Ralph J. Verdino

Endocardial unipolar voltage mapping to detect epicardial ventricular tachycardia substrate in patients with nonischemic left ventricular cardiomyopathy

Background—Patients with nonischemic left ventricular cardiomyopathy (LVCM) and ventricular tachycardia (VT) have complex 3-dimensional substrate with variable involvement of the endocardium (ENDO) and epicardium (EPI). The purpose of this study was to determine whether ENDO unipolar (UNI) mapping with a larger electric field of view could identify EPI low bipolar (BIP) voltage regions in patients with LVCM undergoing VT ablation. Methods and Results—The reference value for normal ENDO unipolar voltage was determined from 6 patients without structural heart disease. Consecutive patients undergoing VT ablation over an 8-year period with detailed (>100 points) LV ENDO and EPI mapping and normal LV ENDO BIP voltage were identified. From this cohort, we compared patients with structurally normal hearts and normal EPI BIP voltage (EPI−, group 1) with patients with LVCM and low LV EPI BIP voltage regions present (EPI+, group 2). Confluent regions of ENDO UNI and EPI BIP low voltage (>2 cm2) were measured. The normal signal amplitude was >8.27 mV for LV ENDO UNI electrograms. Detailed LV ENDO-EPI maps in 5 EPI− patients were compared with 11 EPI+ patients. Confluent ENDO UNI low-voltage regions were seen in 9 of 11 (82%) of the EPI+ (group 2) patients compared with none of 5 EPI− (group 1) patients (P<0.001). In all 9 patients with ENDO UNI low voltage, the ENDO UNI low-voltage regions were directly opposite to an area of EPI BIP low voltage (61% ENDO UNI-EPI BIP low-voltage area overlap). Conclusions—EPI arrhythmia substrate can be reliably identified in most patients with LVCM using ENDO UNI voltage mapping in the absence of ENDO BIP abnormalities.

Long-Term Outcome After Successful Catheter Ablation of Atrial Fibrillation

Background—Pulmonary vein isolation (PVI) is increasingly used for treatment of atrial fibrillation (AF), but few reports exist regarding long-term success. We determined 5-year outcomes of PVI among patients with freedom from AF off antiarrhythmic drugs (AAD) for 1 year after PVI. Methods and Results—Consecutive patients with paroxysmal or persistent AF who underwent PVI at the University of Pennsylvania from 2000 to 2003 and were free from AF 1 year after ablation were included. Proximal isolation of PVs and non-PV triggers of AF was performed. Long-term ablation success, defined as freedom from AF off AAD after a single ablation procedure, was determined. All patients had transtelephonic monitoring at 3 to 6 months and 12 months and at least yearly contact thereafter. One hundred twenty-three patients were free of AF without AAD at 1 year. AF freedom off AAD was 85% at 3 years and 71% at 5 years, with an approximate 7% per year late recurrence rate after the first year. Patients with recurrent AF ≥5 years after index PVI were older, had larger left atrial size, more AF triggers and more likely had persistent AF. In multivariate analysis, persistent AF (odds ratio, 2.8; 95% confidence interval, 1.4 to 5.7, P=0.005) and age (odds ratio, 1.1; 95% confidence interval, 1.0 to 1.1, P=0.036) independently predicted long-term AF recurrence. Conclusions—Among patients with paroxysmal or persistent AF and AF freedom 1 year after segmental PVI, the majority (71%) remained free of AF for up to 5 years, with an approximate late recurrence rate of 7% per year. Continued vigilance for recurrent AF after PV isolation is warranted, particularly in patients with persistent AF.

Atrial Fibrillation After Radiofrequency Ablation of Type I Atrial Flutter Time to Onset, Determinants, and Clinical Course

BACKGROUND The occurrence of atrial fibrillation after ablation of type I atrial flutter remains an important clinical problem. To gain further insight into the pathogenesis and significance of postablation atrial fibrillation, we examined the time to onset, determinants, and clinical course of atrial fibrillation after ablation of type I flutter in a large patient cohort. METHODS AND RESULTS Of 110 consecutive patients with ablation of type I atrial flutter, atrial fibrillation was documented in 28 (25%) during a mean follow-up of 20.1+/-9.2 months (cumulative probability of 12% at 1 month, 23% at 1 year, and 30% at 2 years). Among 17 clinical and procedural variables, only a history of spontaneous atrial fibrillation (relative risk 3.9, 95% confidence intervals 1.8 to 8.8, P=0.001) and left ventricular ejection fraction <50% (relative risk 3.8, 95% confidence intervals 1.7 to 8.5, P=0.001) were significant and independent predictors of subsequent atrial fibrillation. The presence of both these characteristics identified a high-risk group with a 74% occurrence of atrial fibrillation. Patients with only 1 of these characteristics were at intermediate risk (20%), and those with neither characteristic were at lowest risk (10%). The determinants and clinical course of atrial fibrillation did not differ between an early (< or = 1 month) compared with a later onset. Atrial fibrillation was persistent and recurrent, requiring long-term therapy in 18 patients, including 12 of 19 (63%) with prior atrial fibrillation and left ventricular dysfunction. CONCLUSIONS Atrial fibrillation after type I flutter ablation is primarily determined by the presence of a preexisting structural and electrophysiological substrate. These data should be considered in planning postablation management. The persistent risk of atrial fibrillation in this population also suggests a potentially important role for atrial fibrillation as a trigger rather than a consequence of type I atrial flutter.

