Paradigm Shifts in Cardiac Care: Lessons Learned From COVID-19 at a Large New York Health System.

The coronavirus disease-2019 (COVID-19) pandemic has overwhelmed healthcare systems around the world, resulting in morbidity, mortality, and a dramatic economic downturn In the United States. Urgent responses to the pandemic halted routine hospital workflow in an effort to increase hospital capacity, maintain staffing, and ration protective gear. Most notably, New York saw the largest surge of COVID-19 cases nationwide. Healthcare personnel and physician leaders at Northwell Health, the largest healthcare system in New York, have worked together to successfully implement operational changes resulting in a paradigm shift in cardiac care delivery. In this manuscript, we detail specific protocol adjustments made in our cardiology department, cardiology service line, and healthcare system in the face of the COVID-19 pandemic. We discuss the sustainability of this shift moving forward and the opportunity to optimize care for cardiovascular patients in the post COVID-19 era.

Mindfulness and Interoceptive Exposure Therapy for Anxiety Sensitivity in Atrial Fibrillation: A Pilot Study.

Atrial fibrillation is the most common cardiac arrhythmia and symptoms overlap with physiological sensations of anxiety. Patients with atrial fibrillation can demonstrate anxiety sensitivity even in the absence of actual atrial fibrillation symptoms. Interoceptive exposure is effective in treating anxiety sensitivity, and recently, mindfulness has been proposed as an enhancement strategy to facilitating inhibitory learning in exposure therapy. This pragmatic study piloted a brief mindfulness and interoceptive exposure treatment for anxiety sensitivity in atrial fibrillation. Eight participants with atrial fibrillation and elevated anxiety sensitivity from a hospital cardiology department participated in the treatment. Anxiety sensitivity significantly decreased during the course of the intervention. These initial findings show proof of concept for this brief intervention in a cardiac-specific behavioral medicine setting.

Guidance for Rebooting Electrophysiology Through the COVID-19 Pandemic From the Heart Rhythm Society and the American Heart Association Electrocardiography and Arrhythmias Committee of the Council on Clinical Cardiology: Endorsed by the American College of Cardiology.

Coronavirus disease 2019 (COVID-19) has presented substantial challenges to patient care and impacted health care delivery, including cardiac electrophysiology practice throughout the globe. Based upon the undetermined course and regional variability of the pandemic, there is uncertainty as to how and when to resume and deliver electrophysiology services for arrhythmia patients. This joint document from representatives of the Heart Rhythm Society, American Heart Association, and American College of Cardiology seeks to provide guidance for clinicians and institutions reestablishing safe electrophysiological care. To achieve this aim, we address regional and local COVID-19 disease status, the role of viral screening and serologic testing, return-to-work considerations for exposed or infected health care workers, risk stratification and management strategies based on COVID-19 disease burden, institutional preparedness for resumption of elective procedures, patient preparation and communication, prioritization of procedures, and development of outpatient and periprocedural care pathways.

Loop Recorder Implantation on a Telemetry Ward.

The implantable loop recorder (ILR) is a valuable tool used in the evaluation of syncope, arrhythmia, and cryptogenic stroke. In the inpatient setting, ILRs are routinely implanted in the electrophysiology (EP) lab despite the low complication rate. The purpose of this study was to evaluate the safety, feasibility, and cost of implanting ILRs at the patient's bedside by both electrophysiologists and advanced practice providers (APPs). This was a single center, retrospective study of consecutive ILR implantations performed from February 2018 to May 2019. We examined 3 groups: implantations in the EP lab by electrophysiologists (EP Lab/MD), implantations at the bedside by electrophysiologists (Floor/MD), and implantations at the bedside by APPs (Floor/APP). Over 15 months, 152 patients underwent ILR implantation: 48 in the EP Lab/MD group, 57 in the Floor/MD group, and 47 in the Floor/APP group. The procedure duration was longer in the Floor/APP group (14.2 ± 5.9 minutes) compared with the EP Lab/MD and Floor/MD groups (6.8 ± 4.3 minutes, 9.1 ± 4.9 minutes, p <0.001). The overall complication rate was low (2.6%) with no differences between the groups (p = 0.83). The calculated costs per implant for the EP Lab/MD group, Floor/MD group, and Floor/APP group were $482.05, $162.82, and $73.08, respectively.

