Abstract Introduction Atrial fibrillation (AF) frequently accompanies heart failure with preserved ejection fraction (HFpEF). AF exacerbates HFpEF through adverse haemodynamic effects. In turn, HFpEF promotes AF through adverse left atrial remodelling. Observational data suggest sinus rhythm restoration improves outcomes in patients with AF and HFpEF. However, there are no randomised data examining the effects of rhythm control with catheter-based AF ablation on HFpEF outcomes. Purpose To compare the effects of AF ablation versus usual medical therapy on markers of HFpEF severity, including exercise haemodynamics, natriuretic peptide levels and patient symptoms. Methods Patients with symptomatic AF and HFpEF underwent exercise right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET). HFpEF diagnosis was based on left ventricular ejection fraction (LVEF) ≥50%, elevated natriuretic peptide and echocardiographic diastolic impairment. HFpEF was confirmed on exercise RHC based on peak exercise pulmonary capillary wedge pressure (PCWP) of ≥25mmHg. Patients were randomised to AF ablation versus medical therapy, with investigations repeated at 6 months. The primary outcome was change in PCWP on follow-up. Results 31 patients aged 66.1±7.5 years were randomized to AF ablation (16) versus medical therapy (15), with 51.6% female and 80.6% persistent AF. Baseline characteristics were comparable across groups. Paired analyses of ablation cohort showed significant reductions in peak PCWP (29.6±3.7 vs 25.9±4.6 mmHg, p<0.01), PCWP indexed for workload (39.0±57.9 vs 33.0±50.5 mmHg/W/kg, p<0.01), and BNP (146.2±80.5 vs 82.2±75.4 pg/mL, p=0.01); and increased resting cardiac output (4.6±0.9 vs 5.6±1.2 L/min, p=0.01), peak cardiac output (9.6±4.2 vs 10.4±3.7 L/min, p=0.02), peak (30s averaged) VO2 (1875.1±759.2 vs 2193.7±878.1 mL/min, p<0.01), peak absolute VO2 (1937.3±739.3 vs 2216.3±861.9 mL/min, p<0.01), peak (30s averaged) relative VO2 (19.4±5.9 vs 22.9±7.4 ml/kg/min) and peak workload (162.0±81.1 vs 184.4±83.4 W, p<0.01). Quality of life scores improved: AFEQT (45.3±20.9 vs 75±20.7, p<0.01) and MLHF (53±23.3 vs 17.5±22.8, p<0.01). Reversal of HFpEF by PCWP criteria occurred in 31.2% following AF ablation, and 50% among those free from arrhythmia recurrence. In the medical arm, there were no significant differences in RHC, CPET, and natriuretic peptide outcomes on follow-up versus baseline. Repeated measures mixed ANOVA testing showed significant time-randomisation interaction on peak VO2, absolute peak VO2, peak relative VO2, AFEQT/ MLHF scores, suggesting that significant improvements in these parameters were related to AF ablation. Conclusion In patients with concomitant AF and HFpEF, AF ablation improves invasive exercise haemodynamic parameters, increases exercise capacity, and enhances quality of life. Successful AF ablation may reverse the clinical syndrome of HFpEF in a subset of cases. Funding Acknowledgement Type of funding sources: None.

Methods: One hundred consecutive patients with a mean age of 54 +/- 10 years, with paroxysmal AF who underwent PVAI procedure were analyzed. Isolation of pulmonary veins was based on an electrophysiological and anatomical approach, with a nonfluoroscopic navigation mapping system to guide antral PVI. Ablation endpoint was vein isolation confirmed with a circular mapping catheter at first and subsequent procedures. Clinical, ECG, and Holter follow-up was undertaken every 3 months in the first year postablation, every 6 months thereafter, with additional prolonged monitoring if symptoms were reported. Time to arrhythmia recurrence, and representing arrhythmias, were documented.Results: Isolation of all 4 veins was successful in 97% patients with 3.9 +/- 0.3 veins isolated/patient. Follow-up after the last RF procedure was at a mean of 39 +/- 10 months (range 21-66 months). After a single procedure, sinus rhythm was maintained at long-term follow-up in 49% patients without use of antiarrhythmic drugs (AADs). After repeat procedure, sinus rhythm was maintained in 57% patients without the use of AADs, and in 82% patients including patients with AADs. A total of 18 of 100 patients had 2 procedures and 4 of 100 patients had 3 procedures for recurrent AF/AT. Most (86%) AF/AT recurrences occurred < 1 year after the first procedure. Mean time to recurrence was 6 +/- 10 months. Kaplan-Meier analysis on antiarrhythmics showed AF free rate of 87% at 1 year and 80% at 4 years. There were no major complications.Conclusion: PVAI is an effective strategy for the prevention of AF in the majority of patients with PAF. Maintenance of SR requires repeat procedure or continuation of AADs in a significant proportion of patients. After maintenance of sinus rhythm 1-year post-PVAI, a minority of patients will subsequently develop late recurrence of AF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 137-141, February 2011).

