Loss of Pace Capture on the Ablation Line During Pulmonary Vein Isolation versus "Dormant Conduction": Is Adenosine Expendable?

INTRODUCTION: Permanent pulmonary vein isolation (PVI) remains an essential goal of ablation therapy in patients with atrial fibrillation. Aim of this study was the intraindividual comparison of unexcitability to pacing along the ablation line versus dormant conduction (DC) as additional procedural endpoints. METHODS: A total of 58 patients with paroxysmal atrial fibrillation (PAF) underwent PVI by circumferential ablation of ipsilateral pulmonary veins (PVs), followed by testing for DC by adenosine administration. Irrespective of the presence of DC, pacing along the ablation line for left atrium capture was performed and additional radio frequency energy applied if necessary. PVs with initial DC were retested after achieving unexcitability. RESULTS: PVI was achieved in 224 of 224 PVs. In 33 of 224 PVs (15%) DC was revealed. At 92 of 112 ablation lines (82%) sites of excitability were found. Three (9%) of the initial 33 PVs with DC showed further DC after achieving unexcitability at repeated testing. Thirty-two of 33 assumed areas of unmasked PV-LA reconduction as revealed by DC-testing showed a corresponding site of excitability on the ablation line. After a follow-up of 11.6 ± 3.4 months 79% of patients were free of arrhythmia. CONCLUSIONS: Pacing for unexcitability can safely identify potential sites of DC and even sites that would have not been detected by testing for DC. Unexcitability, therefore, serves as a suitable and safe procedural endpoint not only for patients with contraindications to adenosine administration. Our data suggest that adenosine may be expendable when achieving unexcitability along the ablation line.

Predictors of successful cardioversion with vernakalant in patients with recent-onset atrial fibrillation.

BACKGROUND: Vernakalant is a novel atrial-selective antiarrhythmic drug able to convert recent-onset atrial fibrillation (AF) with reportedly low proarrhythmic risk. Successful cardioversion predictors are largely unknown. We sought to evaluate clinical and electrocardiographic predictors of cardioversion of recent-onset AF with vernakalant. METHODS: Consecutive patients with AF ≤48 hours admitted for cardioversion with vernakalant (n = 113, median age 62 years, 69 male) were included. Sinus rhythm (SR) within 90 minutes after infusion start was considered to be successful cardioversion. Predictive values of demographics, concomitant therapy, comorbidities, and electrocardiographic parameters were assessed. Atrial fibrillatory rate (AFR), exponential decay, and mean fibrillatory wave amplitude were measured from surface ECG using QRST cancellation and time-frequency analysis. RESULTS: Cardioversion was achieved in 66% of patients. Conversion rate was higher in women than in men (80% vs 58%, P = 0.02) while none of other clinical characteristics, including index AF episode duration, could predict SR restoration. Female gender was predictive of vernakalant's effect in logistic regression analysis (OR = 2.82 95%CI 1.18-6.76, P = 0.020). There was no difference in AFR (350 ± 60 vs 348 ± 62 fibrillations per minute [fpm], P = 0.893), mean fibrillatory wave amplitude (86 ± 33 vs 88 ± 67 µV, P = 0.852), or exponential decay (1.30 ± 0.42 vs 1.35 ± 0.42, P = 0.376) between responders and nonresponders. CONCLUSIONS: Female gender is associated with a higher rate of SR restoration using intravenous (i.v.) vernakalant for recent-onset AF. ECG-derived indices of AF organization, which previous studies associated with effect of rhythm control interventions, did not predict vernakalant's effect.

Pulmonary vein isolation alone in patients with persistent atrial fibrillation: an ablation strategy facilitated by antiarrhythmic drug induced reverse remodeling.