Sites With Small Impedance Decrease During Catheter Ablation for Atrial Fibrillation Are Associated With Recovery of Pulmonary Vein Conduction.

OBJECTIVE: To correlate impedance decrease during atrial fibrillation (AF) ablation with lesion durability and PV conduction recovery demonstrated during redo procedures. BACKGROUND: Markers of successful ablation beyond acute conduction block are needed to improve durability of pulmonary vein (PV) isolation (PVI). Local impedance decrease resulting from ablation is a real-time marker of tissue heating and is correlated with lesion creation. METHODS: Impedance changes associated with point-by-point radiofrequency ablation in the PV antra were recorded during 167 consecutive first-time AF ablations. During clinically indicated redo procedures, sites of recovered PV conduction were identified, and were correlated with the impedance change achieved during ablation at these locations during the initial procedure. RESULTS: Redo procedures were performed in 28 patients, in whom 19 sites of recovered PV conduction were documented. Most sites of PV reconnection (58%) occurred along the posterior PV antra. Ablation resulting in impedance decrease <10 ohms during the initial procedure was present in 89% (17/19) of sites with conduction recovery. Regions with adjacent ablation resulting in impedance decrease <10 ohms were associated with a higher rate of conduction recovery (37% vs. 1.5%, P < 0.001). Likewise, patients with PV conduction recovery demonstrated during redo procedure (Group 1) had larger regions where ablation resulted in <10 ohm impedance decrease than patients without PV conduction recovery (Group 2) (21.9 ± 15.5 mm vs. 11.5 ± 2.1 mm, P < 0.01). CONCLUSION: Recovered PV conduction occurs predominantly in regions where adjacent ablation applications result in impedance decreases <10 ohms. Impedance-guided ablation strategies may improve durability of PVI.

Electrogram analysis and pacing are complimentary for recognition of abnormal conduction and far-field potentials during substrate mapping of infarct-related ventricular tachycardia.

BACKGROUND: Mapping to identify scar-related ventricular tachycardia re-entry circuits during sinus rhythm focuses on sites with abnormal electrograms or pace-mapping findings of QRS morphology and long stimulus to QRS intervals. We hypothesized that (1) these methods do not necessarily identify the same sites and (2) some electrograms are far-field potentials that can be recognized by pacing. METHODS AND RESULTS: From 12 patients with coronary disease and recurrent ventricular tachycardia undergoing catheter ablation, we retrospectively analyzed electrograms and pacing at 546 separate low bipolar voltage (<1.5 mV) sites. Electrograms were characterized as showing evidence of slow conduction if late potentials (56%) or fractionated potentials (76%) were present. Neither was present at (13%) sites. Pacing from the ablation catheter captured 70% of all electrograms. Higher bipolar voltage and fractionation were independent predictors for pace capture. There was a linear correlation between the stimulus to QRS duration during pacing and the lateness of a capturing electrogram (P<0.001), but electrogram and pacing markers of slow conduction were discordant at 40% of sites. Sites with far-field potentials, defined as those that remained visible and not captured by pacing stimuli, were identified at 48% of all pacing sites, especially in areas of low bipolar voltage and late potentials. Initial radiofrequency energy application rendered 74% of targeted sites electrically unexcitable. CONCLUSIONS: Far-field potentials are common in scar areas. Combining analysis of electrogram characteristics and assessment of pace capture may refine identification of substrate targets for radiofrequency ablation.

Anterograde conduction to the His bundle during right ventricular overdrive pacing distinguishes septal pathway atrioventricular reentry from atypical atrioventricular nodal reentrant tachycardia.