Objective: To characterize LV endocardial activation in cardiomyopathy patients with and without left bundle branch block (LBBB).

Introduction: The late AF recurrence rate in long-term follow-up of circumferential pulmonary vein isolation (CPVI) for paroxysmal AF is not well-documented.

Objective: To compare the electrophysiologic substrate in non-ischemic dilated cardiomyopathy (DCM) with and without clinical sustained monomorphic ventricular tachycardia (SMVT).

Background: Incessant focal atrial tachycardia (AT) may be complicated by LV dysfunction. The aim was to characterise the incidence, ECG and EP features of incessant focal AT and identify predictors of tachycardia mediated cardiomyopathy (TCM).

Background: There is increased interest in the substrate-modification approach to catheter ablation for mappable and unmappable scar-related ventricular tachycardia (VT).

The goal of this study was to characterize the electrocardiographic and electrophysiologic features and frequency of focal atrial tachycardia (AT) originating from the coronary sinus ostium (CS). The ostium of the coronary sinus has been described as a site of origin of AT, but detailed characterization of these tachycardias is limited. Thirteen patients (6.7%) of 193 undergoing radiofrequency ablation (RFA) for focal AT are reported. Enclocardial activation maps (EAM) were recorded from catheters at the CS (10 pole), crista terminalis (20 pole), and His positions. The P waves were classified negative, positive, isoelectric, or biphasic. The mean age was 41 +/- 6 years, seven female patients, with symptoms for 8 +/- 3 years. Tachyeardia was induced by programmed extra-stimuli in eight patients, was spontaneous in three patients, and in response to isoproterenol in two patients. These foci had a characteristic P-wave morphology. At the CS ostium, the P-wave was deeply negative in all inferior leads, negative or isoelectric becoming positive in lead V-1, then progressively negative across the precordium. Lead aVL was positive in all patients. Earliest EAM activity occurred at the proximal CS at 20 +/- 3 ms ahead of P-wave. Mean activation time at the successful RFA site = -36 +/- 8 ms; RFA was acutely successful in 11 of 13 patients. Long-term success was achieved in 11 of 11 over a median follow-up of 25 +/- 4 months. The CS ostium is an uncommon site of origin for focal AT (6.7%). It can be suspected as a potential anatomic site of AT origin from the characteristic P-wave and activation timing. Long-term success was achieved with focal ablation in the majority of patients. (c) 2005 by the American College of Cardiology Foundation.

