In the past, the energy delivered in DCCV was decided upon empirically, based only on the type of tachyarrhythmia. This conventional method does not consider individual factors and may lead to unnecessary electrical damage. Materials and Methods: We performed DCCV in patients with atrial tachyarrhythmias. The impedance and electrical current at the moment of shock were measured. The human thoracic impedance between both defibrillator patches and the electric current that was used were measured. Results: A total of 683 DCCVs were performed on 466 atrial tachyarrhythmia patients. The average impedance was 64 ± 11 Ω and the average successful current was 23 ± 6 mA. The magnitude of the electrical current that was successful depended upon the human impedance (linear regression, B = −0.266, p < 0.001) and the left atrial diameter (B = 0.092, p < 0.001). Impedance was directly proportional to body mass index (BMI) (B = 1.598, p < 0.001) and was higher in females than in males (77 ± 15 Ω vs. 63 ± 11 Ω, p < 0.001). Notably, the high-impedance (>70 Ω) group had a higher BMI (27 ± 4 kg/m² vs. 25 ± 3 kg/m², p < 0.001) and a higher proportion of females (37% vs. 9%, p < 0.001) than the low-impedance group (<70 Ω). However, thoracic impedance was not an independent predictor for successful DCCV. Conclusions: Human thoracic impedance was one of the factors that impacted the level of electrical current required for successful DCCV in patients with atrial arrhythmias. In the future, it will be helpful to consider individual predictors, such as BMI and gender, to minimize electrical damage during DCCV.

Biosense Webster's QDOT Micro™ radiofrequency ablation catheter

The QDOT Micro™ catheter (Biosense Webster, Inc., CA, USA) is a new radiofrequency ablation catheter based on the SmartTouch SF™ (Biosense Webster, Inc.). It combines diffuse external irrigation with six thermocouples located within the outer metal shell and three additional microelectrodes in a 3.5 mm-tip contact force radiofrequency catheter. This article focuses on the different characteristics of the catheter, which incorporates the ability of high power delivery, irrigation flow control based on temperature sensing through the six thermocouples and the generation of microelectrograms. An outline of its performance in preclinical and clinical setting is presented, showing promising results, especially concerning procedural efficiency and short-term safety. Additional studies need to confirm long-term effectiveness, and durability studies should evaluate whether superiority on a lesion quality level can be achieved.

Case Reports: Emery-Dreifuss Muscular Dystrophy Presenting as a Heart Rhythm Disorders in Children

Emery-Dreifuss muscular dystrophy (EDMD) is inherited muscle dystrophy often accompanied by cardiac abnormalities in the form of supraventricular arrhythmias, conduction defects and sinus node dysfunction. Cardiac phenotype typically arises years after skeletal muscle presentation, though, could be severe and life-threatening. The defined clinical manifestation with joint contractures, progressive muscle weakness and atrophy, as well as cardiac symptoms are observed by the third decade of life. Still, clinical course and sequence of muscle and cardiac signs may be variable and depends on the genotype. Cardiac abnormalities in patients with EDMD in pediatric age are not commonly seen. Here we describe five patients with different forms of EDMD (X-linked and autosomal-dominant) caused by the mutations in EMD and LMNA genes, presented with early onset of cardiac abnormalities and no prominent skeletal muscle phenotype. The predominant forms of cardiac pathology were atrial arrhythmias and conduction disturbances that progress over time. The presented cases discussed in the light of therapeutic strategy, including radiofrequency ablation and antiarrhythmic devices implantation, and the importance of thorough neurological and genetic screening in pediatric patients presenting with complex heart rhythm disorders.

Optimal substrate modification strategies using catheter ablation in patients with persistent atrial fibrillation: 3-year follow-up outcomes

Objectives

This study aimed to assess the comparative efficacy of four ablation strategies on the incidence rates of freedom from atrial fibrillation (AF) or atrial tachycardia (AT) through a 3‐year follow‐up in patients with persistent AF.

Background

The optimal substrate modification strategies using catheter ablation for patients with persistent AF remain unclear.

Methods

Patients with persistent AF were enrolled consecutively to undergo each of four ablation strategies: (a) Group 1 (Gp 1, n = 69), pulmonary vein isolation (PVI) plus rotor ablation assisted by similarity index and phase mapping; (b) Gp 2 (n = 75), PVI plus linear ablations at the left atrium; (c) Gp 3 (n = 42), PVI plus the elimination of complex fractionated atrial electrograms; (d) Gp 4 (n = 67), PVI only. Potential confounders were adjusted via a multivariate survival parametric model.

