Absence Of Antiarrhythmic Drugs Research Articles

Catheter ablation for atrial fibrillation in adult congenital heart disease: an international registry study

Abstract Background Life expectancies for patients with congenital heart disease (CHD) have dramatically increased in recent years, accompanied by a rise in atrial fibrillation (AF) prevalence. Data on AF ablation strategy and outcomes are limited in CHD. Purpose We aimed to investigate the characteristics of CHD patients presenting for AF ablation and their outcomes. Methods A multicenter, retrospective analysis was performed of CHD patients undergoing AF ablation between 2004 and 2020 at 13 participating centers. The severity of CHD was classified using the 2014 PACES/HRS guidelines. Clinical data were collected including ablation strategy and follow up. One-year procedural success was defined as freedom from AF in the absence of antiarrhythmic drugs (AADs, complete) or including previously failed AADs (partial). Results Of 240 patients, 127 (53.4%) had persistent AF, 62.5% were male, and mean age was 55.2±0.9 years. CHD complexity categories included 147 (61.3%) simple, 69 (28.8%) intermediate and 25 (10.4%) severe. The most common CHD type was atrial septal defect (n=78). More complex CHD conditions included transposition of the great arteries (n=14), anomalous pulmonary veins (n=13), tetralogy of Fallot (n=8), cor triatriatum (n=7), single ventricle physiology (n=2), among others. The majority (71.3%) of patients had AF despite at least one AAD. 46 patients (22.1%) had a reduced systemic ventricular ejection fraction <50%, and the mean left atrial diameter was 44.1±0.7 mm. PV isolation (PVI) was performed in 227 patients (94.6%); additional ablation strategies included left atrial linear ablations (25.4%), CFAE (19.2%), and cavotricuspid isthmus ablation (40.8). One-year complete and partial success rates were 45.0% and 20.5%, respectively, with no significant difference in the rate of complete success between complexity groups. Overall, 38 patients (15.8%) required more than one ablation procedure. There were 3 (1.3%) major and 13 (5.4%) minor procedural complications. Conclusion AF ablation in this complex population was safe and resulted in AF control in the majority of patients. Future work should address the most appropriate ablation targets in the challenging population. Funding Acknowledgement Type of funding sources: None.

Catheter Ablation for Atrial Fibrillation in Adult Congenital Heart Disease: An International Multicenter Registry Study.

Data on atrial fibrillation (AF) ablation and outcomes are limited in patients with congenital heart disease (CHD). We aimed to investigate the characteristics of patients with CHD presenting for AF ablation and their outcomes. A multicenter, retrospective analysis was performed of patients with CHD undergoing AF ablation between 2004 and 2020 at 13 participating centers. The severity of CHD was classified using 2014 Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society guidelines. Clinical data were collected. One-year complete procedural success was defined as freedom from atrial tachycardia or AF in the absence of antiarrhythmic drugs or including previously failed antiarrhythmic drugs (partial success). Of 240 patients, 127 (53.4%) had persistent AF, 62.5% were male, and mean age was 55.2±13.3 years. CHD complexity categories included 147 (61.3%) simple, 68 (28.3%) intermediate, and 25 (10.4%) severe. The most common CHD type was atrial septal defect (n=78). More complex CHD conditions included transposition of the great arteries (n=14), anomalous pulmonary veins (n=13), tetralogy of Fallot (n=8), cor triatriatum (n=7), single ventricle physiology (n=2), among others. The majority (71.3%) of patients had trialed at least one antiarrhythmic drug. Forty-six patients (22.1%) had reduced systemic ventricular ejection fraction <50%, and mean left atrial diameter was 44.1±8.2 mm. Pulmonary vein isolation was performed in 227 patients (94.6%); additional ablation included left atrial linear ablations (40%), complex fractionated atrial electrogram (19.2%), and cavotricuspid isthmus ablation (40.8%). One-year complete and partial success rates were 45.0% and 20.5%, respectively, with no significant difference in the rate of complete success between complexity groups. Overall, 38 patients (15.8%) required more than one ablation procedure. There were 3 (1.3%) major and 13 (5.4%) minor procedural complications. AF ablation in CHD was safe and resulted in AF control in a majority of patients, regardless of complexity. Future work should address the most appropriate ablation targets in this challenging population.