BACKGROUND Few descriptions of right atrial macroreentrant atrial tachycardia involving regions of spontaneous "scar" have been reported.OBJECTIVES We describe the electrocardiographic, electrophysiologic, and electroanatomic characteristics of an unusual RA macroreentrant atrial tachycardia in eight patients with spontaneous RA scarring.METHODS Eight of 286 patients with macroreentrant atrial tachycardia treated with radiofrequency ablation had RA spontaneous scarring and underwent conventional electrophysiologic studies and electroanatomic mapping.RESULTS Eight patients (age 53 +/- 12 years) had symptoms for 58 62 months and had not responded to 2.5 +/- 0.8 antiarrhythmic drugs and 1.0 +/- 0.9 DC cardioversions. All patients had overall normal systolic function, and five had mild atrial enlargement. Scarring was present in the posterolateral wall extending from the crista terminalis toward the tricuspid annulus. The proportion of RA classified as scar was 31% +/- 14% (range 11%-46%). Stable circuits were around scar in seven patients, through a "channel" within the scar in four, and typical cavotricuspid isthmus-dependent flutter in five. Radiofrequency ablation sites included the cavotricuspid isthmus; between the inferior vena cava, superior vena cava, or crista terminalis and scar; or a channel in the scar. ECG morphology of the RA free wall tachycardias varied, depending upon whether cavotricuspid isthmus block was present. Radiofrequency ablation of all inducible circuits was successful in six patients and of all clinical circuits in seven. At follow-up of 20 +/- 13 months, six patients are free from macroreentrant atrial tachycardia, one has infrequent nonsustained macroreentrant atrial tachycardia, and one is controlled with previously ineffective medication. Five had sinus node dysfunction requiring permanent pacemaker implant.CONCLUSIONS Extensive spontaneous scarring of the RA is an unusual cause of macroreentrant atrial tachycardias, both cavotricuspid isthmus dependent and independent in the same patient. Radiofrequency ablation is an effective treatment. Sinus node dysfunction requiring permanent pacemaker is common. The cause is unknown.

This study reports that patients with large body mass indexes (BMIs) and long-duration atrial fibrillation (AF) have greater defibrillation thresholds than patients with normal BMIs and AF of short duration. BMI is an independent predictor of defibrillation thresholds in patients with longer duration AF in whom external cardioversion has failed.

Introduction: Focal atrial fibrillation (AF) may initiate with an irregular rapid burst of atrial ectopic (AE) activity from a pulmonary vein (PV) focus, but how AF is maintained it is not known. The crista terminalis (CT) is an important line of block in atrial flutter (AFL), but its role in AF has not been determined. The aim of this study was to examine the conduction properties of the CT during onset of AF. Methods and Results: In 10 patients (mean age 38 ± 8 years), we analyzed conduction across the CT during onset of focal AF from an arrhythmogenic PV and during pacing from the same PV at cycle lengths of 700 and 300 ms. A 20‐pole catheter was positioned on the CT using intracardiac echocardiography. In 10 control patients with no history of AF, we analyzed conduction across the CT during pacing from the distal coronary sinus at 700 and 300 ms. In all 10 AF patients, AF was initiated with 1 to 9 AE beats (median 5) from a PV. During sinus rhythm, there were no split components (SC) recorded on the CT. During PV AE activity, discrete SC were recorded on the CT in all patients over 6.3 ± 0.9 bipoles (3.7 ± 0.3 cm). Maximal splitting of SC was 66 ± 31 ms (37–139). There was an inverse relationship between AE coupling intervals and the degree of splitting between SC in all patients. Degeneration to AF was preceded by progressive decrement across the CT. SC were recorded during PV pacing at 700 and 300 ms (maximal distance between SC of 24 ± 3 ms and 43 ± 5 ms, respectively, P < 0.001). Maximum SC at CT in controls was 13 ± 8 ms at 700 ms (P = 0.06 vs AF patients) and 16 ± 9 ms at 300 ms (P < 0.01 vs AF patients). Conclusion: (1) These observations provide evidence of anisotropic, decremental conduction across the CT during onset of focal AF and during pacing from the same PV. A line of functional conduction block develops along this anatomic structure (CT). Whether this line of block acts as an initiator of AF or simply contributes passively to nonuniform fibrillatory conduction is unknown. (2) In some patients with focal AF, development of conduction block along the CT may provide a substrate for typical AFL.

