Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 70-year-old male is described who suffered from daily episodes of supraventricular tachycardia that was refractory to oral medical treatment since adolescence. Electrocardiographical and electrophysiological evaluation confirmed atrioventricular nodal re-entrant tachycardia (AVNRT). This arrhythmia commonly occurs in patients without concomitant heart disease. However, in this patient a variant form of the scimitar syndrome was found by coincidence at the age of 56 years. This report describes (1) the variant form of the scimitar syndrome, (2) the coexistence of AVNRT in scimitar syndrome, and (3) the feasibility of radiofrequency catheter ablation of AVNRT in the presence of this congenital anomaly.
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PMID:Radiofrequency catheter ablation of AV nodal re-entrant tachycardia in scimitar syndrome. 907 59

Development of asymmetry along the left-right axis is a critical step in the formation of the vertebrate body plan. Disruptions of normal left-right patterning are associated with abnormalities of multiple organ systems, including significant congenital heart disease. The mouse nodal gene, and its homologues in chick and Xenopus, are among the first genes known to be asymmetrically expressed along the left-right axis before the development of organ asymmetry. Alterations in the expression pattern of mouse nodal and the chick homologue (cNR-1) have been associated with defects in the development of left-right asymmetry and cardiac looping (Levin, M., Johnson, R. L., Stern, C. D., Kuehn, M. and Tabin, C. (1995) Cell 82, 803-814; Collignon, J., Varlet, I. and Robertson, E. J. (1996) Nature 381, 155-158; Lowe, L. A., Supp, D. M., Sampath, K., Yokoyama, T., Wright, C. V. E., Potter, S. S., Overbeek, P. and Kuehn, M. R. (1996) Nature 381, 158-161). Here, we show that the normal expression patterns of the Xenopus nodal-related gene (Xnr-1) are variable in a large population of embryos and that Xnr-1 expression is altered by treatments that perturb normal left-right development. The incidence of abnormal Xnr-1 expression patterns correlates well with cardiac reversal rates in both control and experimentally treated Xenopus embryos. Furthermore, dorsal midline structures, including notochord and/or hypochord and neural floorplate, regulate Xnr-1 expression prior to the specification of cardiac left-right orientation by repression of Xnr-1 expression in the right lateral plate mesoderm during closure of the neural tube. The correlation of Xnr-1 expression and orientation of cardiac looping suggests that Xnr-1 is a component of the left-right signaling pathway required for the specification of cardiac orientation in Xenopus, and that dorsal midline structures normally act to repress the signaling pathway on the right side of the embryo.
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PMID:Left-right asymmetry of a nodal-related gene is regulated by dorsoanterior midline structures during Xenopus development. 910 63

Atrial fibrillation is the commonest sustained cardiac arrhythmia. Its incidence increases with age and in association with organic heart disease, in particular valvular heart disease, left ventricular dysfunction and in association with thyrotoxicosis and alcohol excess. Atrial fibrillation may present as paroxysms of self-terminating arrhythmia or as a sustained arrhythmia. In the former instance, management is directed towards suppression of paroxysms and will commonly involve class 1C, class 2 or class 3 agents. If atrial fibrillation is sustained, a decision as to the desirability of cardioversion must be made. If this can be achieved successfully, particularly if the episode was of brief duration and associated with a reversible cause, sinus rhythm may be preserved without further antiarrhythmic therapy. Otherwise prophylactic therapy as used for paroxysmal atrial fibrillation is appropriate. In patients who fail to respond to cardioversion, or in those with advanced organic heart disease, long-standing atrial fibrillation or marked dilatation of the left atrium in which case cardioversion is unlikely to be successful, the principal therapeutic strategy is to control ventricular rate. Classically, digoxin is used for this purpose. Additional agents which will slow the ventricular rates, such as beta-blockers, amiodarone or calcium channel antagonists (verapamil or diltiazem), may be necessary if the ventricular rate remains uncontrolled and continues to produce severe symptoms. In the event of failure of medical therapy to control ventricular rate, atrioventricular nodal modification or ablation may be appropriate.
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PMID:Using the right drug. A treatment algorithm for atrial fibrillation. 915 73