Abstract 13597: Association Between Antiarrhythmic Drug Therapy Prescription in the Blanking Period and Recurrent Atrial Arrhythmias After First-time Catheter Ablation for Atrial Fibrillation

Introduction: Antiarrhythmic drugs (AAD) are often prescribed in the blanking period (BP) after catheter ablation of atrial fibrillation (AF) to reduce risk of early recurrence (ER) and late recurrence (LR). There are limited data on which AAD to use during the BP. Hypothesis: We hypothesize that specific AADs may be associated with reduced risk of ER and/or LR after ablation. Methods: A total of 478 consecutive patients (mean age 64.2 years, 67.2% male) undergoing first-time pulmonary vein isolation (PVI) ablation at a single institution were included. Outcomes of interest were: freedom from ER, freedom from LR, initial discontinuation of AAD less than 90 days after ablation, and freedom from second ablation. ER was defined as AF, atrial flutter (AFL), or atrial tachycardia (AT) &gt; 30 seconds within the BP. LR was defined as AF/AFL/AT &gt; 30 seconds occurring after the BP. Results: Of 478 patients, 14.9% (n = 71) were on no AAD, 26.4% (n = 126) were on propafenone/flecainide, 34.5% (n = 165) were on sotalol/dofetilide, 10.7% (n = 51) were on dronedarone, and 13.6% (n = 65) were on amiodarone. Patients on amiodarone were older, had higher BMI, and were more likely to have persistent AF, hypertension, diabetes, heart failure, and coronary artery disease. In unadjusted analyses, there were no differences between groups with regards to the risk of ER (log rank P = 0.171), discontinuation of AAD before ninety days post-ablation (log rank P = 0.235), or freedom from second ablation (log rank P = 0.147). After multivariable adjustment, patients on amiodarone or dronedarone were more likely to experience LR than those on no AAD [Adjusted Hazard Ratio (AHR) 1.83, 95% CI 1.10-3.04, p=0.02 for amiodarone; AHR 1.79, 95% CI 1.05-3.05, p=0.03 for dronedarone]. Conclusions: Following first-time AF catheter ablation, there were no differences between the presence or absence of AAD and risk of ER, while those prescribed amiodarone or dronedarone in the BP were more likely to experience LR than those on no AAD.

Ventricular premature contractions coupling interval behavior and efficacy of anti-arrhythmic drugs

Abstract Introduction The Idiopathic ventricular arrhythmias are special type of arrhythmia that occurs in the absence of clinically apparent structural heart. They have different pattern of recurrence sporadic, bigeminy, trigeminy, couplets and Ventricular tachycardia runs. They have special behavior of relatively constant coupling interval and recurrence depending on heart rate variability and autonomic nervous system dominance.Objectives: To assess the effect of Coupling interval on the efficacy of different anti-arrhythmic drug. Methods Each subject among 125 consecutive patients with high ventricular premature contractions burden, 24 h ambulatory electrocardiograms were recorded in the absence of anti-arrhythmic drug (control), and during treatment with various anti-arrhythmic drugs. The ratio of the coupling interval (CI) to the preceding R-R intervals was calculated.Patients were treated by different anti-arrhythmic therapy. Efficacy of anti-arrhythmic therapy was documented by ambulatory electrocardiogram for 24 hour by estimating the reduction of Ventricular arrhythmia burden. Results The burden of ventricular premature contractions was reduced effectively (&amp;gt;70% reduction of PVCs burden) in patients receiving BB with RR interval &amp;lt;680 ms, CI/RR &amp;lt;0.4, (P=0.002) (relative tachycardia), while in patients receiving CCB it was effective with RR 650- 830 ms, CI/RR 0.4–0.7, (P=0.04) (average heart rate). While in patients receiving Flecanide were found to have effective therapy with RR &amp;gt;900 ms, CI/RR&amp;gt;0.7, (relative bradycardia) (P=0.005). Conclusion The coupling interval of ventricular premature contractions can predict the efficacy of anti-arrhythmic drugs. The efficacy of anti-arrhythmic therapy may be dependent on the ventricular arrhythmia behavior of the coupling interval and RR interval of the preceding sinus rhythm. Efficacy of different anti-arrhythmic Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Egyptian Ministry of Higher Education