INTRODUCTION: Pulmonary vein isolation (PVI) alone has been thought to be insufficient in patients with persistent atrial fibrillation (PersAF). We hypothesized that preablation treatment of PersAF with a potent antiarrhythmic drug (AAD) would facilitate reverse atrial remodeling and result in high procedural efficacy after PVI alone. METHODS AND RESULTS: Seventy-one consecutive patients (59.4 ± 9.8 years) with PersAF and prior AAD failure were treated with oral dofetilide (768 ± 291 mcg/day) for a median of 85 days pre-PVI. P-wave duration (Pdur) on ECG was used to assess reverse atrial remodeling. Thirty-five patients with paroxysmal (P) AF not treated with an AAD served as controls. All patients underwent PVI alone; dofetilide was discontinued 1-3 mos postablation. In the PersAF patients, the Pdur decreased from 136.3 ± 21.7 ms (assessed postcardioversion on dofetilide) to 118.6 ± 20.4 ms (assessed immediately prior to PVI) (P < 0.001). In contrast, no change in Pdur (122.6 ± 11.5 ms vs. 121.3 ± 13.7 ms, P = NS) was observed in PAF patients. The 6 and 12 mos AAD-free response to ablation was 76% and 70%, respectively, in PersAF patients, similar to the 80% and 75%, response in PAF patients (P = NS). A decline in Pdur in response to dofetilide was the only predictor of long-term clinical response to PVI in patients with PersAF. CONCLUSIONS: Pre-treatment with AAD resulted in a decrease in Pdur suggesting reverse atrial electrical remodeling in PersAF patients. This may explain the excellent clinical outcomes using PVI alone, and may suggest an alternative ablation strategy for PersAF.

Comparison of the clinical outcome after pulmonary vein isolation based on the appearance of adenosine-induced dormant pulmonary vein conduction.

BACKGROUND: The elimination of transient pulmonary vein (PV) reconduction (dormant PV conduction) revealed by adenosine in addition to PV isolation reduced the atrial fibrillation (AF) recurrence after catheter ablation. The dormant PV conduction is induced in approximately half of the AF patients that undergo PV isolation. The present study compared the clinical outcome of AF ablation in patients whose dormant PV conduction was eliminated by additional radiofrequency applications with the outcome in patients without dormant conduction. METHODS: A total of 233 consecutive patients (206 male, 54.2 +/- 10.1 years) that underwent AF ablation were included in the present study. Dormant PV conduction was induced by the administration of adenosine triphosphate after PV isolation and was eliminated by supplemental radiofrequency application. All patients were followed up for >12 months (mean 903 days) after the first ablation. RESULTS: Following PV isolation, dormant PV conduction was induced in 139 (59.7%) of 233 patients and was successfully eliminated in 98% (223/228) of those in the first ablation procedure. After the first procedure, 63.9% (149/233) of patients were free from AF recurrence events. The success rates of a single or final AF ablation in patients with the appearance of the dormant PV conduction were similar to those of patients without dormant conduction (P = .69 and P = .69, respectively). CONCLUSIONS: Dormant PV conduction was induced in over half of the patients with AF. After the elimination of adenosine triphosphate-induced reconnection, the clinical outcome of patients with the dormant PV conduction was equivalent to that of patients without conduction.

Coronary morphology and conduction system disturbance induced by therapeutic embolization of the coronary septal artery.

BACKGROUND: Percutaneous transluminal septal myocardial alcohol ablation (PTSMAA) is not a procedure without complications. It may produce heart arrhythmias, especially those due to disturbances of atrioventricular (AV) and interventricular (IV) electrical conduction. OBJECTIVE: The goal of this study was to evaluate the relationship between the anatomical patterns of the right coronary artery and the left anterior descending artery (LAD) and to relate them to the AV and IV bundle branch blocks provoked by PTSMAA. METHOD: Twenty patients with obstructive hypertrophic cardiomyopathy resistant to treatment with drugs successfully underwent PTSMAA. Electrocardiographic analyses were done before and after PTSMAA, and the results were compared with the abnormal septal anatomy. RESULTS: The effectiveness of PTSMAA was obtained in 18 (90%) of the 20 patients by ethanolization of the first great septal branch. In the other 2 patients (10%), 2 septal branches underwent alcoholization. First-grade temporary AV block (AVB) was observed in 6 patients (30%). Ten patients experienced severe bradycardia due to total AVB that required a temporary pacemaker, but 3 of the patients (15%) required a permanent pacemaker. Fourteen patients (70%) experienced permanent complete right branch block, and 2 developed incomplete left anterior block and incomplete left posterior block. Six patients presented with no electrical conduction disturbance at all. CONCLUSION: According to the results of the present investigation with the AV node artery derived from the right coronary artery in all cases, complete and permanent AV conduction system blockade occurred after PTSMAA in all types of anatomy regarding the observed LAD.

A new approach for contrast-enhanced X-ray imaging of the left atrium and pulmonary veins for atrial fibrillation ablation: rotational angiography during adenosine-induced asystole.