Results

Baseline characteristics were similar across the four groups. At a follow‐up period of 34.9 ± 38.6 months, patients in Gp 1 showed the highest rate of freedom from AF compared with the other three groups (p = .002), while patients in Gp 3 and 4 showed lower rates of freedom from AT than those of the other two groups (p = .006). Independent predictors of recurrence of AF were the ablation strategy (p = .002) and left atrial diameter (LAD) (p = .01).

Conclusion

In patients with persistent AF, a substrate modification strategy using rotor ablation assisted by similarity index and phase mapping provided a benefit for maintaining sinus rhythm compared with the other strategies. Both ablation strategy and baseline LAD predicted the 3‐year outcomes of freedom from AT/AF

Efficacy and safety of ethanol infusion into the vein of Marshall for mitral isthmus ablation

INTRODUCTION

Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM-EI) can facilitate the achievement of mitral isthmus block. This study sought to describe the efficacy and safety of this technique.

METHODS AND RESULTS

Twenty-two consecutive patients (14 males, median age 71 years) with attempted VOM-EI for mitral isthmus ablation were included in the study. VOM-EI was successfully performed with a median of 4 ml of 96% ethanol in 19 patients (86%) and the mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM-EI was necessary for 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM-EI and terminated or slowed by VOM-EI in 4 and 3 patients, respectively. The low-voltage area of the mitral isthmus region increased from 3.1 cm² (interquartile range [IQR] 0-7.9) before to 13.2 cm² (IQR: 8.2-15.0) after VOM-EI and correlated significantly with the volume of ethanol injected (p = .03). Median high-sensitive cardiac troponin-T increased significantly from 330 ng/L (IQR: 221-516) the evening of the procedure to 598 ng/L (IQR: 382-769; p = .02) the following morning. A small pericardial effusion occurred in three patients (16%), mild pericarditis in one (5%), and uneventful VOM dissection in two (11%). After a median follow-up of 3.5 months (IQR: 3.0-11.0), 10 of 18 patients (56%) with VOM-EI and available follow-up had arrhythmia recurrence. Repeat ablation was performed in five patients (50%) and peri-mitral flutter diagnosed in three (60%).

CONCLUSION

VOM-EI is feasible, safe, and effective to achieve acute mitral isthmus block.

Electroanatomic Characterization and Ablation of Scar-Related Isthmus Sites Supporting Perimitral Flutter

OBJECTIVES

The authors reviewed 3-dimensional electroanatomic maps of perimitral flutter to identify scar-related isthmuses and determine their effectiveness as ablation sites.

BACKGROUND

Perimitral flutter is usually treated by linear ablation between the left lower pulmonary vein and mitral annulus. Conduction block can be difficult to achieve, and recurrences are common.

METHODS

Patients undergoing atrial tachycardia ablation using CARTO3 (Biosense Webster Inc., Irvine, California) were screened from 4 centers. Patients with confirmed perimitral flutter were reviewed for the presence of scar-related isthmuses by using CARTO3 with the ConfiDense and Ripple Mapping modules.

RESULTS

Confirmed perimitral flutter was identified in 28 patients (age 65.2 ± 8.1 years), of whom 26 patients had prior atrial fibrillation ablation. Scar-related isthmus ablation was performed in 12 of 28 patients. Perimitral flutter was terminated in all following correct identification of a scar-related isthmus using ripple mapping. The mean scar voltage threshold was 0.11 ± 0.05 mV. The mean width of scar-related isthmuses was 8.9 ± 3.5 mm with a conduction speed of 31.8 ± 5.5 cm/s compared to that of normal left atrium of 71.2 ± 21.5 cm/s (p < 0.0001). Empirical, anatomic ablation was performed in 16 of 28, with termination in 10 of 16 (63%; p = 0.027). Significantly less ablation was required for critical isthmus ablation compared to empirical linear lesions (11.4 ± 5.3 min vs. 26.2 ± 17.1 min; p = 0.0004). All 16 cases of anatomic ablation were reviewed with ripple mapping, and 63% had scar-related isthmus.