Background— Experimental and clinical studies have demonstrated diffuse atrial remodeling in congestive heart failure (CHF). We hypothesized that patients with CHF would demonstrate derangement of sinus node function. Methods and Results— Eighteen patients with symptomatic CHF (left ventricular ejection fraction, 26±5%) and 18 age-matched control subjects were studied. Under autonomic blockade, the following were evaluated: intrinsic sinus cycle length, corrected sinus node recovery time (CSNRT), sinoatrial conduction time, number and duration of fractionated electograms or double potentials along the crista terminalis, and location of the earliest sinus activity. Electroanatomic mapping was performed to evaluate the location and nature of the sinus node complex, to characterize sinoatrial propagation, and to evaluate conduction abnormalities and voltage amplitude along the crista terminalis. Patients with CHF demonstrated the following findings compared with age-matched control subjects: prolongation of the intrinsic sinus cycle length ( P =0.005), prolongation of CSNRT ( P <0.0001), caudal localization of sinus activity both during sinus rhythm ( P =0.03) and after pacing ( P =0.002), prolongation of sinoatrial conduction time ( P =0.02), greater number ( P <0.0001) and duration ( P <0.0001) of fractionated electrograms or double potentials along the crista terminalis, loss of voltage amplitude along the crista terminalis ( P =0.02), and abnormal and circuitous propagation of the sinus impulse. Conclusions— This study demonstrates that patients with CHF have significant sinus node remodeling characterized by anatomic and structural changes along the crista terminalis with a reduction in functional sinus node reserve. This finding may have implications for the development of clinical bradycardia in CHF and for the use of negatively chronotropic agents and pacing in this condition.

Since the first reports of curative catheter ablation for atrial fibrillation (AF) appeared now almost a decade ago, the procedure has undergone numerous modifications and refinements that have resulted in increased cure rates. Coincident with this evolution has been the gradual expansion in the patient population considered suitable for curative ablation. While early series restricted patient inclusion to those with paroxysmal AF and no structural heart disease, later series have begun to include persistent and even chronic AF patients and, more recently, those with significant structural heart disease. Several recent studies have analyzed outcome after AF catheter ablation according to the presence or absence of structural heart disease. In a preliminary report, Wilber et al 1 Morton J.B Lipman E.W Lin A.C Tierney S Burke M.C Cai J.C Santucci P.A Wilber D.J Factors predictive of a late recurrence of atrial fibrillation after segmental pulmonary vein isolation. 2004 Annual Scientific Sessions. J Am Coll Cardiol. 2004; 43 (abstr): 133A Abstract Full Text PDF PubMed Google Scholar identified a reduced left ventricular ejection fraction (<50%) as 1 independent predictor of AF recurrence after pulmonary vein (PV) isolation. Others have identified left atrial enlargement, but not structural heart disease, as predictors of AF recurrence. 2 Pappone C Oreto G Rosanio S Vicedomini G Tocchi M Gugliotta F Salvati A Dicandia C Calabro M.P Mazzone P Ficarra E Di Gioia C Gulletta S Nardi S Santinelli V Benussi S Alfieri O Atrial electroanatomic remodeling after circumferential radiofrequency pulmonary vein ablation efficacy of an anatomic approach in a large cohort of patients with atrial fibrillation. Circulation. 2001; 104: 2539-2544 Crossref PubMed Scopus (801) Google Scholar , 3 Oral H Scharf C Chugh A Hall B Cheung P Good E Veerareddy S Pelosi Jr, F Morady F Catheter ablation for paroxysmal atrial fibrillation segmental pulmonary vein ostial ablation versus left atrial ablation. Circulation. 2003; 108: 2355-2360 Crossref PubMed Scopus (790) Google Scholar

Background— The normal sinus pacemaker complex is an extensive structure within the right atrium. We hypothesized that patients with sinus node disease (SND) would have evidence of diffuse atrial abnormalities. Methods and Results— Sixteen patients with symptomatic SND and 16 age-matched controls were studied. The following were evaluated: effective refractory periods (ERPs) from the high and low lateral right atrium (RA), high septal RA, and distal coronary sinus (CS); conduction time along the CS and lateral RA; P-wave duration; and conduction at the crista terminalis. Electroanatomic mapping was performed to define the sinus node complex and determine regional conduction velocity, double potentials, fractionated electrograms, regional voltage, and areas of electrical silence. Patients with SND demonstrated significant increase in atrial ERP at all right atrial sites, increased atrial conduction time along the lateral RA and CS, prolongation of the P-wave duration, and greater number and duration of double potentials along the crista terminalis. Electroanatomic mapping demonstrated the sinus node complex in SND to be more often unicentric, localized to the low crista terminalis at the site of the largest residual voltage amplitude. There was significant regional conduction slowing with double potentials and fractionation associated with areas of low voltage and electrical silence (or scar). Conclusions— SND is associated with diffuse atrial remodeling characterized by structural change, conduction abnormalities, and increased right atrial refractoriness. There was a change in the nature of sinus pacemaker activity with loss of the normal multicentric pattern of activation, caudal shift of the pacemaker complex, and abnormal and circuitous conduction around lines of conduction block.

