Sleep-disordered breathing and chronic atrial fibrillation.

BACKGROUND: Little has been known about the prevalence of sleep apnea in patients with atrial fibrillation (AF). Studies have suggested that the prevalence of AF is increasing in patients with sleep-disordered breathing. We hypothesize that the prevalence of OSA is higher in chronic persistent and permanent AF patients than a sub-sample of the general population without this arrhythmic disorder. OBJECTIVE: Evaluate the frequency of Obstructive Sleep Apnea in a sample of chronic AF compared to a sub-sample of the general population. METHODS: Fifty-two chronic AF patients aged (60.5 +/- 9.5, 33 males) and 32 control (aged 57.3 +/- 9.6, 15 males). All subjects were evaluated by a staff cardiologist for the presence of medical conditions and were referred for polysomnography. The differences between groups were analyzed by ANOVA for continuous variables, and by the Chi-square test for dichotomous variables. Statistical significance was established by alpha=0.05. RESULTS: There were no differences in age, gender, BMI, sedentarism, presence of hypertension, type 2 diabetes mellitus, abdominal circumference, systolic and diastolic blood pressure, and sleepiness scoring between groups. Despite similar BMI, AF patients had a higher neck circumference compared to control group (39.9cm versus 37.7cm, p=0.01) and the AF group showed higher percentage time of stage 1 NREM sleep (6.4% versus 3.9%, p=0.03). Considering a cut-off value for AHI >= 10 per hour of sleep, the AF group had a higher frequency of OSA compared to the control group (81.6% versus 60%, p=0.03). All the oxygen saturation parameters were significantly worse in the AF group, which had lower SaO(2) nadir (81.9% versus 85.3%, p=0.01) and mean SaO(2) (93.4% versus 94.3%, p=0.02), and a longer period of time below 90% (26.4min versus 6.7min, p=0.05). CONCLUSION: Sleep-disordered breathing is more frequent in chronic persistent and permanent AF patients than in age-matched community dwelling subjects.

Atrial fibrillation after vardenafil therapy.

Vardenafil is a new oral phosphodiesterase inhibitor used for erectile dysfunction. We report a case admitted with a first-detected, symptomatic paroxysmal atrial fibrillation in a healthy patient after self-medication with vardenafil.

Hydrochlorothiazide abolishes the anti-atherosclerotic effect of quinapril.

1. Antihypertensive treatment has been demonstrated to result in persistent reductions in morbidity and mortality due to stroke. However, the coronary risk attributable to hypertension has been only partially reversed. We hypothesized that diuretics could have unfavourable effects on atherosclerosis. 2. New Zealand rabbits were fed a 0.5% cholesterol-enriched diet for 12 weeks, followed by a 0.1% cholesterol diet for another 12 weeks. During the last 12 week period, 40 animals were randomly assigned to one of four groups: (i) group I was the control group; (ii) group II received hydrochlorothiazide (10 mg/day); (iii) group III received quinapril (30 mg/day); and (iv) group IV was treated with hydrochlorothiazide (10 mg/day) plus quinapril (30 mg/day). 3. The treatments did not affect either the lipid profile or serum electrolytes and oxidative stress. However, endothelium-dependent vasorelaxation in isolated aortic rings was significantly improved with quinapril (group III) treatment (P < 0.001 vs other groups). In addition, therapy with quinapril promoted a significant reduction in atherosclerosis (intima area, intima/media ratio and perimeter of vessel with plaque; P < 0.05 vs other groups), as well as in cholesterol content of the aorta (P < 0.05 vs groups II and IV). 4. In conclusion, hydrochlorothiazide did not modify atherosclerosis and, when added to quinapril treatment, impaired the anti-atherosclerotic effect seen with quinapril alone.

Kinetic disposition of (+)-S- and (-)-R-sotalol enantiomers in cardiac patients with tachyarrhythmias using an improved HPLC-fluorescence stereoselective method.