BACKGROUND: Distinguishing orthodromic atrioventricular reciprocating tachycardia (ORT) using a retrograde septal accessory pathway (AP) from atypical atrioventricular nodal reentrant tachycardia (AVNRT) may be challenging. Specifically, excluding the presence and participation of an AP may require multiple diagnostic maneuvers. OBJECTIVE: The purpose of this study was to assess the relative value of commonly used right ventricular (RV) pacing maneuvers, including identification of anterograde His-bundle activation with entrainment, to differentiate ORT using a retrograde septal AP from atypical AVNRT. METHODS: From March 2009 to June 2014, 56 patients (28 female; age 43.9 ± 17.4 years) who underwent electrophysiologic study and ablation for supraventricular tachycardia (26 ORT using septal AP and 30 atypical AVNRT) that exhibited a concentric atrial activation pattern and a septal ventriculoatrial interval >70 ms were analyzed. RESULTS: Overdrive pacing maneuvers or ventricular extrastimuli failed on at least 1 occasion to correctly identify a septal AP. Overall, 16 ORT patients and 26 AVNRT patients had successful RV entrainment, and 12 (75%) ORT patients showed anterograde His capture (11 patients) and/or anterograde septal ventricular capture (3 patients). None of the patients with atypical AVNRT showed anterograde conduction to the His bundle with entrainment. CONCLUSION: RV pacing maneuvers are useful to exclude an AP in patients with AVNRT having concentric atrial activation sequence and a septal ventriculoatrial interval >70 ms; however, none are consistently diagnostic. When observed in this patient population, anterograde His-bundle or septal ventricular capture during RV entrainment was diagnostic for ORT using a septal AP.

Ventricular tachycardia in cardiac sarcoidosis: characterization of ventricular substrate and outcomes of catheter ablation.

BACKGROUND: Cardiac sarcoid-related ventricular tachycardia (VT) is a rare disorder; the underlying substrate and response to ablation are poorly understood. We sought to examine the ventricular substrate and outcomes of catheter ablation in this population. METHODS AND RESULTS: Of 435 patients with nonischemic cardiomyopathy referred for VT ablation, 21 patients (5%) had cardiac sarcoidosis. Multiple inducible VTs were observed with mechanism consistent with scar-mediated re-entry in all VTs. Voltage maps showed widespread and confluent right ventricular scarring. Left ventricular scarring was patchy with a predilection for the basal septum, anterior wall, and perivalvular regions. Epicardial right ventricular scar overlay and exceeded the region of corresponding endocardial scar. After ≥1 procedures, ablation abolished ≥1 inducible VT in 90% and eliminated VT storm in 78% of patients; however, multiple residual VTs remained inducible. Failure to abolish all inducible VTs was because of septal intramural circuits or extensive right ventricular scarring. Multiple procedure VT-free survival was 37% at 1 year, but VT control was achievable in the majority of patients with fewer antiarrhythmic drugs compared with preablation (2.1±0.8 versus 1.1±0.8; P<0.001). CONCLUSIONS: Patients with cardiac sarcoidosis and VT exhibit ventricular substrate characterized by confluent right ventricular scarring and patchy left ventricular scarring capable of sustaining a large number of re-entrant circuits. Catheter ablation is effective in terminating VT storm and eliminating ≥1 inducible VT in the majority of patients, but recurrences are common. Ablation in conjunction with antiarrhythmic drugs can help palliate VT in this high-risk population.

Ventricular arrhythmias near the distal great cardiac vein: challenging arrhythmia for ablation.