Background— Atrial fibrillation (AF) frequently complicates congestive heart failure (CHF). However, the electrophysiological substrate for AF in humans with CHF remains unknown. We evaluated the electrophysiological and electroanatomic characteristics of the atria in patients with CHF. Methods and Results— Twenty-one patients (aged 53.7±13.6 years) with symptomatic CHF (left ventricular ejection fraction 25.5±6.0%) and 21 age-matched controls were studied. The following were evaluated: effective refractory periods (ERPs) from the high and low lateral right atrium (LRA), high septal right atrium, and distal coronary sinus (CS); conduction time along the CS and LRA; corrected sinus node recovery times; P-wave duration; and conduction at the crista terminalis. In a subset, electroanatomic mapping was performed to determine atrial activation, regional conduction velocity, double potentials, fractionated electrograms, regional voltage, and areas of electrical silence. Patients with CHF demonstrated an increase in atrial ERP with no change in the heterogeneity of refractoriness, an increase of atrial conduction time along the LRA and the CS, prolongation of the P-wave duration and corrected sinus node recovery times, and greater number and duration of double potentials along the crista terminalis. Electroanatomic mapping demonstrated regional conduction slowing with a greater number of electrograms with fractionation or double potentials, associated with areas of low voltage and electrical silence (scar). Patients with CHF demonstrated an increased propensity for AF with single extrastimuli, and induced AF was more often sustained. Conclusions— Atrial remodeling due to CHF is characterized by structural changes, abnormalities of conduction, sinus node dysfunction, and increased refractoriness. These abnormalities may be responsible in part for the increased propensity for AF in CHF.

Background— Atrial mechanical “stunning” develops after cardioversion of atrial fibrillation (AF) and is implicated in the genesis of thromboembolic complications. However, the mechanisms responsible for this phenomenon are poorly understood. Whether atrial mechanical dysfunction caused by AF can be reversed by pacing at increased rates or by pharmacological agents is unknown. Methods and Results— Twenty-six patients with AF undergoing cardioversion were dichotomized prospectively on the basis of the duration of arrhythmia as short-duration (1 to 6 months) or long-duration (≥3 years) AF. Left atrial appendage emptying velocities (LAAEVs) and spontaneous echocardiographic contrast (LASEC) were assessed by transesophageal echocardiography during AF, after reversion to sinus rhythm, during atrial pacing at cycle lengths of 750 to 250 ms, after a postpacing pause, and with isoproterenol. In patients with short-duration AF, LAAEV decreased (42.0±2.7 to 18.5±2.0 cm/s; P <0.0001) and LASEC increased (0.9±0.3 to 2.2±0.3; P <0.01) with termination of AF; pacing increased LAAEV (48.3±4.1 cm/s; P <0.0001) and decreased LASEC (1.5±0.3; P <0.01); isoproterenol increased LAAEV (73.3±7.8 cm/s; P <0.0001) and decreased LASEC (0.3±0.2; P <0.01); and the postpacing pause increased LAAEV (68.3±3.8 cm/s; P <0.0001). In contrast, patients with long-duration AF demonstrated a significantly attenuated response of atrial mechanical function at each time point. With termination of AF, LAAEV decreased (19.1±2.6 to 8.2±1.0 cm/s; P =0.003) and LASEC increased (2.0±0.2 to 3.3±0.2; P <0.01); pacing increased LAAEV (18.4±2.7 cm/s; P <0.0001) and decreased LASEC (2.3±0.2; P <0.01); isoproterenol increased LAAEV (26.1±3.9 cm/s; P =NS to equivalent atrial rate) and decreased LASEC (1.0±0.3; P <0.01); and the postpacing pause increased LAAEV (27.2±2.4 cm/s; P =0.007). Conclusions— Atrial pacing at increased rates and isoproterenol can reverse atrial mechanical stunning associated with short-duration AF. In contrast, long-duration AF is associated with an attenuated response to these maneuvers. These findings suggest a functional contractile apparatus in the mechanically remodeled atrium caused by AF; however, with longer durations of AF, additional factors may determine atrial mechanical function.