Since the enantioselective pharmacokinetic profiles of R,S-sotalol in cardiac patients are controversial, the present investigation aimed to study the kinetic disposition of sotalol enantiomers in patients with tachycardia. Thirteen cardiac patients, who gave their written consent, were included (6F/7M; 53 +/- 12 yrs, 66 +/- 13 kg, 163 +/- 8 cm height). They had tachycardia, normal renal function and had been chronically treated with tablets of sotalol 160 mg b.i.d. The patients were submitted to blood samples collection at zero, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10 and 12 h after drug administration. The quantitation of sotalol enantiomers were performed by a stereoselective HPLC method with fluorescence detection previously published. A one open compartment model was applied and the main pharmacokinetic parameters obtained for R-/S-sotalol were, respectively (Mean +/- SD): CSSMAX = 1007 +/- 307/1040 +/- 340 ng/mL; TMAX = 1.82 +/- 0.6/1.83 +/- 0.6 h; AUCSST = 6959 +/- 2153/7388 +/- 2563 ng.h/mL; CISSr/F = 2.7 +/- 1.2/2.5 +/- 1.2 mL/min/kg and VdSS/F = 1.9 +/- 0.9/2.0 +/- 1.0 L/kg. The pharmacokinetic parameters of R,S-sotalol were within the published range and the kinetic parameters for the isomers were grouped as two independent samples and statistically compared. In conclusion, stereoselective pharmacokinetic for sotalol was not observed in cardiac arrhythmic patients, i.e., both R- and S-sotalol enantiomers have the same pharmacokinetic profile.

Treatment of atrial fibrillation with radiofrequency ablation and simultaneous multipolar mapping of the pulmonary veins.

OBJECTIVE: To demonstrate the feasibility and safety of simultaneous catheterization and mapping of the 4 pulmonary veins for ablation of atrial fibrillation. METHODS: Ten patients, 8 with paroxysmal atrial fibrillation and 2 with persistent atrial fibrillation, refractory to at least 2 antiarrhythmic drugs and without structural cardiopathy, were consecutively studied. Through the transseptal insertion of 2 long sheaths, 4 pulmonary veins were simultaneously catheterized with octapolar microcatheters. After identification of arrhythmogenic foci radiofrequency was applied under angiographic or ultrasonographic control. RESULTS: During 17 procedures, 40 pulmonary veins were mapped, 16 of which had local ectopic activity, related or not with the triggering of atrial fibrillation paroxysms. At the end of each procedure, suppression of arrhythmias was obtained in 8 patients, and elimination of pulmonary vein potentials was accomplished in 4. During the clinical follow-up of 9.6+/-3 months, 7 patients remained in sinus rhythm, 5 of whom were using antiarrhythmic drugs that had previously been ineffective. None of the patients had pulmonary hypertension or evidence of stenosis in the pulmonary veins. CONCLUSION: Selective and simultaneous catheterization of the 4 pulmonary veins with microcatheters for simultaneous recording of their electrical activity is a feasible and safe procedure that may help ablation of atrial fibrillation.

The impact of syncope during clinical presentation of sustained ventricular tachycardia on total and cardiac mortality in patients with chronic Chagasic heart disease.

OBJECTIVE: To assess the impact of syncope during sustained ventricular tachycardia on total and cardiac mortality in patients with chronic chagasic heart disease. METHODS: We assessed 78 patients with sustained ventricular tachycardia and chronic Chagas' heart disease. The mean age was 53+/-10 years, 45 were males, and the mean ejection fraction was 49.6+/-13%. The patients were divided into 2 groups according to the presence (GI=45) or absence (GII=33) of syncope during sustained ventricular tachycardia. RESULTS: After a mean follow-up of 49 months, total mortality was 35% (28 deaths), 22 deaths having a cardiac cause (78.6%). No difference was observed in total (33.3% x 39.4%) and cardiac (26.7% x 30.3%) mortality, or in nonfatal sustained ventricular tachycardia between GI and GII patients (57.6% x 54.4%, respectively). However, the presence of syncope during recurrences was significantly greater in those patients who had had the symptom from the beginning (65.4% x 18.1%, p<0.01). CONCLUSION: Syncope during the presentation of sustained ventricular tachycardia is not associated with an increase in total or cardiac mortality in patients with chronic Chagas' heart disease. However, syncope during the recurrence ventricular tachycardia is greater in patients experiencing syncope in the first episode, of sustained ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia. An important diagnosis in children with syncope and normal heart.

Syncope in children is primarily related to vagal hyperreactivity, but ventricular tachycardia (VT) way rarely be seen. Catecholaminergic polymorphic VT is a rare entity that can occur in children without heart disease and with a normal QT interval, which may cause syncope and sudden cardiac death. In this report, we describe the clinical features, treatment, and clinical follow-up of three children with syncope associated with physical effort or emotion and catecholaminergic polymorphic VT. Symptoms were controlled with beta-blockers, but one patient died suddenly in the fourth year of follow-up. Despite the rare occurrence, catecholaminergic polymorphic VT is an important cause of syncope and sudden death in children with no identified heart disease and normal QT interval.

An improved HPLC-fluorescence stereoselective method for analysis of (+)-S- and (-)-R-sotalol enantiomers in plasma sample.