Predictors of freedom from atrial arrhythmia recurrence after cryoballoon ablation for persistent atrial fibrillation: A multicenter study.

We sought to assess (1) clinical outcomes of second-generation cryoballoon (CB) ablation for persistent atrial fibrillation (AF), and (2) the association of baseline and procedural covariates with atrial arrhythmia recurrence (AAR) after ablation. A total of 135 patients (63 ± 11 years, 96 men [71%]) with persistent AF underwent CB ablation at three experienced electrophysiology centers. Freedom from AAR was estimated with the Kaplan-Meier method. A Cox proportional-hazards model was used to estimate the effects of baseline and procedural covariates on the likelihood of AAR. Freedom from AAR at 6, 12, and 18 months was estimated at 91% (95% confidence interval [CI] 86%-96%), 75% (95% CI, 67%-83%), and 53% (95% CI, 43%-65%), respectively. The presence of an implantable cardiac device (Hazard ratio [HR] 3.09; 95% CI, 1.37-7.00; P = .007), a left atrial (LA) diameter > 50 mm (HR 1.69; 95% CI, 1.02-2.79; P = .043), and absence of antiarrhythmic drug (AAD) therapy before the ablation procedure (HR 3.12; 95% CI, 1.72-5.64; P < .001) were associated with AAR. A trend toward an increased risk of AAR was revealed for women (HR 1.73; 95% CI, 0.96-3.11; P = .069). CB ablation for persistent AF resulted in freedom from AAR about that reported for RF ablation. The presence of an implantable cardiac device, LA size, and absence of AAD therapy at baseline were associated with the risk of AAR.

Ablation of atrial fibrillation in patients with Brugada syndrome: A systematic review of the literature.

Supraventricular arrhythmias are common in Brugada syndrome (BS), and notoriously difficult to manage with medical therapy secondary to associated risks. Pulmonary vein isolation (PVI) is often utilized instead, but its outcomes in this population are not well‐known. We aim to provide a holistic evaluation of interventional treatment for Atrial fibrillation (AF) in the BS population. Electronic databases Medline, Embase, Cinahl, Cochrane, and Scopus were systematically searched for publications between 01/01/1995 and 12/31/2017. Studies were screened based on predefined inclusion and exclusion criteria. A total of 49 patients with BS and AF were included. Age range from 28.8 to 64 years, and 77.5% were male. 38 patients were implanted with implantable cardioverter‐defibrillators (ICD) at baseline, and of them, 39% suffered inappropriate shocks for rapid AF. 34/49 (69%) of patients achieved remission following a single PVI procedure. Of the remaining, 13 patients underwent one or more repeat ablation procedures. Overall, 45/49 (91.8%) of patients remained in remission during long‐term follow‐up after one or more PVI procedures in the absence of antiarrhythmic drug (AAD) therapy. Postablation, no patients suffered inappropriate ICD shock. Furthermore, no major complications secondary to PVI occurred in any patient. AF ablation achieves acute and long‐term success in the vast majority of patients. It is effective in preventing inappropriate ICD therapy secondary to rapid AF. Complication rates of PVI in BS are low. Thus, in light of the risks of AADs and risk of inappropriate ICD shocks in the BS population, catheter ablation could represent an appropriate first‐line therapy for paroxysmal atrial fibrillation in BS patients.

Which patients recur as atrial tachycardia rather than atrial fibrillation after catheter ablation of atrial fibrillation?

