Direct conversion of atrial flutter to sinus rhythm with low-output, short-duration transesophageal atrial pacing

BACKGROUND AND HYPOTHESIS: Transesophageal atrial pacing (TAP) is useful for terminating paroxysmal non-self terminating atrial flutter (PAF); however, high output pacing of long stimulus duration causes severe symptoms such as chest pain. The objective of this study was to investigate the effect of low-output, short-duration TAP on the conversion of PAF. METHODS: We applied low-output (within 15 mA with a pulse duration of 10 ms), short-duration (within 4 s) TAP in 31 patients (50 +/- 19 years) with PAF. Transesophageal pacing was delivered with 10 pulses of burst pacing at intervals that were 20 ms shorter than those of the flutter wave length. When the conversion was unsuccessful, we delivered 20 pulses of burst pacing. RESULTS: Sixteen patients (52%) were converted directly to sinus rhythm and 12 (38%) to atrial fibrillation. Transesophageal pacing was ineffective in 3 (10%) patients. The duration of atrial flutter, maximum flutter wave amplitude, effective pacing intervals, underlying heart diseases, and cardiac function were not different between patients who had direct conversion to sinus rhythm and those converted to atrial fibrillation. The patients who had direct conversion to sinus rhythm had longer flutter wave cycle lengths than those converted to atrial fibrillation (248 vs. 221 ms, p < 0.005). No patient had complications and complained of any symptoms. CONCLUSION: Low-output, short-duration TAP was useful to convert PAF directly to sinus rhythm without side effects.     

Transesophageal echocardiographic predictors for maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation

The aim of this study was to assess the value of transesophageal echocardiography (TEE) in patients with atrial fibrillation in predicting restoration and maintenance of sinus rhythm after electrical cardioversion. TEE was performed in 62 patients with atrial fibrillation before their first elective cardioversion. Clinical variables evaluated were: age, gender, duration, and etiology of atrial fibrillation. TEE variables included: left atrial (LA) length, width, and size, LA annulus size, as well as presence of LA spontaneous contrast, thrombus and mitral regurgitation, LA appendage size and flow, and left ventricular function. Based on initial outcome of cardioversion, patients were grouped into patients who remained in atrial fibrillation and in whom sinus rhythm was restored. The latter group of patients was followed for 1 year, and grouped into patients who reverted to atrial fibrillation and in whom sinus rhythm was maintained. Successful cardioversion was achieved in 50 of 62 patients (81%). None of the clinical or TEE variables were related to initial outcome. At 1-year follow-up, 29 of 50 patients (58%) who underwent successful cardioversion continued to have sinus rhythm. The following variables were related to maintenance of sinus rhythm: duration of atrial fibrillation (6.7 +/- 7.3 vs 2.0 +/- 2.4 months; p < 0.005); LA length (6.2 +/- 0.7 vs. 5.5 +/- 1.0 cm; p < 0.008); width (5.1 +/- 0.5 vs. 4.5 +/- 0.7 cm; p < 0.002); size (26.4 +/- 5.0 vs 19.8 +/- 6.5 cm2; p < 0.0005); annulus size (4.0 +/- 0.2 vs 3.7 +/- 0.3 cm; p < 0.0005); presence of LA spontaneous contrast (13 [62%] vs 4 [14%]; p < 0.002), and LA appendage flow (19 +/- 8 vs 36 +/- 15 cm/s; p < 0.0005). In multivariate logistic regression analysis, LA annulus size, but especially LA appendage flow, were significantly associated with maintenance of sinus rhythm. Thus, in TEE-guided electrical cardioversion of atrial fibrillation, variables often used to assess thromboembolic risk may also be used to predict 1-year outcome of cardioversion.     