AIMS: Atrial fibrillation ablation is a complex procedure that requires detailed anatomic information about left atrium (LA) and pulmonary veins (PVs). The goal of this study was to test rotational angiography of the LA during adenosine-induced asystole as an imaging tool in patients undergoing atrial fibrillation ablation. METHODS AND RESULTS: Seventy patients with paroxysmal or persistent atrial fibrillation undergoing PV isolation were included. After transseptal puncture, adenosine (30 mg) was given intravenously, and during atrioventricular block, contrast medium was directly injected in the LA; a rotational angiography was performed (right anterior oblique 55 degrees to left anterior oblique 55 degrees). Rotational angiography images were assessed qualitatively in all patients and quantitatively in 45 patients in comparison with computed tomography (CT) images. The majority of rotational angiography imaging data (94%) were deemed at least 'useful' in delineating the LA-PV anatomy. The so-called 'ridge' between left superior PV and left atrial appendage was delineated in 90% of the patients. All accessory PVs were independently identified by rotational angiography and CT. A blinded quantitative comparison of PV ostial diameters showed an excellent correlation between rotational angiography and CT measurements (r > 0.90 for all PVs). No serious adverse effects occurred in association with adenosine. CONCLUSION: Intra-procedural contrast-enhanced rotational angiography of the LA-PV during adenosine-induced asystole is feasible and provides anatomical information of high diagnostic value for atrial fibrillation ablation.

Haloperidol versus ondansetron for prophylaxis of postoperative nausea and vomiting.

BACKGROUND: Haloperidol is effective for postoperative nausea and vomiting prophylaxis, but there are almost no data comparing it to 5-HT(3) antagonists. METHODS: Two hundred forty-four adults were randomized to receive i.v. haloperidol 1 mg or ondansetron 4 mg, during general anesthesia. Nausea, vomiting, need for rescue, sedation, extrapyramidal effects, QTc intervals, and time to postanesthesia care unit discharge were evaluated with a third-party blind design. RESULTS: There was no intergroup difference in any measure of efficacy or toxicity. Haloperidol and ondansetron subjects (78.2% and 76.8%) had complete response. Postoperatively, prolonged QTc occurred in 28.9% and 22.1% (N.S.). CONCLUSIONS: In a mixed surgical population, the efficacy and toxicity of postoperative nausea and vomiting prophylaxis with haloperidol 1 mg was not significantly different from ondansetron 4 mg.

Pharmacologic control of rhythm: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery.

Of the 128 articles evaluated on the overall topic of atrial fibrillation (AF) after cardiac surgery, only 19 studies dealing with pharmacologic heart rhythm control were relevant for inclusion in this analysis, indicating the relative paucity of evidence-based studies addressing this topic. We found limited data on guiding treatment for the rhythm control of AF following cardiac surgery in patients who do not require urgent cardioversion; therefore, the choice of an antiarrhythmic drug needs to be guided by patient characteristics. Based on limited available evidence, amiodarone is recommended for pharmacologic conversion of postoperative AF and AFL in patients with depressed left ventricular function who do not need urgent electrical cardioversion. This recommendation is made largely because of the effectiveness of amiodarone and also because of its relatively favorable side-effects profile. Sotalol and class 1A antiarrhythmic drugs are reasonable choices for patients with coronary artery disease who do not have congestive heart failure. There are currently no definitive data to guide the decision about the duration of antiarrhythmic drug therapy for patients with AF following cardiac surgery. Most protocols continue therapy with the antiarrhythmic drug for 4 to 6 weeks following surgery, but evidence from randomized studies is lacking.

[Ineffective atrial pacing and cardiac arrest in a 80-year old woman with hyperkalemia]. / Nieskuteczna stymulacja przedsionkowa i zatrzymanie krazenia u osiemdziesiecioletniej chorej z hiperkaliemia.

A case of 80-year-old woman with marked hyperkalemia in the course of chronic treatment with angiotensin converting enzyme (ACE) inhibitors and spironolactone is presented. AAI pacemaker was implanted three months ago. The ECG revealed a nodal rhythm, ineffective AAI pacing and other typical features of hyperkalemia. After normalisation of potassium level the ECG changes disappeared. Potential mechanism of the nodal rhythm during ineffective atrial pacing is discussed.

Cardiovascular and antidepressant effects of imipramine in the treatment of secondary depression in patients with ischemic heart disease.