IntroductionThe ablation gaps have been known as the main mechanism of recurrence as atrial tachycardia (AT) rather than atrial fibrillation (AF) after AF catheter ablation. However, AF organization due to reduction of critical mass or focal trigger may also be the mechanism of AT recurrence. We sought to find out the main clinical factors of recurrence as AT rather than AF after AF ablation in the absence of antiarrhythmic drug effect.MethodsWe analyzed 521 patients (70.8% men, 64.1% paroxysmal AF) who experienced AT or AF recurrence without antiarrhythmic drug effect during 44.7 ± 25.4 months follow-up.ResultsAmong 521 patients with recurrence, 42.0% (219 of 521) recurred with AT. The proportion of AT recurrence was not different between the pulmonary vein isolation only group and additional linear ablation group (45.1% vs. 38.1%, p = 0.128). The absence of hypertension (odds ratio [OR] 0.49, 95% confidence interval [CI] 0.29–0.83, p = 0.007), small left atrial (LA) volume index (OR 0.89 per 10 mL/m2, 95% CI 0.79–1.00, p = 0.049), and high mean LA bipolar voltage (OR 2.03 per 1 mV, 95% CI 1.30–3.16, p = 0.002) were independently associated with AT recurrence, whereas additional linear ablation was not. Among 90 patients who underwent repeat ablation procedure, rates of PV reconnection (p = 0.358) and gap in prior linear ablations (p = 0.269) were not significantly different between AT recurrence group and AF recurrence group.ConclusionThe degree of LA remodeling is significantly associated with recurrence as AT after AF ablation, irrespective of potential ablation gap in linear lesion.

Good responders to catheter ablation for long-standing persistent atrial fibrillation: Clinical and genetic characteristics

BackgroundRadiofrequency catheter ablation (RFCA) for long-standing persistent atrial fibrillation (L-PeAF) is challenging and has a relatively high recurrence rate. We explored clinical and genetic characteristics associated with being good responders (no early or clinical recurrence within 12 months in the absence of anti-arrhythmic drugs) to RFCA among patients with L-PeAF. MethodsOf 1319 patients in the Yonsei AF Ablation Cohort, this study included 141 consecutive patients with L-PeAF (80.9% male, age 57.8±9.7 years) who were followed >12 months after RFCA. ResultsDuring 25 (19–35) months follow-up, the recurrence rate was 39%, and 38 patients (27%) were categorized as good responders, those had a shorter AF duration (p=0.010), and smaller left atrial (LA) size (p=0.033) than others. The rs2106216 (16q22/ZFHX3) genetic polymorphism was independently associated with being a good responder in multivariate analysis (adjusted OR=2.70, 95% CI 1.41–5.14, p=0.003), after adjusting for LA size and AF duration. The rs2106261 had predictive value for clinical recurrence of AF after RFCA among patients with an AF duration 12–65 months (log rank, p=0.025). ConclusionsDespite a relatively high recurrence rate after RFCA for L-PeAF, patients with a shorter AF duration and smaller LA size showed a more favorable outcome. The rs2106216 polymorphism (ZFHX3) was independently associated with being good responders to RFCA for L-PeAF, especially with AF duration 12–65 months.

Surgical Minimally Invasive Pulmonary Vein Isolation for Lone Atrial Fibrillation