A simplified high performance chromatographic method (HPLC) was performed for sotalol enantiomers in plasma samples for purposes of investigation of the kinetic disposition of racemic sotalol in cardiac arrhythmic patients under multiple dose and multidrug therapy regimens. After addition of NaCl:Na2CO3 (4:1) and plasma protein precipitation by acetonitrile:methanol mixture (1:1) the supernatant was evaporated. The residue containing sotalol racemate was submitted to derivatization reaction with (-)-menthylcloroformate to R(-)- and S(+)-sotalol diastereoisomers. The diastereoisomers were resolved in HPLC, by a C18 column with fluorescent detection under lexcitation = 235 nm and lemission = 310 nm. The retention times for R- and S-sotalol were 20 and 22 minutes while that of internal standard S(-)-atenolol, was 17 minutes. The detection limit for each enantiomer was 12.5 ng/mL and intra-day/inter-day coefficients of variation were less than 10% for each enantiomer within a concentration range of 200 and 2000 ng/mL. The method was appropriate for the objective proposed.

Efficacy and safety of sotalol versus quinidine for the maintenance of sinus rhythm after conversion of atrial fibrillation. SOCESP Investigators. The Cardiology Society of São Paulo.

To compare the efficacy and safety of sotalol and quinidine after conversion of atrial fibrillation (AF) of <6 months, a prospective multicenter trial enrolled 121 patients who were randomized to receive dl-sotalol (160 to 320 mg/day, 58 patients) or quinidine sulfate (600 to 800 mg/day, 63 patients). Patients with left ventricular ejection fraction of <0.40 or left atrial diameter >5.2 cm were excluded. After 6 months of follow-up, using the Kaplan-Meier method, the probabilities of success were comparable between sotalol (74%) and quinidine (68%), but recurrences occurred later with sotalol than with quinidine (69 vs 10 days, p <0.05). Four patients developed proarrhythmic events, 3 (5%) with sotalol and 1 (2%) with quinidine, which were all associated with diuretic therapy. In patients converted from recent-onset AF (< or = 72 hours), sotalol was more effective than quinidine (93% vs 64%, p = 0.01), whereas in chronic AF (> 72 hours), quinidine was more effective than sotalol (68% vs 33%, p <0.05). During recurrences, the ventricular rate was significantly reduced in patients taking sotalol (98 to 82 beats/min, p <0.05). Independent predictors of therapeutic success were recent-onset AF in the sotalol group (p <0.001) and absence of hypertension in the quinidine group (p <0.05). In conclusion, sotalol and quinidine have comparable efficacy and safety for the maintenance of sinus rhythm in the overall group. In recent-onset AF, sotalol was more effective, whereas in chronic AF, quinidine had a better result. Recurrences occurred later with sotalol when compared with quinidine. Because of proarrhythmia, these drugs should be used judiciously in patients on diuretic therapy.

Characteristics and identification of sites of chagasic ventricular tachycardia by endocardial mapping.

OBJECTIVE: To study electrophysiological characteristics that enable the identification and ablation of sites of chagasic tachycardia. METHODS: Thirty-one patients with chronic Chagas' heart disease and sustained ventricular tachycardia (SVT) underwent electrophysiological study to map and ablate that arrhythmia. Fifteen patients had hemodynamically stable SVT reproducible by programmed ventricular stimulation, 9 men and 6 women with ages ranging from 37 to 67 years and ejection fraction varying from 0.17 to 0.64. Endocardial mapping was performed during SVT in all patients. Radiofrequency (RF) current was applied to sites of presystolic activity of at least 30 ms. Entrainment was used to identify reentrant circuits. In both successful and unsuccessful sites of RF current application, electrogram and entrainment were analyzed. RESULTS: Entrainment was obtained during all mapped SVT. In 70.5% of the sites we observed concealed entrainment and ventricular tachycardia termination in the first 15 seconds of RF current application. In the unsuccessful sites, significantly earlier electrical activity was seen than in the successful ones. Concealed entrainment was significantly associated with ventricular tachycardia termination. Bystander areas were not observed. CONCLUSION: The reentrant mechanism was responsible for the genesis of all tachycardias. In 70.5% of the studied sites, the endocardial participation of the slow conducting zone of reentrant circuits was shown. Concealed entrainment was the main electrophysiological parameter associated with successful RF current application. There was no electrophysiological evidence of bystander regions in the mapped circuits of SVT.

[Catheter ablation of atrial flutter. Electrophysiological characterization of posterior and septal isthmus block]. / Ablação por cateter do flutter atrial. Caracterização eletrofisiológica da interrupção da condução pelos istmos posterior e septal.