Drugs for conversion of atrial fibrillation

Atrial fibrillation is the most common arrhythmia in patients visiting a primary care practice. Although many patients with atrial fibrillation experience relief of symptoms with control of the heart rate, some patients require restoration of sinus rhythm. External direct current (DC) cardioversion is the most effective means of converting atrial fibrillation to sinus rhythm. Pharmacologic cardioversion, although less effective, offers an alternative to DC cardioversion. Several advances have been made in antiarrhythmic medications, including the development of ibutilide, a class III antiarrhythmic drug indicated for acute cardioversion of atrial fibrillation. Other methods of pharmacologic and nonpharmacologic cardioversion remain under development. Until the results of several large-scale randomized clinical trials are available, the decision to choose cardioversion or maintenance of sinus rhythm must be individualized, based on relief of symptoms and reduction of the morbidity and mortality associated with atrial fibrillation.     

Low-dose amiodarone versus sotalol for suppression of recurrent symptomatic atrial fibrillation

The goal of this work is to study the consequences of the last on variations of the blood pressure (BP) in the course of 24 hours. From 1994 to 1997 we have selected 99 hypertensive patients and studied their BP profile. This study included 72 women and 27 men. Their age varies from 22 to 72 years (average 56.7 +/- 9 years). All these patients has an ambulatory blood pressure measurement (ABPM) before the fast and during Ramadan. Before Ramadan the period of the sleep goes from 10 pm +/- 1 h to 8 am +/- 1 h. During the month of Ramadan, the sleep lasts from 0 h +/- 1 to 9 am +/- 1 h. [table: see text] No statistically significant difference is noted between these 2 periods neither for the systolic BP (SBP) nor for the diastolic BP (DBP), for the BP of 24 hours, and the diurnal and nocturnal periods. We have then the compared the hourly average on 24 hours of the 99 patients. We observed that during the month of Ramadan the peak of the awakening is delayed by 2 hours and the nocturnal through is delayed by 1 hour. After this study, which is the first one to deal with variations of blood pressure during the fast of Ramadan we can confirm that in patients with essential hypertension without complications, the fast is well supported. The variations of BP are minimal and are related to the variations of the sleep, activity and eating pattern.     

Short deceleration time of mitral inflow E velocity: prognostic implication with atrial fibrillation versus sinus rhythm

The present study retrospectively identified 367 patients who had restrictive physiology as defined by deceleration time < or = 130 msec; 293 were in sinus rhythm (SR) (194 men and 99 women; mean age 64 +/- 14 years) and 74 were in atrial fibrillation (AF) (51 men and 23 women; mean age 72 +/- 11 years; p < 0.001). Both groups had similar underlying diagnoses and no significant difference in Doppler indices (E wave, 96 +/- 23 vs 99 +/- 22 cm/sec in SR and AF, respectively; deceleration time, 116 +/- 12 vs 116 +/- 13 msec; and left ventricular outflow tract time velocity integral, 14.8 +/- 4.8 vs 14.5 +/- 4.4 cm). Left ventricular ejection fraction was significantly lower in SR patients (29% +/- 16% vs 39% +/- 20%; p = 0.0003). There were 120 deaths (41%) in the SR group and 35 (47%) in the AF group (median follow-up for both groups, 2.2 years). Restrictive physiology as defined by Doppler echocardiography (deceleration time < or = 130 msec) appears to predict a similar poor prognosis with AF as with SR.     

The effect of sotalol hydrochloride therapy on atrial signal-averaged ECG in patients with paroxysmal atrial fibrillation

BACKGROUND: There has been a continuing public debate about assisted suicide and the proper role, if any, of physicians in this practice. Legislative bans and various forms of legalization have been proposed. METHODS: We mailed questionnaires to three stratified random samples of Michigan physicians in specialties likely to involve the care of terminally ill patients: 500 in the spring of 1994, 500 in the summer of 1994, and 600 in the spring of 1995. Similar questionnaires were mailed to stratified random samples of Michigan adults: 449 in the spring of 1994 and 899 in the summer of 1994. Several different questionnaire forms were used, all of which included questions about whether physician-assisted suicide should be banned in Michigan or legalized under certain conditions. RESULTS: Usable questionnaires were returned by 1119 of 1518 physicians eligible for the study (74 percent), and 998 of 1307 eligible adults in the sample of the general public (76 percent). Asked to choose between legalization of physician-assisted suicide and an explicit ban, 56 percent of physicians and 66 percent of the public support legalization, 37 percent of physicians and 26 percent of the public preferred a ban, and 8 percent of each group were uncertain. When the physicians were given a wider range of choices, 40 percent preferred legalization, 37 percent preferred "no law" (i.e., no government regulation), 17 percent favored prohibition, and 5 percent were uncertain. If physician-assisted suicide were legal, 35 percent of physicians said they might participate if requested--22 percent would participate in either assisted suicide or voluntary euthanasia, and 13 percent would participate only in assisted suicide. Support for physician-assisted suicide was lowest among the strongly religious. CONCLUSIONS: Most Michigan physicians prefer either the legalization of physician-assisted suicide or no law at all; fewer than one fifth prefer a complete ban on the practice. Given a choice between legalization and a ban, two thirds of the Michigan public prefer legalization and one quarter prefer a ban.     