Minimally invasive surgical pulmonary vein isolation (SMI-PVI) is an emerging therapy for the treatment of symptomatic drug-refractory atrial fibrillation (AF). Nevertheless, the midterm and long-term results of SMI-PVI remain unknown. The aim of this retrospective multicenter study was to report on midterm efficacy and safety of SMI-PVI. The study design was retrospective, multicentric, and observational. From July 2005 to November 2011, a total of 86 patients with drug-refractory paroxysmal or persistent AF underwent SMI-PVI in three centers. Patients were eligible for SMI-PVI if they had symptomatic, drug-refractory AF or after failed transcatheter pulmonary vein isolation. Success was defined as absence of AF on 24- or 96-hour Holter monitoring during follow-up, in the absence of antiarrhythmic drugs (AADs). The mean ± SD age was 54 ± 11 years, and 78% were men. The median AF duration was 30 months (range, 2-203); paroxysmal AF was present in 86% of the patients, persistent in 14%. Fifteen patients (17%) underwent previous transcatheter ablations. After a median follow-up of 24 months (range, 6-78), 72% of all patients were free from atrial arrhythmias without the use of AADs. With AADs, this was 83%. Major perioperative adverse events occurred in 7 patients (8%). This retrospective multicenter study shows that SMI-PVI is effective at a median follow-up of 24 months for the treatment of mostly paroxysmal drug-refractory AF. Perioperative adverse events do remain a point of caution.

Preprocedural Ventricular Rate Predicts Subsequent Sick Sinus Syndrome after Ablation for Long‐Standing Persistent Atrial Fibrillation

Concealed sick sinus syndrome may become manifest after restoration of sinus rhythm by ablation in patients with long-standing persistent atrial fibrillation (AF). The purpose of this study was to investigate the association between the preprocedural ventricular rate during AF and sinus node function in patients with long-standing persistent AF. Consecutive patients (n = 102) who underwent ablation for long-standing persistent AF were enrolled. We measured the ventricular rate during AF before ablation in the absence of antiarrhythmic drugs. Sinus node function was assessed by electrophysiological study and serial Holter recordings after ablation. Patients in the lowest quartile of ventricular rate during AF had longer corrected sinus node recovery time (1.06 ± 1.39 seconds) than those in the other quartiles (0.54 ± 0.31 seconds; P = 0.006) and lower mean heart rate on 24-hour Holter recording 3 months after ablation (68 ± 9 beats/min vs 75 ± 10 beats/min, P = 0.01). During a mean follow-up of 23 ± 10 months, sick sinus syndrome necessitating permanent pacemaker implantation developed in five (5%) patients, and multivariate analysis revealed that a low ventricular rate during AF rate was an independent risk factor for sick sinus syndrome (odds ratio = 0.90 for a 1 beat/min increase in AF rate, P = 0.04). A low preprocedural ventricular rate during AF indicates the existence of sinus node dysfunction after restoration of sinus rhythm by ablation in patients with long-standing persistent AF.

Flúter auricular común con conducción auriculoventricular 1:1 y QRS estrecho sin fármacos antiarrítmicos concomitantes

Atrial flutter with 1:1 ventricular response is usually a condition associated with the use of antiarrhythmic drugs that achieve slow the flutter cycle length, allowing conduction to the ventricle. We present a short series of cases in which the 1:1 flutter occurred in the absence of antiarrhythmic drugs.

Long-Term Clinical Results of 2 Different Ablation Strategies in Patients With Paroxysmal and Persistent Atrial Fibrillation

Data regarding the long-term efficacy of atrial fibrillation (AF) ablation are still lacking. Two hundred four consecutive patients symptomatic for paroxysmal or persistent/permanent AF were randomly assigned to 2 different ablation schemes: pulmonary vein isolation (PVI) and PVI plus left linear lesions (LL). Primary end point was to assess the maintenance of sinus rhythm (SR) after procedures 1 and 2 in the absence of antiarrhythmic drugs in a long-term follow-up of at least 3 years. Paroxysmal AF- With a single procedure at 12-month follow-up, 46% of patients treated with PVI maintained SR, whereas at 3-year follow-up, 29% were in SR; using the "PVI plus LL" at the 12-month follow-up, 57% of patients were in SR, whereas at the 3-year follow-up, 53% remained in SR. After a second procedure, the long-term overall success rate without antiarrhythmic drugs was 62% with PVI and 85% with PVI plus LL. Persistent/Permanent AF- With a single procedure at the 12-month follow-up, 27% of patients treated with PVI were in SR, whereas at the 3-year follow-up, 19% maintained SR; using the PVI plus LL with a single procedure at the 12-month follow-up 45% of patients were in SR, whereas at the 3-year follow-up, 41% remained in SR. After a second procedure, the long-term overall success rate without antiarrhythmic drugs was 39% with PVI and 75% with PVI plus LL. A long-term follow-up of AF ablation shows that short-term results cannot be considered permanent because AF recurrences are still present after the first year especially in patients who have had "PVI" strategy. PVI isolation plus LL is superior to the PVI strategy in maintaining SR without antiarrhythmic drugs after procedures 1 and 2 both in paroxysmal and persistent AF.