CONCLUSIONS

Perimitral flutter is usually easy to diagnose but can be difficult to ablate. Ripple mapping is highly effective at locating the critical isthmus maintaining the tachycardia and avoiding anatomic ablation lines. This approach has a higher termination rate with less radiofrequency ablation required.

Surgical management of a giant atrial septal aneurysm

We experienced a very rare case of surgical management of a giant atrial septal aneurysm. It is an interesting case and is supported by preoperative, intraoperative, and pathology images.

Case Report: Application of Thoracoscopic Clamp Radiofrequency Ablation on Atrial Tachycardia Originating From Right Atrial Appendage After Catheter Ablation Failure

Atrial tachycardia originating from the right atrial appendage has a higher probability of failure of catheter ablation. Here we report a case of a 13-year-old boy with incessant tachycardia, complicated by heart enlargement, and heart failure. Electrophysiological examination showed that atrial tachycardia (AT) originated from the apex of the right atrial appendage, and endocardial catheter ablation was ineffective. After thoracoscopic approach, the right atrial appendage was successfully ablated with bipolar radiofrequency ablation forceps, atrial tachycardia was terminated and sinus rhythm was restored. Within 3 months since the patient was discharged from the hospital, no arrhythmia occurred and the heart structure returned to normal. Thus, thoracoscopic clamp radiofrequency ablation may be a reasonable choice for young patients with atrial tachycardia originated from the right atrial appendage when transendocardial ablation is not effective.

Incessant Atrial Tachycardia as First Presentation of Cardiac Angiosarcoma

Primary cardiac angiosarcomas are rare malignant tumors with a very poor prognosis. We present a case of a 48-year-old man with no previous cardiac history who developed an incessant focal atrial tachycardia complicated by tachycardia-mediated cardiomyopathy as a consequence of cardiac angiosarcoma. (Level of Difficulty: Beginner.)

Atrial arrhythmia related outcomes in critically ill COVID-19 patients

Rationale

Coronavirus disease 2019 (COVID‐19) is associated with many clinical manifestations including respiratory failure and cardiovascular compromise.

Objectives

We examine outcomes in critically ill individuals with COVID‐19 who develop atrial tachyarrhythmias.

Methods

We collected data from electrocardiograms and the electronic medical record of COVID‐19 positive (COVID⁺) and negative (COVID⁻) individuals admitted to our medical intensive care unit between February 29 and June 28, 2020. We compared clinical and demographic characteristics, new onset atrial tachyarrhythmia, hemodynamic compromise following atrial tachyarrhythmia, and in‐hospital mortality in COVID⁺ versus COVID⁻. Hemodynamic compromise was defined as having a new or increased vasopressor requirement or the need for direct current cardioversion for hemodynamic instability within 1 hour of atrial tachyarrhythmia onset.

Results

Of 300 individuals included, 200 were COVID⁺ and 100 were COVID⁻. Mean age was 60 ± 16 years, 180 (60%) were males, and 170 (57%) were African American. New onset atrial tachyarrhythmia occurred in 16% of COVID⁺ and 19% of COVID⁻ individuals (P = .51). When compared to COVID⁻ participants without atrial tachyarrhythmia, COVID⁺ individuals with new onset atrial tachyarrhythmia had higher mortality after multivariable adjustment (OR 5.0, 95% CI 1.9–13.5). New onset atrial tachyarrhythmia was followed by hemodynamic compromise in 18 COVID⁺ but no COVID⁻ participants (P = .0001). COVID⁺ individuals with hemodynamic compromise after atrial tachyarrhythmia required increased ventilatory support at the time of atrial tachyarrhythmia onset.

Conclusions

Atrial tachyarrhythmia is associated with increased mortality in critically ill individuals with COVID‐19, especially those mechanically ventilated. Recognition of this could assist with clinical care for individuals with COVID‐19.

Evaluation of Directed Graph-Mapping in Complex Atrial Tachycardias

OBJECTIVES

Directed graph-mapping (DGM) is a novel operator-independent automatic tool that can be applied to the identification of the atrial tachycardia (AT) mechanism. In the present study, for the first time, DGM was applied in complex AT cases, and diagnostic accuracy was evaluated.