BACKGROUND: Catheter ablation for ventricular arrhythmia (VA) near the distal great cardiac vein (GCV) is often challenging, and data are limited. METHODS AND RESULTS: Analysis was performed in 30 patients (19 men; age, 52.8±15.5 years) who underwent catheter ablation for focal VA (11 ventricular tachycardia and 19 premature contractions) with early activation in the GCV (36.7±8.0 ms pre-QRS). Angiography in 27 patients showed earliest GCV site within 5 mm of a coronary artery in 20 (74%). Ablation was performed in the GCV in 15 patients and abolished VA in 8. Ablation was attempted at adjacent non-GCV sites in 19 patients and abolished VA in 5 patients (4 from the left ventricular endocardium and 1 from the left coronary cusp); all success had VA with an initial r wave in lead I and activation ≤7 ms after the GCV (GCV-non-GCV interval). In 13 patients, percutaneous epicardial mapping was performed, but because of adjacent coronaries only 2 received radiofrequency application with VA elimination in 1. Surgical cryoablation was performed in 3 patients and abolished VA in 2. Overall acute success was achieved in 16 (53%) patients. After a median of 2.8 months, 13 patients remained free of VA. Major complications occurred in 4 patients, including coronary injury requiring stenting. CONCLUSIONS: Ablation for this arrhythmia is challenging and often limited by the adjacent coronary vessels. Success of anatomically guided endocardial ablation may be identified by a short GCV-non-GCV interval and r wave in lead I.

Overdrive pacing from downstream sites on multielectrode catheters to rapidly detect fusion and to diagnose macroreentrant atrial arrhythmias.

BACKGROUND: Entrainment criteria for macroreentrant arrhythmias are based on detecting fusion between tachycardia and paced wavefronts, but this is often difficult for atrial tachycardias (AT) after ablation of atrial fibrillation. METHODS AND RESULTS: With the use of a multipolar catheter, pacing was performed from electrodes within the coronary sinus showing activation later than adjacent electrodes (downstream overdrive pacing) during 66 ATs in 62 patients: 20 cavotricuspid isthmus-dependent ATs, 20 perimitral ATs, 13 focal ATs with sequential coronary sinus activation, and 13 other macroreentrant left atrial ATs. The paced cycle length was 10 to 30 milliseconds below the tachycardia cycle length (TCL), and activation at the neighboring upstream electrodes was assessed. Downstream overdrive pacing at 48 sites close to a macroreentrant circuit (PPI-TCL <40 milliseconds, where PPI is postpacing interval) produced constant fusion demonstrated by a long stimulus to upstream atrial electrogram interval (S-Au) >75% TCL and was consistent with orthodromic activation of the upstream site despite its close proximity to the pacing site. In contrast, downstream overdrive pacing at 18 sites during focal AT or remote from the macroreentrant AT circuit (PPI-TCL >40 milliseconds) always demonstrated a comparatively short S-Au <25% of TCL (12±4% versus 89±4% of TCL; P<0.001), consistent with direct activation. CONCLUSIONS: Selection of a downstream activation site for overdrive pacing can facilitate rapid recognition of macroreentry and proximity to the reentry circuit using a single multielectrode catheter by recognizing a PPI-TCL <40 milliseconds and S-Au >75% of TCL. Recognition of intracardiac constant fusion with this method is a novel criterion for transient entrainment.

Reentrant ventricular tachycardia originating from the periaortic region in the absence of overt structural heart disease.

BACKGROUND: In the absence of overt structural heart disease, most left ventricular outflow tract ventricular tachycardias (VTs) have a focal origin and are benign. We hypothesized that multiple morphologies (MMs) of inducible left ventricular outflow tract VT may indicate a scar-related VT that can mimic idiopathic VT. METHODS AND RESULTS: Of 54 consecutive patients referred for ablation of sustained outflow tract VT without overt structural heart disease, 24 had left ventricular outflow tract VT, 10 had MM VT, and 14 had a single VT (SM). The MM group were older (70.3±4.3 versus 53.9±15.9 years; P=0.004), had more hypertension (100% versus 29%; P=0.0006), and had longer PR intervals and QRS durations compared with the SM group. In contrast to the SM group, the MM group VTs had features consistent with reentry, including induction by programmed stimulation without isoproterenol, entrainment in some, and abnormal electrograms in the periaortic area. Periaortic region voltages suggested scar in the MM group, but not in the SM group. MRI in 2 MM patients was consistent with scar, but not in 10 SM patients. Longer radiofrequency applications were required in the MM group than in the SM group. At a median follow-up of 9.7 (3.0-32.0) months, recurrences tended to be more frequent in the MM group than in the SM group (70% versus 22%; P=0.07). CONCLUSIONS: VTs from small regions of periaortic scar can mimic idiopathic VT but are suggested by multiple VT morphologies and are more difficult to ablate. Whether these patients are at greater risk, as feared for other scar-related VTs, warrants further study.

