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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with supraventricular arrhythmias have been safely and effectively treated with flecainide. We conducted an open-label, 20-center trial to define further the safety and efficacy profile of oral flecainide in patients with supraventricular arrhythmias, including atrial tachycardias (ectopic or multifocal), atrial-ventricular tachycardias (reentrant), paroxysmal atrial fibrillation/flutter (PAF), and chronic atrial fibrillation (CAF). Our study population of 151 patients with documented supraventricular arrhythmias requiring treatment included 67 with paroxysmal supraventricular tachycardia (PSVT), 67 with PAF (symptoms < 15 days), and 17 with CAF (symptoms > of = 15 days)> The initial flecainide dose of 100 mg twice daily could be increased by 50 mg bid every 4 days to a maximum of 200 mg twice daily. Patients who were effectively treated could receive flecainide for 1 year. The study was terminated April 26, 1989, in response to interim results reported by the Cardiac Arrhythmia Suppression Trial (CAST). All patients were removed from the study by August 1989. At study termination 87% of PSVT, 73% of PAF, and 56% of CAF patients had improved symptomatically while on flecainide therapy. Eleven patients experienced cardiac adverse experiences: proarrhythmic events (3 patients), new or worsened congestive heart failure (7 patients), sinus pauses (1 patient). Cardiac side effects appeared to be more frequent in patients in the CAF group (5/17 patients), all of whom had structural heart disease. Overall, 45 (67%) PSVT, 43 (64%) PAF, and 9 (56%) CAF patients reported at least 1 noncardiac adverse experience; the most common were abnormal vision, dizziness, and headaches. One patient from the CAF group died; the death was considered to be unrelated to flecainide. Flecainide appears to be safe and effective treatment for patients with supraventricular arrhythmias of a variety of mechanisms and appears particularly effective for patients with PSVT. The efficacy is lowest and side effects most frequent in patients with CAF, as seen with other trials of antiarrhythmic medication in these patients. In the context of the CAST experience and other trials of antiarrhythmic drugs in patients with CAF, the balance of risk and benefit of therapy should be considered carefully before initiating treatment.
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PMID:Safety and utility of flecainide acetate in the routine care of patients with supraventricular tachyarrhythmias: results of a multicenter trial. The Flecainide Supraventricular Tachycardia Study Group. 860 95

Left atrial enlargement has been demonstrated to occur as a consequence of the arrhythmia in patients with chronic atrial fibrillation (AF) in the absence of organic heart disease, whereas contrasting results have been reported in patients with paroxysmal lone AF. In the present investigation the behavior of left atrial size was followed up for an average period of 30.3 months in 20 patients with paroxysmal lone AF since their first arrhythmic episode. No significant changes in left atrial size were found at the end of the follow-up period. In 65% of patients the arrhythmia recurred at least once yearly. Left atrial size at enrollment was not significantly different in these patients from those without recurrences and did not change in either group during follow-up. The results suggest that in patients with lone AF left atrial dilatation occurs only after the arrhythmia becomes chronic. Early restoration of sinus rhythm may interrupt the vicious circle leading to atrial enlargement.
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PMID:Left atrial size changes in patients with paroxysmal lone atrial fibrillation. An echocardiographic follow-up. 871 83

Although different computerized systems have been developed to localize specific patterns in electrocardiographic (ECG) signals, it is still difficult to detect T waves and measure QT intervals during atrial fibrillation. This article demonstrates the use of an auto-correlation (ECG) based system that was used to investigate the dynamicity of QT intervals related to active postural change in patients with chronic atrial fibrillation. Twenty patients (9 male, mean age 63 years) with chronic atrial fibrillation (8 idiopathic, 12 organic heart disease) were examined. Seventeen of these patients were on digoxin, but patients with other conditions potentially affecting the autonomic nervous system were not included. A 3-channel ECG was recorded digitally during active postural change from supine to standing. Data were first analyzed by the Burdick Altair system and subsequently processed using an in-house software package evaluating auto-correlations of ECG signals. An ECG channel with suitable repolarization patterns was found in 15 patients. The mean QT interval of 409.8 +/- 11.1 ms (mean +/- SE) recorded during supine position shortened to 401.9 +/- 9.89 ms during the first minute of active standing (P < 0.05) and to 394.8 +/- 10.0 ms during the second minute of active standing (P < 0.005). It did not further change during the subsequent minutes of active standing. The study shows that automatic detection of QT intervals during atrial fibrillation is possible. Although the effect of position change of the heart cannot be completely excluded, the study suggests that QT interval is changed directly by autonomic nervous mechanisms rather than indirectly via the mean heart rate.
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PMID:Changes of QT intervals associated with postural change in patients with chronic atrial fibrillation. 884 98