BACKGROUND

Catheter ablation of ATs still represents a challenge, as the identification of the correct mechanism can be difficult. New algorithms for high-density activation mapping (HDAM) render an easier acquisition of more detailed maps; however, understanding of the mechanism and, thus, identification of the ablation targets, especially in complex cases, remains strongly operator-dependent.

METHODS

HDAMs acquired with the latest algorithm (COHERENT version 7, Biosense Webster, Irvine, California) were interpreted offline by 4 expert electrophysiologists, and the acquired electrode recordings with corresponding local activation times (LATs) were analyzed by DGM (also offline). Entrainment maneuvers (EM) were performed to understand the correct mechanism, which was then confirmed by successful ablation (13 cases were centrifugal, 10 cases were localized re-entry, 22 cases were macro-re-entry, and 6 were double-loops). In total, 51 ATs were retrospectively analyzed. We compared the diagnoses made by DGM were compared with those of the experts and with additional EM results.

RESULTS

In total, 51 ATs were retrospectively analyzed. Experts diagnosed the correct AT mechanism and location in 33 cases versus DGM in 38 cases. Diagnostic accuracy varied according to different AT mechanisms. The 13 centrifugal activation patterns were always correctly identified by both methods; 2 of 10 localized reentries were identified by the experts, whereas DGM diagnosed 7 of 10. For the macro-re-entries, 12 of 22 were correctly identified using HDAM versus 13 of 22 for DGM. Finally, 6 of 6 double-loops were correctly identified by the experts, versus 5 of 6 for DGM.

CONCLUSIONS

Even in complex cases, DGM provides an automatic, fast, and operator-independent tool to identify the AT mechanism and location and could be a valuable addition to current mapping technologies.

The mechanisms of left septal and anterior wall reentrant atrial tachycardias analyzed with ultrahigh resolution mapping: The role of functional block in the circuit

BACKGROUND

Low voltage areas (LVAs) are most commonly observed on the left atrial (LA) septal/anterior wall.

OBJECTIVE

We explored the mechanisms of LA septal/anterior wall reentrant tachycardias (LASARTs) using ultrahigh resolution mapping.

METHODS

This study included seven consecutive LASARTs in six patients (75 [62.2-82.8] years, 4 women) who underwent atrial tachycardia (AT) mapping and ablation using Rhythmia systems.

RESULTS

The AT cycle length was 266 (239-321) ms. During ATs, 11.0 (9.0-12.9) cm² of LVAs were identified in all, and 0.8 (0.7-1.7) cm² of dense scar was identified in four patients. Five ATs rotated around dense scar, while two rotated around functional linear block, which was confirmed during atrial pacing after AT termination. The AT circuit length was 8.7 ± 2.1 cm with a conduction velocity of 30.4 ± 3.7 cm/s. A median of 3.0 (2.0-4.0) slow conduction areas per circuit were identified, and 17/23 (73.9%) areas were present in LVAs, while they were at the border of the LVA and normal voltage areas in the remaining 6/23 (26.1%). Global activation histograms facilitated the identification of the critical isthmus in all. Tailor-made ablation at critical isthmuses successfully eliminated all ATs. However, one patient with AT related to functional linear block experienced recurrent AT related to dense scar, which progressed after the procedure. During a mean 14 ± 13 month follow-up after the last procedure, no patients experienced recurrent ATs without any complications.

CONCLUSION

LASARTs consist of not only fixed conduction blocks but also functional conduction blocks. Ultrahigh resolution mapping is highly useful to decide the optimal tailor-made ablation strategy based on the mechanisms.

Effects of Ranolazine and its Combination with Amiodarone on Rapid Pacing-induced Reentrant Atrial Tachycardia in Rabbits