Catheter ablation of ventricular tachycardia in nonischemic heart disease.

BACKGROUND: Catheter ablation of ventricular tachycardia (VT) in nonischemic heart diseases can be challenging, and outcomes across different diseases are incompletely defined. The aim of this study was to describe the outcomes after catheter ablation for nonischemic VT in a large cohort and to compare the electrophysiological findings and outcomes according to the type of underlying disease. METHODS AND RESULTS: Of the 891 consecutive patients undergoing catheter ablation for ventricular arrhythmias, 226 patients (52 ± 14 years; 79% men) with sustained VT due to nonischemic heart disease were included. The primary end point was all-cause death or heart transplantation. Secondary end points were a composite of death, heart transplantation, or readmission because of VT recurrence within 1 year of discharge. Underlying heart diseases were dilated cardiomyopathy in 119 (53%), valvular heart disease in 34 (15%), arrhythmogenic right ventricular cardiomyopathy in 37 (16%), congenital heart disease in 16 (7%), cardiac sarcoidosis in 13 (6%), and hypertrophic cardiomyopathy in 7 (3%) patients. After ablation, inability to induce any VT was achieved in 55%, and another 20% had inducible VTs modified. Major complications occurred in 5%. Arrhythmogenic right ventricular cardiomyopathy had better outcomes than dilated cardiomyopathy for primary (P=0.002) and secondary end points (P=0.004). Sarcoidosis had worse outcome than dilated cardiomyopathy for secondary end point (P=0.002). At 1 year after the last ablation (a mean of 1.4 ± 0.6 procedures, 1-4), freedom from death, heart transplantation, and readmission for VT recurrence were achieved in 173 (77%) patients. CONCLUSIONS: In patients with recurrent VT due to nonischemic heart disease, catheter ablation is often useful, although the outcome varies according to the nature of the underlying heart disease.

Transcoronary ethanol ablation for recurrent ventricular tachycardia after failed catheter ablation: an update.

BACKGROUND: Despite substantial progress, radiofrequency catheter ablation (RFCA) fails in some patients. After encouraging results with transcoronary ethanol ablation (TCEA), we began offering TCEA routinely when endocardial and epicardial RFCA failed or a deep intramural substrate was likely. METHODS AND RESULTS: Among 274 consecutive patients who underwent 408 ventricular tachycardia (VT) ablation procedures, 27 patients (21 men; age, 63 ± 13 years; left ventricular ejection fraction, 30 ± 11%; ischemic cardiomyopathy, 14) had 29 TCEA procedures attempted. In 5 patients, TCEA was abandoned because of unfavorable anatomy. In 22 patients, a mean of 1.3 ± 0.6 arteries (range, 1-3 arteries) were targeted for TCEA. After ablation, the targeted VT was no longer inducible in 18 of 22 (82%) patients. Complete heart block occurred in 5 patients, and 3 patients with advanced heart failure died within 30 days of the procedure. After the last TCEA procedure, a VT recurred in 64% of patients, and overall, 32% of patients died. Of 11 patients with prior VT storm, 9 were free of VT storm. At repeat study in 8 patients who had a recurrence, 7 had a new QRS morphology of VT originating from the same general substrate region as the prior VT. CONCLUSIONS: In patients with difficult-to-control VT in whom RFCA fails, TCEA prevents all VT recurrences in 36% and improves arrhythmia control in an additional 27%. Inadequate target vessels, collaterals, and recurrence of modified VTs limit efficacy, but TCEA continues to play an important role for difficult VTs in these high-risk patients.