The authors report on 12 men with ischemic heart disease who developed secondary depression following myocardial infarction or coronary artery bypass-graft surgery and were treated with imipramine hydrochloride for 4 weeks. Imipramine had an antiarrhythmic effect, manifested by reduction in premature ventricular contractions during treatment. This drug did not produce clinically significant disturbances in cardiac conduction, but orthostatic hypotension led to early termination of the drug treatment in 1 subject. Imipramine treatment was associated with significant improvement in both observer-rated and patient-rated depression scales.

Effects of amiodarone on the P-wave triggered signal-averaged electrocardiogram in patients with paroxysmal atrial fibrillation and coronary artery disease.

The effects of a 6-week treatment with amiodarone on the P-wave triggered signal-averaged electrocardiogram in patients with paroxysmal atrial fibrillation and coronary artery disease have been studied. Amiodarone favorably influences P-wave triggered signal-averaged electrocardiographic parameters, predominantly in patients in whom amiodarone is effective in preventing paroxysmal atrial fibrillation.

Repolarization measures and their relation to sex hormones in postmenopausal women with cardiovascular disease receiving hormone replacement therapy.

Women are more susceptible to the development of Torsades de Pointes ventricular tachycardia and have a longer heart rate-corrected QT interval than men. A causal role for estrogen has been implicated. The purpose of this study was to investigate if hormone replacement therapy (HRT) resulted in any changes in noninvasive depolarization and repolarization measurements, and to study their relation to circulating concentrations of sex hormones. Sixty postmenopausal women with cardiovascular disease (mean age 59 +/- 7 years; range 44 to 75) were randomized to receive oral conjugated estrogens, transdermal estradiol-17-beta (both with addition of progestins), or placebo. QRS, QT, and JT intervals and their dispersion on 12-lead electrocardiograms were analyzed at baseline, and after 6 and 12 treatment cycles of HRT. Blood samples for analyses of serum concentration of estrogens and androgens were obtained on the same occasions. Neither mean RR, QT, QTc, JT, and JTc intervals, nor QT and JT dispersion changed during treatment. There was a significant inverse relation between the mean JTc interval and the serum concentration of estradiol-17-beta, independent of age, testosterone levels, and abdominal obesity. There was also a significant inverse relation between the change in androstenedione levels and the change in QT interval (Spearman -0.35, p = 0.028) or JT interval (Spearman -0.41, p = 0.009) at 6 treatment cycles compared with baseline. In conclusion, treatment with oral conjugated estrogens or transdermal estradiol-17-beta combined with progestins did not alter depolarization or repolarization measurements. However, the inverse relation between repolarization and androgens fits with an effect of androgens on repolarization in postmenopausal women.

Amiodarone in long term prophylaxis.

Amiodarone is predominantly a potassium channel inhibitor which prolongs repolarisation and refractoriness, and thus qualifies as a Group III antiarrhythmic agent. In addition, it possesses a variety of electrophysiological actions such as sodium channel blockade, calcium channel blockade and noncompetitive inhibition of adrenergic receptors. In the studies reported below, the incidence of successful treatment of refractory ventricular arrhythmias with amiodarone appears to range between 50 to 60% in the first year. However, there are very few prospective randomised studies which assess its efficacy in controlling ventricular tachycardia in comparison with placebo or another antiarrhythmic compound. As there have been no controlled studies to examine the impact of amiodarone in preventing ventricular tachycardia in survivors of cardiac arrest compared with either no treatment or with alternative therapies, the actual efficacy of amiodarone in patients who have survived a cardiac arrest is virtually unknown. Although there are indications that amiodarone reduces the incidence of sudden death in patients with malignant arrhythmias, definitive evidence based on controlled trials is not available.

Verapamil potassium cardioplegia and cardiac conduction.

This clinical study analyzes the effect of potassium cardioplegic solution containing verapamil hydrochloride (1 mg/L) on cardiac conduction after release of the aortic cross-clamp and throughout recovery. Fifty consecutive patients undergoing open-heart operation were studied as a unit for postoperative conduction abnormalities. They were also analyzed in groups based on spontaneous ventricular conversion to regular rhythm (54%) and the need for single DC cardioversion (32%), or multiple DC cardioversions (14%). Results showed that spontaneous ventricular conversion had no relationship to aortic cross-clamp time and that DC cardioversion using 10 Ws had no detrimental effects on the myocardium or incidence of conduction abnormalities. The need for transient intraoperative pacing was lowest with spontaneous ventricular conversion, but not statistically different from single or multiple DC cardioversions. Only 3 patients (6%) required pacing in the intensive care unit. The incidence of postoperative atrial and ventricular arrhythmias was similar in all groups, and no deaths or episodes of malignant ventricular arrhythmias occurred. This study concludes that verapamil potassium cardioplegia is associated with excellent myocardial protection and a high incidence of transient intraoperative dysfunction of the atrioventricular node (70%) but a low incidence of postoperative pacing. Benign postoperative arrhythmias occur, but at hospital discharge, few conduction abnormalities (10%) persist.