Ranolazine (RAN) has previously been shown to lower the onset of cholinergic atrial fibrillation in intact animals; however, its efficacy in the setting of atrial tachycardia (AT) is unknown. The purpose of this study was to investigate the effects of RAN alone or in combination with amiodarone (AMIO) on rapid pacing-evoked right AT in rabbit hearts. Right atrial monophasic action potentials (MAPs) were recorded in 11 anesthetized rabbits, using combination MAP pacing catheters. Vulnerability to AT was tested by employing consecutive trains of rapid burst pacing prior to and after 2.4 mg/kg of RAN alone delivered intravenously and then in combination with 3 mg/kg of AMIO as a 15-minute infusion. Primary endpoints were postdrug AT reproducibility as well as cycle length (CL) and tachycardia duration. MAP duration at 75% repolarization and the effective refractory period (ERP) were assessed during programmed pacing to calculate the atrial postrepolarization refractoriness (aPRR = ERP – MAPD_75%). AT was elicited in eight out of 11 rabbits; only these animals were included for further investigation. RAN did not abolish the inducibility of AT in any experiment; however, it prolonged its CL (baseline vs. RAN: 120 ± 16 ms vs. 138 ± 18 ms; p = 0.053). Supplemental AMIO further increased the AT CL (baseline vs. RAN + AMIO: 120 ± 16 ms vs. 152 ± 23 ms; p = 0.006), without affecting arrhythmia reinducibility. Slowing of the tachycardia after RAN or RAN + AMIO was associated with spontaneous termination of the arrhythmia. RAN prolonged the aPRR significantly, while AMIO in addition to RAN potentiated this effect. Neither RAN alone nor its combination with AMIO abolished the elicitation of AT in this model. However, both agents synergistically prolonged the aPRR, resulting in the slowing of AT and promoting spontaneous termination of the arrhythmia.

The characteristics and efficacy of catheter ablation of focal atrial tachycardia arising from an epicardial site

BACKGROUND

Although epicardial structures around the atrium such as adipose tissue possess arrhythmogenicity, little is known about atrial tachycardias (ATs) originating from epicardial sites (Epi-ATs). This study aimed to elucidate the prevalence, characteristics, and outcome after radiofrequency catheter ablation (RFCA) of Epi-ATs and to reveal the association between Epi-ATs and the epicardial structures.

METHODS

The electrocardiographic, electrophysiologic, and anatomical properties and results of RFCA were analyzed in 42 patients with a total of 49 ectopic ATs.

RESULTS

Six Epi-ATs (12%) were observed in six patients (14%). Four of six were respiratory cycle-dependent ATs and one was a swallowing-induced AT. The Epi-AT origins were adjacent to a pulmonary vein (five cases) and vein of Marshall (one case). A Valsalva maneuver or atropine infusion to define the arrhythmia mechanism affected the appearance of the Epi-ATs. The congruity rate between epicardial adipose tissue and the AT origin was significantly higher (100% vs. 44%, p = .045), and the epicardial adipose tissue volume of the atrium was significantly larger (104.1 vs. 64.6 ml, p = .04) in the Epi-AT group. Endocardial RFCA targeting the AT foci resulted in acute success in five of five cases. However, electrical isolation including of the AT foci resulted in acute failures (two of three cases) or a recurrence (one of one case).

CONCLUSIONS

Six Epi-ATs were associated with thoracic veins and epicardial arrhythmogenic structures. The main cause provoking the Epi-ATs was associated with autonomic nerve activity.

The effect of posterior wall isolation for persistent atrial fibrillation on recurrent arrhythmia

INTRODUCTION

It is important to consider recurrent arrhythmia after catheter ablation for persistent atrial fibrillation (AF) for planning an ablation strategy. However, the studies are limited to pulmonary vein isolation (PVI) plus posterior wall isolation (PWI), which were reported to improve procedural outcomes. The objective of this study is to evaluate the effect of PWI on recurrent arrhythmia.

METHODS

This is an observational study on patients with persistent AF comparing PVI plus PWI and PVI only strategies. In PVI plus PWI group, linear ablation of the left atrium roofline and bottom line were performed to achieve PWI after PVI. Some patients with AF recurrence underwent the second procedure. The presence of recurrent arrhythmia and results of the second procedures were evaluated.

RESULTS

A total of 181 patients (mean age, 66.9 ± 10.2 years; male, 76.8%) were included. PVI plus PWI group and PVI only group consisted of 90 and 91 patients, respectively. AF recurrence was observed in 28 of 90 (31.1%) patients with PVI plus PWI and in 43 of 91 (47.3%) with PVI only, and log-rank test did not show any significant difference (p = .35). The occurrence of recurrent persistent AF was significantly lower in PVI plus PWI group than in PVI only group (5/90; 5.6% vs. 18/91; 20.9%, p = .002). There was no significant difference between the two groups in recurrent paroxysmal AF and atrial tachycardia (AT).

CONCLUSION

PWI, in addition to PVI, for persistent AF was significantly related to fewer episodes of recurrent persistent AF, and it did not increase recurrent AT.