Intravenous propafenone: efficacy and safety in the conversion to sinus rhythm of recent onset atrial fibrillation--a single-blind placebo-controlled study

Normal right-handed subjects were required to make pitch comparisons of complex tones in which the fundamental frequency was either present or absent. In both conditions, tones were presented monaurally. An increase in left-ear superiority was observed in the response time measurements when the fundamental was absent. These findings support the notion that the right hemisphere possesses a special mechanism for pitch computation.     

Power spectral analysis of heart period variability of preceding sinus rhythm before initiation of paroxysmal atrial fibrillation

Time domain analysis of heart period variability in patients without structural heart disease demonstrated increased parasympathetic modulation before paroxysmal atrial fibrillation (AF) occurring predominantly at night. However, diurnal differences in autonomic activity preceding AF episodes in a diverse patient population have not been assessed. Accordingly, we performed spectral analysis of heart period variability on Holter recordings during sinus rhythm preceding AF in 29 patients, 17 with night and 12 with day episodes. Samples taken 5, 10, and 20 minutes before AF onset were compared. Normalized high-frequency (HF) spectral power change was greater when comparing the interval 10 to 5 minutes with 20 to 10 minutes preceding AF in 26 of 29 patients (0.09 +/- 0.07 vs 0.03 +/- 0.02; p < 0.0001). HF spectral power increased before 3 of 12 AF episodes during the day compared with 15 of 17 AF episodes during the night (p = 0.001). Nocturnal AF episodes were preceded by increased HF spectral power in the 5- versus the 20-minute sample expressed as natural logarithm-transformed values (5.6 +/- 4.8 vs 4.2 +/- 4.0; p < 0.005) and normalized values (0.19 +/- 0.09 vs 0.10 +/- 0.07; p < 0.02), a decrease in low-frequency/HF ratio (1.05 +/- 0.61 vs 2.21 +/- 1.75; p < 0.05) and heart rate (60 +/- 13 vs 71 +/- 13 beats/min; p = 0.06). Structural heart disease was more common with daytime than nocturnal AF episodes (58% vs 18%, p < 0.05). In conclusion, HF spectral power change was increased preceding most AF episodes. However, diurnal differences were demonstrated. Contrary to daytime AF, increased parasympathetic activity preceded predominantly nocturnal AF, mostly in younger patients with structurally normal hearts.     

Intravenous calcium chloride in the conversion of paroxysmal supraventricular tachycardia to normal sinus rhythm

OBJECTIVE: To determine whether a specially designed antisuction device can prevent the bacterial contamination of the drive air lines of the dental turbine that is caused by suction when the turbine is stopped. STUDY DESIGN: A dental unit with and without the antisuction device and three different types of sterilized handpieces were used in the tests. Each turbine was operated in air, then submerged into a bacterial suspension of E. coli and enterococci for 3 seconds, removed, and stopped. This procedure was repeated 10 times. Possible bacterial contamination of the drive air lines was examined by submersing the head of a sterilized handpiece with the turbine running into a nutrient broth for 30 seconds. The broth was incubated at 35 degrees C up to 2 days. RESULTS: After use of the conventional dental unit, bacterial growth of drive air lines was found in 10 of 150 broth samples. After the installation of the antisuction device no bacterial growth was found in any of the 138 samples. The difference in the contamination frequencies is statistically significant (p = 0.011, Fisher's two-sided exact test). CONCLUSIONS: The drive air lines of the turbine in the dental unit may become contaminated despite the sterilization of handpieces. The antisuction device installed into the dental unit was found to prevent the contamination. With the exception of possibly immunocompromised patients, the transmission of microbes by exhaust air may be too small to cause infections. However, transmission of oral material between patients should be prevented in dental practice.     