Atrial flutter with 1:1 conduction after administration of the antimalarial drug mefloquine.

Antimalarial drugs are well known for their cardiovascular toxicity. Quinine, the most famous antimalarial agent, mostly causes bradycardia. Quinidine, its dextrorotatory isomer, may cause 1:1 atrioventricular (AV) conduction during atrial flutter. The newly developed drug mefloquine was reported to have fewer cardiac side effects. We describe a 63-year-old male patient with atrial flutter in whom mefloquine use was associated with 1:1 AV conduction, and who then responded to therapy with digoxin and sotalol. The patient had a history of palpitations. This case report emphasizes that mefloquine should be used with caution in patients with a history of palpitations or underlying heart disease.

[Comparative effects of anti-arrhythmia agents on ventricular refractory period and prevention of ventricular tachycardia induced by stimulation]. / Effets comparés des antiarythmiques sur la période réfractaire ventriculaire et sur la prévention des tachycardies ventriculaires induites par stimulation.

The efficacy of antiarrhythmic drugs is attributed to their actions on the refractory periods or conduction velocity in the reentry circuit. The aim of this study was to determine the relationship between these factors and the prevention of electrically inducible ventricular tachycardia (VT). Twenty-seven patients with sustained monomorphic postinfarction VT underwent programmed stimulation under basal conditions and after administration of oral Class I antiarrhythmic drugs. The protocol of stimulation consisted of delivering one to three extrastimuli to the right ventricular apex on two basic cycle lengths. Sustained VT was induced in all patients. After the same protocol under antiarrhythmic therapy (1 to 5 tests, average 2.9 +/- 1) sustained VT could not be induced in 12 patients (44%). The effective right ventricular refractory period was significantly increased in patients without inducible VT under treatment (247 +/- 18 versus 302 +/- 26 ms). The increase in the right ventricular effective refractory period in patients with persistence of inducible VT was much less (from 270 +/- 28 to 287 +/- 30 ms). In all patients in whom several antiarrhythmic drugs were tested the right ventricular effective refractory period was higher when the treatment was judged to be effective (299 +/- 27 ms) than ineffective (272 +/- 27, p < 0.02). The prevention of inducible VT by class I antiarrhythmic agents seems therefore to be related to their effect on the ventricular refractory period.

Atropine versus glycopyrrolate. A study using repeated doses of suxamethonium in man.

Intermittent doses of suxamethonium have been known to result in bradycardia changes in cardiac rhythm. In order to assess the efficacy of a newer quaternary ammonium antimuscarinic, glycopyrrolate, on the cardia effects of intermittent suxamethonium, 28 patients received this drug intravenously just before induction of anesthesia. For comparison, 28 other patients were given atropine. In the atropine series, three patients developed bradycardia while none of those of the glycopyrrolate series did so. In addition, more patients had cardiac arrhythmias in the atropine group. Although no statistically significant differences were seen, clinically, glycopyrrolate seems to afford better protection against the cardiac changes resulting from intermittently administered suxamethonium.

[An unusual cause of cardiac arrest]. / Arresto cardiaco da causa insolita.

The long QT syndrome is characterized by the observed association of "torsade de pointes" and the prolongation of the QT interval on the electrocardiogram. Acquired long QT syndrome typically affects older individuals, being often associated with the action of some drugs. Hypokalemia is a frequent cause of QT lengthening on the electrocardiogram. Chronic assumption of licorice may be an unusual cause of hypokalemia, due to its mineralocorticoid-like action. In this paper we describe a case of cardiac arrest due to "torsade de pointes" resulting from a marked hypokalemia caused by the patient's habit of eating daily a not negligible quantity of licorice.

Treatment of atrial fibrillation.

Atrial fibrillation is a very common arrhythmia and frequently seen by general practitioners. Its rational management entails careful consideration of the goals of therapy. These differ from patient to patient and may include control of ventricular rate, conversion to and maintenance of sinus rhythm and prophylaxis against thromboembolism. This article will focus on the various therapeutic agents available for achieving these aims and will attempt to provide some guidance through what has become a confusing maze of potential therapeutic strategies.