Systematic Evaluation of High-Resolution Activation Mapping to Identify Residual Endocardial and Epicardial Conduction Across the Mitral Isthmus

OBJECTIVES

This study sought to systematically evaluate the ability of a high-resolution mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) to rapidly and accurately localize residual endocardial and epicardial conduction after mitral isthmus (MI) ablation, facilitating MI block.

BACKGROUND

Achieving conduction block across the mitral isthmus (MI) is challenging.

METHODS

Fifty consecutive patients undergoing MI ablation after pulmonary vein isolation were enrolled. After initial endocardial radiofrequency (RF) ablation across the lateral MI, high-resolution activation mapping of the MI with simultaneous coronary sinus (CS) mapping was performed to verify block or localize residual conduction across the MI during left atrial (LA) appendage and CS pacing. Propagation maps were used to identify residual conduction across the MI as endocardial, via the CS or Marshall tract.

RESULTS

In all 50 patients, after the initial endocardial ablation across the MI, repeat high-resolution mapping of the LA and CS was obtained (median: 3,329 mapped points; 4.0 min of mapping time). The initial endocardial MI ablation resulted in block in 9 of 50 patients (18%). In the remaining 41 patients, the propagation map identified residual conduction in 4 patterns: 1) only endocardial gap in 12 patients (29%); 2) only CS connection in 10 patients (24%); 3) both endocardial and CS connections in 14 patients (34%); and 4) Marshall tract connection in 5 patients (12%). In 8 patients, the propagation map revealed residual conduction, despite differential atrial pacing suggesting bidirectional block. Focal ablation at the identified residual conduction site (median: 0.7 min of RF) resulted in block in 49 of 50 (98%) patients.

CONCLUSIONS

High-resolution propagation maps of the LA/CS rapidly and accurately localize residual endocardial and epicardial conduction across the MI. Focal ablation with short RF time at the identified gap(s) achieved complete block across MI in 98% of cases.

Incessant Focal Atrial Tachycardia Leading to Tachycardiomyopathy

A 22-year-old man presented with severe left ventricular (LV) dysfunction and progressive heart failure. The 12-lead electrocardiogram showed short runs of supraventricular tachycardia suggestive of focal atrial tachycardia. The patient underwent successful radiofrequency ablation. There was a complete recovery of symptoms and LV function at six months of follow-up. We discuss the importance of identifying tachycardiomyopathy as a reversible cause of heart failure.

Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: Treatment Strategy, Characteristics of Consecutive Atrial Tachycardia and Long-Term Outcome

Background

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and is associated with a deterioration of clinical status. Ablation of symptomatic AF is an established therapy, but in HCM, the characteristics of recurrent atrial arrhythmias and the long‐term outcome are uncertain.

Methods and Results

Sixty‐five patients with HCM (aged 64.5±9.9 years, 42 [64.6%] men) underwent AF ablation. The ablation strategy included pulmonary vein isolation in all patients and ablation of complex fractionated atrial electrograms or subsequent atrial tachycardias (AT) if appropriate. Paroxysmal, persistent AF, and a primary AT was present in 13 (20.0%), 51 (78.5%), and 1 (1.5%) patients, respectively. Twenty‐five (38.4%) patients developed AT with a total number of 54 ATs. Stable AT was observed in 15 (23.1%) and unstable AT in 10 (15.3%) patients. The mechanism was characterized as a macroreentry in 37 (68.5%), as a localized reentry in 12 (22.2%), a focal mechanism in 1 (1.9%), and not classified in 4 (7.4%) ATs. After 1.9±1.2 ablation procedures and a follow‐up of 48.1±32.5 months, freedom of AF/AT recurrences was demonstrated in 60.0% of patients. No recurrences occurred in 84.6% and 52.9% of patients with paroxysmal and persistent AF, respectively (P<0.01). Antiarrhythmic drug therapy was maintained in 24 (36.9%) patients.

Conclusions

AF ablation in patients with HCM is effective for long‐term rhythm control, and especially patients with paroxysmal AF undergoing pulmonary vein isolation have a good clinical outcome. ATs after AF ablation are frequently observed in HCM. Freedom of atrial arrhythmia is achieved by persistent AF ablation in a reasonable number of patients even though the use of antiarrhythmic drug therapy remains high.