Atrial fibrillation in recipients of cardiac resynchronization therapy device: 1-year results of the randomized MASCOT trial

Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP). The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year. Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF. In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.

Atrial flutter with 1/1 nodal conduction in the absence of antiarrhythmic drugs

International Journal of Clinical PracticeVolume 61, Issue 7 p. 1230-1232 Atrial flutter with 1/1 nodal conduction in the absence of antiarrhythmic drugs A. Arujuna, A. Arujuna Cardiac Department, Royal Devon & Exeter Hospital, Exeter, Devon, UKSearch for more papers by this authorP. Spurrell, P. Spurrell Cardiac Department, Royal Devon & Exeter Hospital, Exeter, Devon, UKSearch for more papers by this authorC. A. Rinaldi, C. A. Rinaldi Cardiac Department, Royal Devon & Exeter Hospital, Exeter, Devon, UKSearch for more papers by this author A. Arujuna, A. Arujuna Cardiac Department, Royal Devon & Exeter Hospital, Exeter, Devon, UKSearch for more papers by this authorP. Spurrell, P. Spurrell Cardiac Department, Royal Devon & Exeter Hospital, Exeter, Devon, UKSearch for more papers by this authorC. A. Rinaldi, C. A. Rinaldi Cardiac Department, Royal Devon & Exeter Hospital, Exeter, Devon, UKSearch for more papers by this author First published: 15 June 2007 https://doi.org/10.1111/j.1742-1241.2005.00718.xCitations: 1 Dr Philip Spurrell, Cardiac Department, Royal Devon & Exeter Hospital, Barrack Road, Exeter EX2 5DW, UKFax: + 44 1626 821 081Email: spurrellp@aol.com Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume61, Issue7July 2007Pages 1230-1232 RelatedInformation

Effects of cardioactive medications on retrograde conduction: Continuing relevance for current devices

Retroconduction (ventriculo-atrial conduction) remains a problem for patients with implanted cardiac rhythm devices. Pacemaker algorithms can detect and terminate endless loop tachycardia (ELT), but actual prevention of ELT may require anti-arrhythmic drugs (AADs). Similarly, AADs can affect ICD rhythm discrimination algorithms that depend on atrio-ventricular ratios. There is concern whether these drugs remain effective during stress situations. Electrophysiologic studies that included retroconduction testing using slow ramp pacing were done in 1332 patients. The presence or absence of retroconduction at baseline and with drug was recorded, as was the rate at block. As a stress surrogate, isoproterenol was used to test retroconduction and reversal of drug-induced block. Procainamide, mexiletine, phenytoin, disopyramide, quinidine, beta-blockers, encainide, and amiodarone caused complete retrograde block or decreased the rate at which block occurred (mean 76% of patients, p < 0.008), whereas digoxin, lidocaine, diltiazem, and verapamil did not. Isoproterenol (in the absence of AADs) increased the rate at block in 82% of 404 patients with retroconduction at baseline (p < 0.005). Of 319 patients without retroconduction at baseline, 134 (42%) developed retroconduction after isoproterenol. Isoproterenol reversed retrograde block in 39% of patients with block on an AAD. Amiodarone, digoxin, and the combination of digoxin plus a beta-blocker were most effective at resisting this reversal of ventriculo-atrial block (80%, 68%, and 75% respectively). Most of the AADs reviewed increase the cycle length at block or abolish retroconduction, while isoproterenol has the opposite effect. Anti-arrhythmic medications, particularly amiodarone, digoxin, and the combination of digoxin plus a beta-blocker may be considered for a patient with multiple ELT episodes or certain ICD detection problems.