The purposes of this study were to describe: clinical symptoms in a sample of consecutive patients with supraventricular tachycardia (SVT); incidence of sudden death, syncope, and other disabling symptoms; whether these symptoms differ by tachycardia mechanism; and to identify predictor variables of syncope in patients with SVT. Data were collected from chart reviews of 167 consecutive patients with SVT admitted for radiofrequency ablation. Three patients (2%) had nonlethal cardiac arrest, and a total of 16% (26 of 183) received at least 1 external direct-current shock for arrhythmia management. Twenty percent of subjects (33 of 167) reported at least 1 episode of syncope which was preceded by palpitations. The most frequent symptoms were: palpitations (96%), dizziness (75%), and shortness of breath (47%). We found atrioventricular nodal reentrant tachycardia (AVNRT) in 64 patients, atrioventricular-reciprocating tachycardia (AVRT) in 59, atrial tachycardia in 22, and atrial flutter in 22. The symptom profiles of patients with AVNRT, AVRT, and atrial tachycardia were very similar, but differed significantly (p <0.05) from those reported in the atrial flutter group. Multivariate analysis showed that heart rate > or = 170 beats/min was the only independent risk factor for syncope. Chi-square analysis demonstrated that SVT patients with heart rate > or = 170 beats/min had significantly more dizziness and syncope. Thus, despite a low incidence of associated heart disease, and good left ventricular function, there was a high frequency of disabling, potentially life-threatening symptoms associated with episodes of SVT in this sample. SVT can have potentially lethal consequences, and is more disruptive than previously thought.
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PMID:Frequency of disabling symptoms in supraventricular tachycardia. 919 13

Paroxysmal atrial tachycardia with atrioventricular block usually indicates potentially dangerous overdigitalization, and serious heart disease is almost universally present. In this report, we describe a patient with a structurally normal heart who manifested spontaneously intra-atrial reentrant tachycardia with Wenckebach atrioventricular block in the absence of medications. In this patient, the longest atrial paced cycle length that induced atrioventricular nodal block was 390 ms, and the atrial cycle length during tachycardia ranged from 360 to 400 ms. The electrophysiologic study in our patient demonstrated that second-degree atrioventricular block during atrial tachycardia may occur in patients without structural heart diseases or taking any medication.
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PMID:Paroxysmal atrial tachycardia with second-degree atrioventricular block. 928 11

1/1 atrial tachycardia or "quinidine" flutter under class I antiarrhythmic drugs is a serious complication of these agents which, unfortunately, cannot be anticipated. The aim of this study was to review the cases of 11 patients who had suffered this complication of class I antiarrhythmic therapy to see if it could have been prevented. All drugs of this class were included. The 11 subjects were aged 57 to 78: 7 had no apparent underlying cardiac disease and the others had valvular (n = 1), hypertensive (n = 1) and ischaemic (n = 2) heart disease. They were treated for episodes of paroxysmal atrial fibrillation or tachycardia. In the absence of treatment, 7 patients had a short PR interval on the ECG (PR between 0.11 and 0.14 s). In the other 4, the PR interval was normal (0.16 to 0.20 s), but the P wave was widened with appearances of left atrial hypertrophy or an intra-atrial conduction defect. High amplification ECG performed in 3 patients showed continuity of atrial and ventricular depolarisation. Atrial stimulation showed excellent nodal conduction with a Wenckebach point of 200/min. The authors conclude that a short PR interval is predisposing factor to 1/1 atrial tachycardia with class I antiarrhythmics. High amplification ECG which allows identification of the end of the P wave with respect to the QRS complex could help identify subjects at risk when the P wave is widened and that, consequently, the PR interval appears to be normal.
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PMID:[Can 1/1 atrial flutter be foreseen by class I anti-arrhythmics?]. 933 57

Heart rate variability on 24-hour electrocardiographic recording was assessed in 23 patients without structural heart disease before and after 2 months of oral treatment with verapamil prescribed for paroxysmal atrioventricular nodal reentrant tachycardia. Verapamil had no significant effect on overall heart rate variability in the frequency domain, but it increased ultra low frequency power and decreased the low-frequency/high-frequency ratio, deemed to be a marker of sympathetic activity.
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PMID:Effect of verapamil on heart rate variability in subjects with normal hearts. 935 62