Dynamic Behavior of the Dispersion of Ventricular Repolarization. The aim of this study was to evaluate the circadian variation in the spatial dispersion of ventricular repolarization in continuously paced patients with congestive heart failure (CHF). Fourteen patients (10 males, 4 females, aged 65 +/- 8 years) with CHF due to dilated cardiomyopathy (DCM) and an echocardiographic ejection fraction of 28% +/- 3% were studied. All patients underwent AV junctional RF ablation and permanent pacemaker implantation for drug refractory chronic atrial fibrillation (AF). Patients were evaluated at 1 month postimplant with a three-channel 24-hour Holter monitor, using the three plane Frank orthogonal leads (X, Y, and Z), in VVI pacing mode at 70 beats/min. For each hour, the mean value of spike-T interval dispersion of the first five beats was measured. The control group consisted of 20 patients without structural heart disease, but with AF and complete AV block, continuously paced in VVI mode at 70 beats/min. The dispersion of the spike-T interval had a circadian behavior in the study population, with higher values at night and lower during the daytime. During the daytime, the mean value of spike-T interval dispersion was 39 +/- 5 ms and during the nighttime it was 45 +/- 7 ms (P = 0.003). Such a difference between day and night was not found in the control group (38 +/- 6 ms and 40 +/- 8 ms, respectively, P = NS). In the daytime period the mean value of spike-T interval dispersion of our study population was comparable to that of the control group (P = NS), while during the nighttime it was significantly higher (P = 0.0004). In conclusion, by evaluating the dispersion of ventricular repolarization in two dimensions, space and time, a circadian variation was found in paced patients with CHF due to DCM. The increased QT dispersion in these patients during the nighttime period was attributed to different effects of vagal activity in normal and abnormal myocardial areas.
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PMID:Congestive heart failure and VVI pacing mode: dynamic behavior of the dispersion of ventricular repolarization. 894 63

Between January and September 1995, 54 consecutive patients (male: 34, age: 66 +/- 10 years) with symptomatic chronic atrial fibrillation (median duration: 4.5 months) were referred for external electrical cardioversion to our hospital. Mean left atrial diameter was 49 +/- 9 mm, heart disease was apparent in 81%. All patients were under antiarrhythmic drugs (class III: 85%). In 49 patients (91%) sinus rhythm was achieved. In five patients atrial fibrillation persisted after delivery of 360 Joules. These five patients were characterized by a significantly higher body weight in comparison to patients with successful external cardioversion. All five patients underwent low energy internal cardioversion the following day: biphasic R-wave synchronous shocks were delivered through catheters positioned in the right atrium and the coronary sinus using stepwise increased energy levels. Internal cardioversion was successful in all patients resistant to external cardioversion: stable sinus rhythm was established at a mean energy level of 13 +/- 6.7 Joules. No complications were observed. During the follow-up, each patient revealed a relapse of symptomatic atrial fibrillation within 2 weeks after internal cardioversion despite antiarrhythmic therapy, whereas only 16 patients (33%) lost sinus rhythm during the same period of time after external cardioversion (p < 0.01). During a mean follow-up of 283 +/- 72 days 21 patients (43%) preserved stable sinus rhythm after external cardioversion. Internal low energy cardioversion seems to be effective and safe in conversion of chronic atrial fibrillation resistant to external cardioversion. The clinical value of this invasive, time- and material-consuming therapy seems to be limited in this setting because of the high early relapse-rate in the investigated patient population. Further clinical studies in a larger cohort of patients are necessary.
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PMID:[Initial clinical experiences with low energy internal cardioversion of chronic atrial fibrillation after unsuccessful external cardioversion]. 908 72

After cardioversion of chronic atrial fibrillation to sinus rhythm, there is a gradual increase of 56% in cardiac output over 4 weeks. The increase is caused by the gradual return and increasing strength of left atrial mechanical activity as the atrial myopathy of chronic atrial fibrillation subsides. Cardiac output decreases after cardioversion of atrial fibrillation in more than a third of patients, and the decrease may last a week. Acute pulmonary edema is uncommon; 50% of cases occur within 3 hours of cardioversion, with a mortality of 18%. The reduced cardiac performance after cardioversion most likely results from the combination of heart disease and cardiac depressant effects of anesthetic drugs used. Pulmonary and/or coronary artery emboli and the resumption of right atrial mechanical activity before left atrial mechanical activity may be additional factors in the pathogenesis of pulmonary edema after cardioversion. Anticoagulant therapy should be continued for a month or longer after cardioversion in those patients who maintain sinus rhythm to prevent thromboembolism.
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PMID:Hemodynamic changes after cardioversion of chronic atrial fibrillation. 952 Dec 33

The risk of thromboembolism after unprotected DC cardioversion for chronic atrial fibrillation is 5%. The use of transoesophageal echocardiographic guidance probably reduces this risk to around 1.3%. However, after conventional courses of anticoagulation, the risk is only 0.3 to 0.8%. Until there is further information from large randomised trials, the routine use of transoesophageal echocardiography cannot be recommended. However it should be considered in acute onset atrial fibrillation of less than 2 days duration in the presence of underlying structural heart disease or in individual patients who have previously suffered an embolic event.
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PMID:Is it safe to cardiovert atrial fibrillation without anticoagulation if the transoesophageal echocardiogram is normal? 951 Apr 82