PURPOSE: Evaluate the different types of conduction blocks obtained between inferior vena cava-tricuspid annulus (posterior isthmus) and between tricuspid annulus-coronary sinus ostium (septal isthmus) after radiofrequency (RF) catheter ablation of atrial flutter (AFL). METHODS: In 16 procedures, 14 patients (pts), 9 male, with type I AFL underwent RF ablation. Atrial activation around tricuspid annulus was performed with a 10-bipole "Halo" catheter (H1-2; H19-20). In sinus rhythm, isthmus conduction was evaluated during proximal coronary sinus (PCS) and low lateral right atrium (H1-2) pacing, before and after linear ablation. According to the wave front of impulse propagation we assessed absence of block (bidirectional conduction); incomplete block (bidirectional conduction with delay in one front of impulse propagation) and complete block (absence of conduction). The PCS/H1-2 interval was measured before and after ablation. RESULTS: Complete isthmus block was achieved in 7 (44%) and incomplete block in 4 (25%) procedures. Conduction block was not achieved in 5 procedures. At a mean follow-up of 12 months, there were no recurrences in the pts with complete block, whereas AFL recurred in the 6 pts with incomplete or no conduction block (p < 0.001). Pts with complete block had delta PCS/H1-2 interval (74.0 +/- 26.0 ms) greater than incomplete (30.5 +/- 7.5 ms) or absent block (p < 0.05). CONCLUSION: The verification of complete isthmus conduction block with atrial multipolar mapping is an effective strategy to assess electrophysiological success and absence of late recurrence in common atrial flutter ablation.

[Angiography of the coronary venous system. Use in clinical electrophysiology]. / Anatomia angiográfica do sistema venoso coronário. Aplicações em eletrofisiologia clínica.

PURPOSE: To study the angiographic anatomy of human coronary veins and the possibility of epicardial venous mapping through microelectrode catheters. METHODS: We evaluated 30 patients with sustained ventricular tachycardia using a catheter which provided occlusion of the coronary sinus ostium during venous angiography. They were 25 males, 5 females, ages ranging from 24 to 76 years (mean = 52.7). The veins were studied according to their number, caliber and distribution in the anterior and posterior wall of the left ventricle. RESULTS: Coronary sinus was catheterized in all patients. No discomfort or complication were observed. The number of veins from posterior wall of the left ventricle was 3.1 and anterior wall, 1.9, p < 0.05. The caliber of the coronary veins were: anterior interventricular vein (distal segment = 1.19 +/- 0.22 mm, middle segment = 1.65 +/- 0.35 mm), posterior interventricular vein (distal segment = 1.83 +/- 0.47 mm, middle segment = 2.00 +/- 0.52 mm), left posterior vein (distal segment = 1.45 +/- 0.25 mm, middle segment = 2.49 +/- 0.92 mm); p < 0.05. CONCLUSION: The balloon occlusion technique for coronary venous angiography is feasible and safe. The number and the caliber (distal and middle) of the veins from the posterior wall of the left ventricle were significantly greater than those from the anterior wall. Anatomic conditions for venous epicardial mapping are more adequate in the posterior wall of the left ventricle.

[Analysis of atrial fibrillation recurrence during therapy with sotalol or quinidine. Researchers of +SOCESP]. / Análise da recorrência de fibrilação atrial durante terapia com sotalol ou quinidina. Investigadores da SOCESP.

PURPOSE: To analyze the recurrences of atrial fibrillation in patients treated with sotalol or quinidine. METHODS: After conversion to sinus rhythm, 121 patients with paroxysmal atrial fibrillation were randomized to sotalol (58 patients) or quinidine (63 patients) and followed-up during 6 months. Symptoms and ventricular rates on the 12 lead electrocardiogram of the arrhythmic events were compared between the two groups. Clinical and echocardiographic characteristics were analyzed as predictors of atrial fibrillation recurrence. RESULTS: Seventeen (14%) patients relapsed into atrial fibrillation; 7 (12%) were treated with sotalol and 10 (16%) with quinidine. Recurrence occurred later in the sotalol group (median 69 days) in comparison with the quinidine group (median 10 days) (p = 0.04). Symptoms were present in 14 (82%) patients during the initial crisis and in 10 (47%) during recurrence. Recurrence was less symptomatic during antiarrhythmic therapy (p < 0.04), with no statistical differences between the two groups. Only patients treated with sotalol had ventricular rates during the recurrences lower than during initial crisis (p < 0.02). All variables failed to predict recurrence of atrial fibrillation. CONCLUSIONS: It was not possible demonstrate differences between sotalol and quinidine for the prevention of atrial fibrillation. Recurrence was less symptomatic during antiarrhythmic therapy. Patients treated with sotalol relapsed to atrial fibrillation later and had ventricular rates during recurrences significantly lower than during the initial crisis.