Long‐Term Clinical Efficacy and Risk of Catheter Ablation for Atrial Fibrillation in the Elderly

Introduction: The number of elderly patients with atrial fibrillation (AF) is increasing rapidly, and the safety and efficacy of catheter ablation in this demographic group has not been established.

Atypical Atrial Flutter Originating in the Right Atrial Free Wall

BACKGROUND Data from experimental models of atrial flutter indicate that macro-reentrant circuits may be confined by anatomic and functional barriers remote from the tricuspid annulus-eustachian ridge atrial isthmus. Data characterizing the various forms of atypical atrial flutter in humans are limited. METHODS AND RESULTS In 6 of 160 consecutive patients referred for ablation of counterclockwise and/or clockwise typical atrial flutter, an additional atypical atrial flutter was mapped to the right atrial free wall. Five patients had no prior cardiac surgery. Incisional atrial tachycardia was excluded in the remaining patient. High-density electroanatomic maps of the reentrant circuit were obtained in 3 patients. Radiofrequency energy application from a discrete midlateral right atrial central line of conduction block to the inferior vena cava terminated and prevented the reinduction of atypical atrial flutter in each patient. Atrial flutter has not recurred in any patient (follow-up, 18+/-17 months; range, 3 to 40 months). CONCLUSIONS Atrial flutter can arise in the right atrial free wall. This form of atypical atrial flutter could account for spontaneous or inducible atrial flutter observed in patients referred for ablation and is eliminated with linear ablation directed at the inferolateral right atrium.

Incidence and Predictors of Very Late Recurrence of Atrial Fibrillation After Ablation

Introduction: Radiofrequency catheter ablation can effectively treat patients with refractory atrial fibrillation (AF). Very late AF recurrence (≥12 months post‐ablation) is uncommon and may represent a unique patient cohort.

Changes in Heart Rate and Heart Rate Variability Before Ambulatory Ischemic Events

Abstract OBJECTIVES The aim of this study was to determine the time course of autonomic nervous system activity preceding ambulatory ischemic events. BACKGROUND Vagal withdrawal can produce myocardial ischemia and may be involved in the genesis of ambulatory ischemic events. We analyzed trajectories of heart rate variability (HRV) 1 h before and after ischemic events, and we examined the role of exercise and mental stress in preischemic autonomic changes. METHODS Male patients with stable coronary artery disease (n = 19; 62.1 ± 9.3 years) underwent 48-h ambulatory electrocardiographic monitoring. Frequency domain HRV measures were assessed for 60 min before and after each of 68 ischemic events and during nonischemic heart rate-matched control periods. RESULTS High-frequency HRV decreased from −60, −20 to −10 min before ischemic events (4.8 ± 1.3; 4.6 ± 1.3; 4.4 ± 1.2 ln [ms2], respectively; p = 0.04) and further from −4, −2 min, until ischemia (4.4 ± 1.3; 4.1 ± 1.3; 3.7 ± 1.2 ln [ms2]; p’s CONCLUSIONS Autonomic changes consistent with vagal withdrawal can act as a precipitating factor for daily life ischemia, particularly in episodes triggered by mental activities.

Single procedure efficacy of isolating all versus arrhythmogenic pulmonary veins on long-term control of atrial fibrillation: A prospective randomized study