Background— Adults with an atrial septal defect (ASD) frequently develop late atrial arrhythmias. We sought to characterize the pattern and persistence of atrial electrical remodeling caused by chronic right atrial (RA) stretch in this group. Methods and Results— Thirteen ASD patients without atrial arrhythmia (42±10 years old; RA volume, 65±16 mL) and 17 normal control subjects (44±11 years old; RA volume, 38±8 mL) had electrophysiological study to measure (1) atrial effective refractory period (AERP) from the low lateral/high lateral/high septal RA and distal coronary sinus (CS), (2) dispersion of AERP, (3) lateral-RA and CS conduction time during constant pacing, (4) conduction delay across the crista terminalis measuring the number of crista catheter bipoles (0–10) recording discrete double potentials during pacing, (5) corrected sinus node recovery time, and (6) P-wave duration. After ASD closure (8.3±5.6 months), follow-up echo studies (n=12) and electrophysiological study (n=4) were performed. The low-lateral AERP, P-wave duration, sinus node recovery time, and extent of conduction delay across the crista terminalis were significantly greater in ASD patients. No differences were found for other measured electrophysiological study parameters. At follow-up, there was incomplete resolution of RA volume (47±12 mL; P <0.01 versus before surgery), a trend toward shortening of the AERP at the lateral RA and an increase at the distal CS and high septal RA, but persisting extensive, widely split crista double potentials. Conclusions— Chronic RA stretch because of ASD causes electrical remodeling with modest increases in RA ERP, conduction delay at the crista terminalis, and sinus node dysfunction. Conduction delay at the crista terminalis persists beyond ASD closure and may contribute to the long-term atrial arrhythmia substrate in this condition.

Introduction: Cavotricuspid isthmus (CTI) topography includes ridges, pouches, recesses, and trabeculations. These features may limit the success of radiofrequency ablation (RFA) of typical atrial flutter (AFL). The aim of this study was to assess the utility of phased‐array intracardiac echocardiography (ICE) for imaging the CTI and monitoring RFA of AFL. Methods and Results: Fifteen patients (mean age 64 ± 9 years) underwent ICE assessment (imaging frequency 7.5–10 MHz) before and after RFA of AFL. The ICE catheter was positioned at the inferior vena cava‐right atrial junction and the following parameters were measured: (1) CTI length from the tricuspid valve to the eustachian ridge; (2) extent of CTI pouching; and (3) thickness pre/post RFA of the anterior, mid, and posterior CTI. CTI length was 35 ± 6 mm at end‐ventricular systole but shorter (30 ± 6 mm) and more pouched at end‐ventricular diastole (P = 0.02) . A pouch or recess was seen in 11 of 15 patients (mean depth6 ± 2 mm). The septal CTI was more pouched than the lateral CTI, but the latter had more prominent trabeculations. Trabeculations were seen in 10 of 15 patients, and at these locations the CTI was4.6 ± 1 mmthick. Anterior, mid, and posterior CTI thickness pre‐RFA was4.1 ± 0.8, 3.3 ± 0.5, and2.7 ± 0.9 mm, respectively (P < 0.001by analysis of variance). ICE guided RFA away from unfavorable CTI features (recesses/thick trabeculations). RFA applications created discrete CTI lesions that coalesced, forming diffuse CTI swelling. Post‐RFA thickness was as follows: anterior4.8 ± 0.8 mm (P = NSvs pre); mid3.8 ± 0.8 mm (P = 0.05 vs pre); and posterior3.8 ± 0.8 mm (P = 0.02 vs pre). Conclusion: Phased‐array ICE permits novel real‐time CTI imaging with excellent endocardial resolution and may facilitate RFA of AFL. (J Cardiovasc Electrophysiol, Vol. 14, pp. 591‐597, June 2003)