Long-term follow-up in patients with presumptive Brugada syndrome treated with implanted defibrillators.

INTRODUCTION: Risk stratification for patients with suspected Brugada syndrome (BS) remains difficult. Implantation of cardioverter-defibrillators (ICDs) in high-risk patients provides continuous long-term arrhythmia protection. METHODS: Data of 33 consecutive patients undergoing ICD implantation after BS evaluation between 1995 and 2008 were reviewed. RESULTS: There were 30 (91%) men and 3 (9%) women (46.4 ± 11.7 years). Type I Brugada was noted in 18 (54.5%), type II in 12 (36.4%) patients, and ST elevation after drug challenge in 3 patients (9.1%). Three patients had prior cardiac arrest; 70% a history of syncope; and 56% ventricular arrhythmias at the electrophysiology study. During 7.9 ± 3.6 years of follow-up, 2 patients with prior arrest received appropriate ICD shocks. None of the 30 patients without prior arrest had a sustained arrhythmia detected. ICD-related adverse effects occurred in 11 (33%) patients, including inappropriate shocks in 5 (15%). Eight patients (24%) developed 11 major device-related complications including subclavian vein thrombosis (1), pericardial effusion (1), lead fracture (2), and infection (2); in 4 patients the only complication was premature battery depletion that required early ICD replacement; however, some of these complications such as lead fractures and early battery depletion may not be specific for this patient cohort and may not repeat in the future. CONCLUSION: Risk stratification for patients with BS for primary prevention remains challenging. The low risk of arrhythmic events that is exceeded by ICD-related adverse effects should inform discussions with patients who do not have a prior history of cardiac arrest.

Resetting criteria during ventricular overdrive pacing successfully differentiate orthodromic reentrant tachycardia from atrioventricular nodal reentrant tachycardia despite interobserver disagreement concerning QRS fusion.

BACKGROUND: The beginning of ventricular overdrive pacing (VOP) during supraventricular tachycardia (SVT) accurately distinguishes orthodromic reentrant tachycardia (ORT) from atrioventricular nodal reentrant tachycardia (AVNRT) even when pacing terminates tachycardia. Tachycardia resetting most often occurs during this transition zone (TZ) of QRS fusion in ORT and after this TZ in AVNRT. The end of the TZ is marked by the first beat with a stable QRS morphology but is a subjective assessment. Disagreement concerning this beat may change tachycardia diagnosis. OBJECTIVE: The purpose of this study was to assess interobserver agreement for identifying the TZ and whether disagreement affected diagnosis. METHODS: Seventy-nine consecutive patients with inducible ORT and AVNRT were included. Resetting of tachycardia was evaluated by (1) atrial timing perturbation and (2) fixed stimulation-atrial activation timing (SA). Two blinded observers identified the end of the TZ and used the two resetting criteria to establish a diagnosis. Diagnostic results were compared with standard criteria for SVT diagnosis. The diagnosis was considered correct if both electrophysiologists' TZ assessment resulted in a correct diagnosis. RESULTS: Agreement on the TZ occurred in 80% (148/186) of VOP trains. In ORT patients, tachycardia resetting occurred during the TZ and correctly diagnosed ORT based on atrial timing perturbation and fixed SA in 91% and 98% of VOP trains, respectively. In AVNRT patients, tachycardia resetting occurred after the TZ and correctly diagnosed AVNRT based on atrial timing perturbation and fixed SA in 93% and 94% of VOP trains, respectively. CONCLUSION: Resetting criteria used during the VOP TZ accurately differentiate between ORT and AVNRT despite interobserver disagreement concerning identification of the TZ.