Analysis of vagal effects on ventricular rhythm in patients with atrial fibrillation

1. Animal studies suggest that the heart-rate-lowering effect of vagal stimulation during atrial fibrillation is due to: (1) a direct depressant effect on atrioventricular node conductivity, (2) enhancement of concealed atrioventricular nodal conduction of atrial impulses through augmenting fibrillatory activity, thereby indirectly prolonging atrioventricular nodal refractoriness. The purpose of the present study was to analyse these effects in man. 2. Sixteen patients with chronic atrial fibrillation were studied. After administration of propranolol (0.2 mg/kg intravenously) baseline ventricular rhythm was recorded (500 R-R intervals). Recordings were repeated after methylatropine (0.02 mg/kg intravenously). The shortest R-R interval was taken to represent atrioventricular nodal refractoriness. The ratio of the longest to the shortest R-R interval and the coefficient of variation of R-R intervals were used as parameters of concealed conduction. 3. Methylatropine foremost shortened long R-R intervals: values for the mean, shortest and longest R-R intervals decreased from 834 to 685 ms (-18%) (P < 0.001), 573 to 498 ms (-13%) (P < 0.001) and 1228 to 924 ms (-25%) (P < 0.001), respectively. Accordingly, the ratio of the longest to the shortest R-R interval decreased: 2.12 to 1.89 (-11%) (P < 0.05). Also, the coefficient of variation decreased: 0.24 to 0.20 (-17%) (P < 0.05). 4. This study supports the contention that vagal stimulation lowers ventricular rate during atrial fibrillation both by exerting a direct effect on the atrioventricular node and by augmenting concealed conduction.     

Comparisons of oral propafenone and sotalol as an initial treatment in patients with symptomatic paroxysmal atrial fibrillation

The main goal of this study is to evaluate the safety and efficacy of propafenone versus sotalol as an initial choice of treatment in patients with symptomatic paroxysmal atrial fibrillation (AF), according to a double-blind randomized system. In the oral propafenone group (n = 41), 2 patients (5%) discontinued therapy because of gastrointestinal discomfort in 1 and dizziness in the other. Thirty-one (79%) of the 39 patients who continued the treatment had effective response to oral propafenone (>75% reduction of symptomatic arrhythmic attacks) on a mean dose of 663 +/- 99 mg/day with a decrease in attack frequency from 10 +/- 3 to 2 +/- 1 times per week. In the oral sotalol group (n = 38), 4 patients (11%) discontinued treatment because of dizziness in 2 and symptomatic bradycardia in 2. Twenty-six of the 34 patients (76%) who continued the treatment had effective response to oral sotalol on a mean dose of 200 +/- 57 mg/day with a decrease in attack frequency from 11 +/- 3 to 2 +/- 1 times per week. Comparisons of the results between propafenone and sotalol groups showed a similar incidence of intolerable (2 of 41 vs 4 of 38, p = 0.42) and tolerable side effects (10 of 39 vs 8 of 34, p = 1.0). The attack frequency at baseline (11 +/- 3 vs 10 +/- 4 times per week, p = 0.23) and after treatment (3 +/- 1 vs 3 +/- 2 times per week, p = 0.85) did not differ significantly between the 2 groups. The incidence of effective response to drugs was also similar (31 of 39 vs 26 of 34, p = 0.78). Furthermore, the decrease of symptom scores (-32 +/- 8% vs -29 +/- 7%, p = 0.18) and percentage decrease of ventricular rate (-15 +/- 4% vs -18 +/- 4%, p = 0.10) during AF were also similar between the 2 groups. In conclusion, oral propafenone and sotalol are equally effective and safe in preventing attacks and alleviating symptoms of paroxysmal AF.     