Closed-chest transcatheter electrical ablation (catheter ablation) has been applied to various supraventricular and ventricular tachyarrhythmias as a radical therapeutic technique since its introduction in 1982. Currently, it has become a first line therapy for supraventricular tachyarrhythmias except atrial fibrillation and uncommon types of atrial flutter. We first carried out the ablation procedure in 1991 for the treatment of ventricular tachycardia. Up to February 1997, a total of 187 patients underwent catheter ablation in our institution. The aims of this study are to demonstrate our results of catheter ablation in the early 5 years and to show the usefulness of this new curative method. Successful results were obtained in 168 of 187 patients (overall final success rate: 89.8%). The success rates of each category of tachyarrhythmias were 100/105 patients (95%) with WPW syndrome, 41/46 (89%) with atrioventricular nodal reentrant tachycardia, 7/10 (70%) with atrial flutter, 4/4 (100%) with atrial tachycardia, 2/2 (100%) with medically refractory atrial fibrillation, 13/15 (85%) with idiopathic ventricular tachycardia and 3/7 (43%) with sustained ventricular tachycardia associated with structural heart disease, respectively. Complications that required invasive treatments were observed in 3 patients (2 hemopericardium and 1 complete atrioventricular block). Our results indicate that catheter ablation is highly effective in most categories of tachyarrhythmias and can be applied safely without lethal complications.
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PMID:Curative percutaneous catheter ablation for various supraventricular and ventricular tachyarrhythmias. Results in 187 consecutive patients during the first five years. 943 76

Although pacemaker recalls are common, the optimal mechanism for risk assessment and triage of patients at risk for sudden loss of device system function is unknown. A retrospective chart review of 120 patients with factory proven failed devices was performed. Logistic regression analysis was used to determine clinical correlates of emergency room versus outpatient clinic presentation at time of device failure. Twenty-two patients (18%) presented to emergency and 98 (82%) to clinic. Sixty-three devices had no device output at the time of presentation. Multivariate logistic regression analysis revealed that antiarrhythmic drug use (odds ratio: 7.4, 95% CI: 2.0-28.0), atrioventricular nodal disease as an indication for pacing (odds ratio: 2.8, 95% CI: 1.2-3.0), and female gender (odds ratio: 2.2, 95% CI: 1.0-4.5) were the only significant correlates of emergency room presentations. Pacemaker dependency (escape heart rate < 40 beats/min) did not correlate with location of presentation even though no device output at the time of presentation was associated with emergency room presentation (odds ratio: 2.5, 95% CI: 1.1-5.8). Neither the presence of structural heart disease nor symptoms at the time of device implantation (syncope or presyncope) were correlated with location of presentation upon unexpected device failure. Although there were no deaths in the 120 failed devices studied, there were 26 deaths in the total group of 227 patients with recalled devices that could not be studied. Antiarrhythmic drug use, electrocardiographic pacing indication, and female gender may be more sensitive predictors of emergency room presentation and significant symptoms in the event of unanticipated pacemaker failure. The inability of any retrospective analysis to accurately assess mortality in the setting of pacemaker system failure underscores the need for prospective databases in recall situations.
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PMID:When pacemakers fail: an analysis of clinical presentation and risk in 120 patients with failed devices. 947 52

Inappropriate sinus tachycardia and atrial arrhythmias have been reported after radiofrequency ablation. Previous studies have suggested that cardiac denervation is a possible explanation for these rhythm disturbances. The aim of this study was to investigate possible alterations in autonomic innervation of the heart after ablation using the techniques of heart rate variability (HRV) analysis and metaiodobenzylguanidine (I-123 MIBG) scintigraphy. The subjects of this study were 30 consecutive patients aged 25 to 40 years, without structural heart disease, who underwent radiofrequency ablation of atrioventricular nodal slow pathways, and posteroseptal and left lateral accessory pathways because of symptomatic recurrent reentrant tachycardias. Time and frequency domain analysis of HRV after ablation revealed a significant reduction in the indexes of the mean of all 5-minute standard deviation of RR intervals (p = 0.042), low frequency (p = 0.0005), and total frequency (p = 0.008) compared with preablation values in the group of patients who underwent atrioventricular nodal slow pathway ablation. Patients who underwent ablation of a posteroseptal accessory pathway also had significant attenuation of the indexes of standard deviation about the mean RR interval (p = 0.03), standard deviation of 5-minute mean RR intervals (p = 0.006), and low-frequency (p <0.0001), and high-frequency (p <0.0001) components. Significant I-123 MIBG map defects, indicating efferent cardiac sympathetic denervation, were also found in the same groups of patients: atrioventricular nodal group (p = 0.0024), posteroseptal accessory pathway group (p = 0.0007). None of the above changes in HRV and 123-I MIBG scintigraphy were seen in patients who underwent ablation of left lateral accessory pathways. We conclude that radiofrequency ablation in the anterior, mid-, and posterior regions of the low intraatrial septum may disrupt sympathetic fibers located in these regions, causing cardiac sympathetic denervation. The density of these fibers appear to be less along the left atrioventricular groove.
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PMID:Cardiac denervation after radiofrequency ablation of supraventricular tachycardias. 952 82


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