Refractory ventricular tachycardia secondary to cardiac sarcoid: electrophysiologic characteristics, mapping, and ablation.

BACKGROUND: Cardiac sarcoidosis is a recognized cause of ventricular tachycardia (VT) and sudden death that has not been well studied. OBJECTIVES: The purpose of this study was to describe the clinical characteristics of a consecutive series of eight patients with recurrent monomorphic VT due to cardiac sarcoidosis and to define the electrophysiologic characteristics of the VT and its electrophysiologic substrate. METHODS/RESULTS: Of 98 patents with nonischemic cardiomyopathy and VT referred for ablation over a 7-year period, sarcoid was the etiology in 8%. Mean age was 42 +/- 8 years, and all but one patient had a reduced left ventricular ejection fraction (mean 34% +/- 15%). VT was the initial manifestation of sarcoid disease in 5 of 8 cases based on retrospective analysis. All patients had not responded to therapy with multiple antiarrhythmic drugs (mean 2.5 +/- 1). Cardiac biopsy initially was negative in 3 of 7 patients, and in 2 patients the diagnosis was not made until posttransplant examination of the heart. Two patients (25%) had a previous presumptive diagnosis of arrhythmogenic right ventricular dysplasia. Electrophysiologic study revealed evidence of scar-related reentry with multiple monomorphic VTs induced (4 +/- 2 VTs per patient) with both right bundle branch block and left bundle branch block QRS configurations. Areas of low-voltage scar were present in the right ventricle in all 8 of 8 patients, in the left ventricle in 5 (63%) of 8 patients, and in the epicardium in 2 patients undergoing epicardial mapping. Ablation abolished one or more VTs in 6 (75%) of 8 patients, but other VTs remained inducible in all but one patient. Postablation, some form of sustained VT recurred in 6 of 8 patients within 6 months. However, at longer follow-up (range 6 months to 7 years), 4 of 8 patients currently are free of VT with antiarrhythmic drugs and immunosuppression. Cardiac transplantation eventually was required in 5 of 8 patients because of either recurrent VT (n = 4) or heart failure (n = 1). CONCLUSION: Sarcoid is an important diagnostic consideration in scar-related VT. Sarcoid can be misdiagnosed as idiopathic or arrhythmogenic right ventricular cardiomyopathy. Arrhythmia control can be difficult, although ablation can be helpful in some patients.

Entrainment mapping for rapid distinction of left and right atrial tachycardias.

BACKGROUND: Distinguishing left from right atrial tachycardia is a critical step for guiding ablation. OBJECTIVES: The purpose of this study was to develop and validate a simple algorithm predicting the location of macroreentrant atrial tachycardia (AT) circuits from limited entrainment mapping in right atrium (RA) and coronary sinus (CS). METHODS: In 180 patients with organized reentrant AT, entrainment was performed at the high RA, proximal CS, and distal CS. The difference between the postpacing interval (PPI) and tachycardia cycle length (TCL) was calculated at each site. The location of the AT reentrant circuit was determined by mapping and ablation. An algorithm predicting AT regions was developed from 104 ATs in the first 90 patients (group I) and prospectively evaluated in a validation cohort of 106 ATs in the second 90 patients (group II). RESULTS: In group I, PPI-TCL difference <50 or >50 ms at the high RA distinguished RA from LA reentrant circuits. For RA tachycardias, PPI-TCL difference at the proximal CS distinguished common flutter from lateral RA circuits. For LA circuits, PPI-TCL difference at the proximal and distal CS distinguished perimitral reentry from reentry involving the right pulmonary veins and septum. In group II, an algorithm based on PPI-TCL difference >50 or <50 ms at the high RA, proximal CS, or distal CS had sensitivity of 94%, specificity of 88%, and predictive accuracy of 93% for predicting the successful ablation region. CONCLUSION: Limited entrainment from sites accessible from the RA can expeditiously suggest the AT location to guide more detailed mapping and potentially avoid unnecessary transseptal punctures in some patients.