Cost analysis of catheter ablation for paroxysmal atrial fibrillation.

RF ablation for paroxysmal atrial fibrillation (PAF) is a curative treatment, which when successful, eliminates the need to take antiarrhythmic drugs, be anticoagulated, and have recurrent physician visits or hospital admissions. The authors performed a retrospective cost comparison of RF ablation versus drug therapy for PAF. The study population consisted of 118 consecutive patients with symptomatic, drug refractory PAF who underwent 1.52 +/- 0.71 RF ablation procedures (range 1-4) for PAF. During a follow-up of 32 +/- 15 weeks, 85 (72%) patients remained free of clinical recurrence in absence of antiarrhythmic drugs. The cost of RF ablation was calculated in the year 2001 euros on the basis of resource use. The mean cost of pharmacologic treatment prior to ablation was 1,590 euros/patient per year. The initial cost of RF ablation for PAF was 4,715 euros, then 445 euros/year. After 5 years, the cost of RF ablation was below that of ongoing medical management, and continued to diverge thereafter. RF catheter ablation may be a cost-effective alternative to long-term drug therapy in patients with symptomatic, drug refractory PAF.

Arrhythmia risk stratification in idiopathic dilated cardiomyopathy based on echocardiography and 12-lead, signal-averaged, and 24-hour Holter electrocardiography

Background To date, considerable controversy exists regarding noninvasive arrhythmia risk stratification in idiopathic dilated cardiomyopathy (IDC). Methods and Results Between 1992 and 1997, 202 patients with IDC without a history of sustained ventricular tachycardia (VT) underwent echocardiography, signal-averaged electrocardiogram (ECG), and 24-hour Holter ECG in the absence of antiarrhythmic drugs. During 32 ± 15 months of prospective follow-up, major arrhythmic events, including sustained VT, ventricular fibrillation, or sudden death, occurred in 32 (16%) of 202 patients. After adjusting for baseline medical therapy and antiarrhythmic therapy during follow-up, multivariate Cox regression analysis identified a left ventricular (LV) end-diastolic diameter ≥70 mm and nonsustained VT on Holter as the only independent arrhythmia risk predictors. The combination of an LV end-diastolic diameter ≥70 mm and nonsustained VT was associated with a 14.3-fold risk for future arrhythmic events (95% confidence interval 2.3-90). To further elucidate the prognostic value of LV ejection fraction, multivariate Cox analysis was repeated with ejection fraction forced to remain in the model. In the latter model, an ejection fraction ≤30% combined with nonsustained VT on Holter was found to be a significant arrhythmia risk predictor with a relative risk of 14.6 (95% confidence interval 2.2-97). Conclusions The combination of an LV end-diastolic diameter ≥70 mm and nonsustained VT on Holter, and the combination of LV ejection fraction ≤30% and nonsustained VT on Holter, identify a subgroup of patients with IDC with a 14-fold risk for subsequent arrhythmic events. These findings have important implications for the design of future studies evaluating the role of prophylactic defibrillator therapy in patients with IDC. (Am Heart J 2000;140:43-51.)