BACKGROUND Current atrial fibrillation (AF) ablation involves isolation of all pulmonary veins (PVs) with or without additional linear lesions. However, whether such extensive ablation is necessary is unclear. OBJECTIVE The purpose of this study was to assess the efficacy of different ablation strategies on long-term AF control. METHODS We prospectively randomized patients to undergo isolation of all versus arrhythmogenic PVs (identified by standardized stimulation protocol). PV isolation was guided by circular mapping catheter. The endpoint was entry/exit block persisting for > or = 20 minutes. Patients were evaluated at three clinic visits (at 6 weeks, 6 months, and 1 year) and multiple transtelephonic monitoring periods. Antiarrhythmic drugs were discontinued at 6 weeks. Primary study endpoint was long-term AF control (freedom or >90% reduction in AF burden off or on previously ineffective antiarrhythmic drugs at 1 year after a single ablation procedure). RESULTS Over a 20-month period, 105 patients (76 men and 29 women, age 57 +/- 9 years; paroxysmal AF = 77) were randomized, and 103 patients completed 1-year follow-up (51 patients in all-PV arm, 52 patients in arrhythmogenic PV arm). The primary endpoint was achieved in 75 (73%) patients and was similar in patients randomized to all-PV arm versus arrhythmogenic PV arm [38 (75%) patients vs 37 (71%) patients, respectively; odds ratio 1.18, 95% confidence interval 0.50, 2.83, P = .70]. Secondary study endpoints, including freedom from AF off antiarrhythmic drugs, total procedure/fluoroscopy times, and occurrence of serious adverse events, were not different between the two groups. CONCLUSION In a randomized comparison, isolation of arrhythmogenic veins was as efficacious as empiric isolation of all veins in achieving long-term AF control.

Antiarrhythmics After Ablation of Atrial Fibrillation (5A Study): Six-Month Follow-Up Study

Background—We previously demonstrated that treatment with antiarrhythmic drugs (AADs) during the first 6 weeks after atrial fibrillation (AF) ablation reduces the incidence of clinically significant atrial arrhythmias and need for cardioversion or hospitalization for arrhythmia management. Whether early rhythm suppression decreases longer-term arrhythmia recurrence is unknown. We now report the 6-month follow-up data from this study. Methods and Results—The Antiarrhythmics After Ablation of Atrial Fibrillation study prospectively randomized patients with paroxysmal AF undergoing ablation to either receive (AAD group) or not receive (no-AAD group) AAD treatment for the first 6 weeks after ablation; all patients received atrioventricular nodal blockers. Physicians were encouraged to stop the AADs after the 6-week treatment period. All patients underwent 4 weeks of transtelephonic monitoring to document asymptomatic AF and an evaluation at 6 weeks and 6 months. A total of 110 patients (71% men) aged 55±9 years were randomized, with 53 to AAD and 57 to no AAD. At 6 months, there was no difference in freedom from AF between the early AAD and no-AAD groups (38/53 [72%] versus 39/57 [68%]; P=0.84). Lack of early AF recurrence during the initial 6-week period was the only independent predictor of 6-month freedom from AF (64/76 [84%] without early recurrence versus 13/34 [38%] with early recurrence; P=0.0001). Conclusions—Although short-term use of AADs after AF ablation decreases early recurrence of atrial arrhythmias, early use of AADs does not prevent arrhythmia recurrence at 6 months. Early AF recurrence on or off AADs during the initial 6-week blanking period is a strong independent predictor of long-term AF recurrence. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00408200.

Atrioventricular Nodal Reentrant Tachycardia in Patients Referred for Atrial Fibrillation Ablation Response to Ablation That Incorporates Slow-Pathway Modification

Background— Although the most common sites of atrial ectopy that trigger atrial fibrillation (AF) are in or around the pulmonary veins (PVs), atrioventricular nodal reentrant tachycardia (AVNRT) can also cause or coexist with AF. We sought to characterize patients with AF and AVNRT and assess clinical outcomes after ablation. Methods and Results— To determine the prevalence of concomitant AVNRT and AF, 629 consecutive patients referred for catheter ablation between November 1998 and March 2005 were studied. Electrophysiological studies with programmed stimulation during isoproterenol infusion identified atrial ectopy that initiated AF and the presence of inducible AVNRT. AF ablation consisted of proximal isolation of PVs and elimination of any non-PV trigger of AF, including AVNRT. There were 27 patients (4.3%) who had inducible AVNRT at the time of AF ablation. Of these, 13 underwent AVNRT ablation without PV isolation. Compared with the rest of the cohort, patients with AVNRT and AF were younger at the time of symptom onset (age 36.8±13.8 versus 48.2±11.7 years; P<0.01). Freedom from AF with or without previously ineffective antiarrhythmic medication was similar in both groups (96.3% versus 90.7%; mean follow-up 21.4±9.4 months); however, patients with AVNRT targeted for ablation were more likely to be AF free while not taking any antiarrhythmic medication after a single procedure during the follow-up period (87.5% versus 54.7%; P<0.01) and had fewer complications (0% versus 2.5%; P=0.30). Twelve of the 13 patients who underwent slow-pathway ablation without left atrial ablation remained AF free without the need for antiarrhythmic medication after a single procedure. Conclusions— AVNRT is an uncommon AF trigger seen more frequently in younger patients. Ablation of AVNRT in patients with AF was associated with improved outcomes compared with those with other triggers of AF.