Right atrial isolation for atrial fibrillation associated with atrial septal defect

Two patients with atrial fibrillation associated with an atrial septal defect underwent simultaneous surgical correction of the atrial septal defect and right atrial isolation. The right atrium was surgically isolated while the continuity with the sinoatrial node was preserved in the remainder of the heart. After the operation, the patients maintained normal sinus rhythm for 99 and 65 months. Thus, right atrial isolation offers an alternative to the current surgical treatment for atrial fibrillation associated with an atrial septal defect.     

Echocardiographic factors predicting the maintenance of sinus rhythm one year after cardioversion for non-valvular atrial arrhythmias]

Echocardiographic factors predictive of the maintenance of sinus rhythm after successful cardioversion were investigated in 94 patients with non-valvular atrial arrhythmias of recent onset. Seventy-five patients with atrial fibrillation and 19 with atrial flutter admitted for reduction of their arrhythmias underwent transthoracic and transoesophageal echocardiography. After excluding a thrombus in the left atrial appendage or checking that it had disappeared (5 patients), and electrical (n = 74) or pharmacological (n = 20) cardioversion was successfully performed. The maintenance of sinus rhythm (n = 44) or recurrence of arrhythmia (n = 50) were controlled every 3 months for one year. The mean value of the peak positive blood flow in the left atrial appendage was 38 +/- 20 cm/s for the whole group. It was not possible to identify an echocardiographic parameter predictive of maintenance of sinus rhythm at one year either in the whole group or in the subgroups with atrial flutter or atrial fibrillation. In the group in atrial flutter, the mean value of the peak positive blood flow in the left atrial appendage was significantly greater than in the group with atrial fibrillation: 49 +/- 22 cm/s vs 35 +/- 18 cm/s, respectively; p < 0.05. The peak of positive flow in the left atrial appendage was statistically related to indirect parameters of left atrial function and of left ventricular function in the group with atrial fibrillation but only with parameters of left ventricular function in the smaller group with atrial flutter.     

Five-year experience with the maze procedure for atrial fibrillation

Between September 25, 1987, and December 31, 1992, 75 patients (53 men, 22 women; average age, 52 years) underwent the maze procedure for the treatment of atrial fibrillation. Six patients had undergone a previous cardiac operation and 28% underwent concomitant cardiac procedures in addition to the maze procedure. One patient (1.3%) died 10 days after undergoing a combined maze procedure and Morrow procedure for the management of chronic atrial fibrillation and hypertrophic obstructive cardiomyopathy. Postoperative atrial pacemakers were required in 40%: 26% for preoperative sick sinus syndrome and 6% for iatrogenic injury of the sinus node, and 8% had pacemakers in place preoperatively. As of December 31, 1992, 65 patients had been followed up for at least 3 months after operation (range, 3 to 63 months). The maze procedure cured atrial fibrillation, restored atrioventricular synchrony, and preserved atrial transport function in 64 of 65 patients (98%). The procedure has been curative without the need for medications in 58 of 65 patients (89%) and with the need for medications in 6 of 65 (9%), with medications failing in only 1 of the 65 patients (2%). The results support the maze procedure as the treatment of choice in patients with medically refractory symptomatic atrial fibrillation.     

Retrospective study of auricular fibrillation of recent onset in a hospital emergency service: frequency, clinical presentation, and predictive factors of early conversion to sinus rhythm

AIM: To evaluate the proportion of emergencies due to recent-onset atrial fibrillation (AF), its clinical characteristics and in-hospital follow-up. The clinical predictors of conversion to sinus rhythm within the first 24 hours were analyzed. PATIENTS AND METHODS: 34,445 consecutive reports from patients presenting themselves at the emergency room of a community hospital during 15 months were retrospectively studied. The clinical reports of all patients (n = 186) with symptoms of recent onset AF (< 15 days) were reviewed. RESULTS: Hypertension (n = 77.41%) and lone AF (52 patients, 28%) were the most common etiologies. Forty seven patients (25%) presented with heart failure and the onset time was > 24 hours in 77 cases (41%). Conversion to sinus rhythm was observed in 71 out of 166 patients with at least 24 hours of follow-up (42.8%). Age < 60 years, the absence of cardiac disease, a NYHA functional class I, the absence of heart failure at the emergency room and the time from onset < 24 hours were significantly associated with conversion to sinus rhythm. The last two variables were selected as independent predictors by logistic regression analysis (sensitivity: 80%, specificity: 68%). CONCLUSIONS: We conclude that recent-onset AF represents 0.54% of all the hospital emergencies. The time from onset and the presence of heart failure predict the probability of conversion to sinus rhythm within the first 24 hours.     