Effect of Heart Rate on T Wave Alternans

T wave alternans (TWA) is a promising technique for detecting arrhythmia vulnerability. Previous studies in animals demonstrated that the magnitude of TWA is dependent on heart rate. However, the effects of heart rate on TWA in humans and the clinical relevance of this effect remain controversial. This was a prospective evaluation of pacing rate and monitoring lead configuration on TWA in subjects undergoing electrophysiologic study. Measurements of TWA were performed on 45 patients in the absence of antiarrhythmic drugs. Recordings were made in normal sinus rhythm and during atrial pacing at 100 and 120 beats/min. Sustained monomorphic ventricular tachycardia (VT) was induced in 29 patients with programmed stimulation. TWA in the vector magnitude lead increased with heart rate, independent of VT inducibility (0.4 +/- 0.7 microV, 1.6 +/- 1.9 microV, and 2.4 +/- 2.1 microV in sinus rhythm and at 100 and at 120 beats/min, respectively; P < 0.001). In addition, the diagnostic performance of TWA for inducible VT was dependent on heart rate (sensitivity 4%, 42%, and 65%, and specificity 100%, 93%, and 63% at 77, 100, and 120 beats/min, respectively). By analyzing orthogonal leads rather than the vector magnitude lead, the sensitivity is increased from 42% to 59% at 100 beats/min, but the specificity is reduced from 93% to 72%. These results indicate that TWA in humans is strongly dependent on heart rate with regard to both magnitude and diagnostic performance. The optimal heart rate for the measurement of TWA is between 100 and 120 beats/min and multiple leads should be monitored.

Heart rate during spontaneous and induced paroxysmal supraventricular tachycardia.

It is generally assumed that paroxysmal supraventricular tachycardia (PSVT) induced during invasive electrophysiological study reproduces the patient's spontaneous, clinical arrhythmia. Even in the absence of antiarrhythmic drugs, however, there may be significant differences in characteristics of the induced and spontaneous arrhythmias. We compared the heart rate of PSVT in 38 patients who had undergone electrophysiological study with induction of PSVT who also had a spontaneous episode of PSVT documented by transtelephonic ECG monitoring during a period when all antiarrhythmic drugs were withheld. The heart rate during spontaneous PSVT was faster than the heart rate of PSVT induced during electrophysiological study; the mean difference was 16 beats/min (P < 0.001). We conclude that heart rate of PSVT induced during electrophysiological study generally underestimates the heart rate of spontaneous PSVT in the antiarrhythmic drug-free state. This may be due to differences in the autonomic and hemodynamic states during spontaneous and induced arrhythmias.

Comparison of number of extrastimuli versus change in basic cycle length for induction of ventricular tachycardia by programmed ventricular stimulation

Objectives. The purpose of this study was to examine the effects of varying basic cycle lengths in a programmed stimulation protocol if up to seven extrastimuli were available at each basic cycle length.Background. There is no uniformly accepted protocol for induction of ventricular tachycardia. Most protocols limit the number of extrastimuli to two or three but use several basic cycle lengths.Methods. Twenty-eight patients with coronary artery disease and documented spontaneous sustained ventricular tachycardia or ventricular fibrillation were studied. In the absence of antiarrhythmic drugs, each patient underwent three inductions of ventricular tachycardia/ventricular fibrillation using sinus rhythm or right ventricular pacing at 600 or 400 ms as the basic cycle length. Up to seven extrastimuli were allowed at each basic cycle length.Results. The maximal yield of clinical tachycardia (96%) was identical for each basic cycle length and was achieved using a maximum of seven, five and four extrastimuli for sinus rhythm and 600 and 400 ms, respectively. A basic cycle length of 400 ms required fewer extrastimuli (2.4 ± 0.7) to induce ventricular tachycardia/ventricular fibrillation than did 600 ms (2.7 ± 1.1, p = 0.014) or sinus rhythm (3.4 ± 1.2, p < 0.001). There was no significant difference in the cycle lengths of the induced ventricular tachycardia, incidence of induced ventricular fibrillation or requirement for direct current countershock.Conclusions. The use of an adequate number of extrastimuli obviates the need for multiple basic cycle lengths for induction of ventricular tachycardia and does not increase induction of unwanted ventricular fibrillation. If only one basic cycle length is used, the ease of inducibility can be quantified in terms of the number of extrastimuli required. Fewer extrastimuli were required for induction of ventricular tachycardia if a basic cycle length of 400 ms was used. These data favor the use of ventricular pacing at a basic cycle length of 400 ms with up to at least four extrastimuli as the standard stimulation protocol for induction of ventricular tachycardia.