The authors performed 451 transesophageal echocardiographic (TEE) investigations over a period of three years and four months. Atrial septal aneurysm (ASA) was found in 40 cases. Of these, protrusion of the atrial septum towards the right atrium was observed in 17 cases, whilst oscillation of the atrial septum was noted in 23 cases. ASA was associated with patent foramen ovale (PFO) in ten patients, with type II. ASD in nine patients, with other congenital heart disease in six patients, and with other organic heart disease in eight patients. In three cases either an embolus or a tumor was detected in the left atrium, whilst in four cases with ASA there were no other organic cardiac disorders found. In ten patients there was a history of cerebral embolisation. Of these two had chronic atrial fibrillation, whilst the others had sinusrhythm. Of those who had cerebral embolisation, four patients had PFO, one patient had left atrial and auricular thrombi, whilst in four patients various organic heart problems (ischemic heart disease, left ventricular hypertrophy) were detected. In one patient with ASA there was no other cardiac abnormality detected. The authors conclude that ASA, which is often associated with PFO and ASD (in 25.0% and 22.5% of their cases, respectively) is detected in around eight percent of the patients who undergo TEE. ASA particularly when associated with PFO should be considered as a potential source of cerebral emboli. Indeed, cerebral embolisation occurred in 25% of their patients with ASA. It is recommended, that patients with ASA are treated with acetyl salicylic acid, whilst in patients with ASA and PFO anticoagulant therapy is the treatment of choice. In case of cerebral embolisation, or repeated cerebral ischemic attacks, operative interventions should be considered.
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PMID:[Incidence of septal aneurysm and its clinical significance]. 955 64

In drug-resistant, poorly tolerated atrial fibrillation, atrioventricular (AV) junction catheter ablation can be proposed as the last-resort option. Technically, the procedure is easy to perform and relatively safe. Interruption of the AV conduction implies the insertion of a permanent pacemaker. In patients with chronic atrial fibrillation, a VVIR pacemaker is inserted. For those having severely symptomatic episodes of paroxysmal atrial fibrillation, DDDR mode-switching devices are more appropriate. Results are remarkable. The treatment is highly effective in controlling symptoms and improving general well-being. Exercise capacity is also increased. Left ventricular ejection fraction may increase after ablation, an effect that is mainly apparent in patients with markedly depressed myocardial function. Consumption of healthcare resources has been shown to decrease significantly in the aftermath of AV junction ablation. However, sudden-death risk has been invoked as a limiting factor for the procedure. This may be due to AV-block-related ventricular tachyarrhythmias, occurring early after ablation, whereas the reasons for late sudden deaths are somewhat more obscure. It is unclear whether such events are procedure-related or rather secondary to the underlying heart disease. Thus, AV junction ablation for refractory atrial fibrillation remains the only nonpharmacologic, alternative therapy that is performed on a routine basis. Failure of newer therapeutic approaches should further reinforce the clinical impact of this procedure in the future.
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PMID:Atrioventricular nodal ablation and pacemaker implantation in patients with atrial fibrillation. 1008 72

Although several studies demonstrated that the presence of significant mitral regurgitation was associated with reduced occurrence of thromboembolism, little data is available concerning the effect of mild mitral regurgitation on the occurrence of thromboembolic events. To evaluate the association between mild mitral regurgitation and thromboembolic events, we reviewed 232 patients' records between January 1996 and September 1997 who had nonrheumatic atrial fibrillation. There were 59 patients (25%) with mitral regurgitation > or = grade 2, 69 patients (30%) with grade 1 mitral regurgitation, and 104 patients (45%) with no mitral regurgitation. Patients with grade 1 mitral regurgitation had significantly higher prevalence of thromboembolic events (28%) than those with mitral regurgitation > or = grade 2 (8%, P=0.006) or those with no mitral regurgitation (11%, P=0.007). A history of previous thromboembolic events were compared between 173 patients with grade 1 mitral regurgitation and those with no mitral regurgitation using the logistic regression analysis adjusted for age, sex, administration of warfarin, and presence of hypertension, diabetes mellitus, structural heart disease, enlarged left atrium (> or = 40 mm), chronic atrial fibrillation, and grade 1 mitral regurgitation. Grade 1 mitral regurgitation (odds ratio=2.689, 95% confidence interval=1.039-7.189, P=0.0434) and no warfarin administration (odds ratio=0.045, 95% confidence interval=0.002-0.242, P=0.0036) were significantly associated with the history of thromboembolic events. The presence of mild mitral regurgitation in nonrheumatic atrial fibrillation was associated with higher prevalence of thromboembolic events.
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PMID:Mild mitral regurgitation was associated with increased prevalence of thromboembolic events in patients with nonrheumatic atrial fibrillation. 1071 32


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