Cost-effectiveness of therapies for patients with nonvalvular atrial fibrillation

BACKGROUND: The most appropriate treatment(s) for patients with atrial fibrillation remains uncertain. OBJECTIVE: To examine the cost-effectiveness of anti-thrombotic and antiarrhythmic treatment strategies for atrial fibrillation. METHODS: We performed decision and cost-effectiveness analyses using a Markov state transition model. We gathered data from the English-language literature using MEDLINE searches and bibliographies from selected articles. We obtained financial data from nationwide physician-fee references, a medical center's cost accounting system, and one of New England's larger managed care organizations. We examined strategies that included combinations of cardioversion, antiarrhythmic therapy with quinidine, sotalol hydrochloride, or amiodarone, and anticoagulant or antiplatelet therapy. RESULTS: For a 65-year-old man with nonvalvular atrial fibrillation, any intervention results in a significant gain in quality-adjusted life years (QALYs) compared with no specific therapy. Use of aspirin results in the largest incremental gain (1.2 QALYs). Cardioversion followed by the use of amiodarone and warfarin together is the most effective strategy, yielding a gain of 2.3 QALYs compared with no specific therapy. The marginal cost-effectiveness ratios of cardioversion followed by aspirin, with or without amiodarone, are $33800 per QALY and $10800 per QALY, respectively. Cardioversion followed by amiodarone and warfarin has a marginal cost-effectiveness ratio of $92400 per QALY compared with amiodarone and aspirin. Strategies that include cardioversion followed by either quinidine or sotalol are both more expensive and less effective than competing strategies. CONCLUSIONS: Cardioversion of patients with nonvalvular atrial fibrillation followed by the use of aspirin alone or with amiodarone has a reasonable marginal cost-effectiveness ratio. While cardioversion followed by the use of amiodarone and warfarin results in the greatest gain in quality-adjusted life expectancy, it is expensive (ie, has a high marginal cost-effectiveness ratio) compared with aspirin and amiodarone. Finally, for patients who are bothered little by symptoms of atrial fibrillation, cardioversion followed by either aspirin or warfarin without subsequent antiarrhythmic therapy is the treatment of choice.     

Efficacy of serial electrical cardioversion therapy in patients with chronic atrial fibrillation after valve replacement and implications for surgery to cure atrial fibrillation

In April 1993, a 51-year-old woman had a fever, and an infiltrative shadow was seen in the left upper lobe on a chest X-ray film. Repeated sputum cultures were positive for Mycobacterium avium complex. She underwent antituberculosis therapy consisting of pyrazinamide, ofloxacin, and streptomycin. Her symptom disappeared and the abnormal shadow resolved. In January 1994, she was admitted to the hospital because of bloody sputum and abnormal chest X-ray findings consisting of a left hilar mass and atelectasis of the left upper lobe. Bronchoscopy revealed multiple polypoid lesions without necrosis in the left upper-lobe bronchus. Histological examination showed that the tumor consisted of an aggregation of lymphocytes and plasma cells, and was positive for Ziehl-Neelsen stain. The acid-fast bacillus was identified as Mycobacterium avium by the DNA probe method. Anti-tuberculosis treatment was given: rifampicin, isoniazid, sparfloxacin, and clarithromycin. Three months later, the atelectasis and the polypoid mass in the left upper-lobe bronchus had disappeared. We believe that the polypoid lesions in the left upper-lobe bronchus were due to infection by Mycobacterium avium. The patient was HIV-negative and immunocompetent. Such endobronchial lesions caused by Mycobacterium avium are rare in HIV-negative hosts.