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

Antiarrhythmic drugs may aggravate or induce ventricular arrhythmia. The induction of a supraventricular tachycardia or its facilitation has rarely been reported. The purpose of the study was to know whether the potential for supraventricular proarrhythmic effect of a class Ia intravenous antiarrhythmic drug can be exposed during electrophysiologic study. Ajmaline was chosen because of its short duration of action. The protocol of the study consisted of an electrophysiological study and programmed atrial stimulation using 1 and 2 extrastimuli on driven rhythm and atrial pacing up to second-degree atrioventricular block. Then 1 mg/kg of ajmaline was injected and atrial pacing was performed 3 minutes after its injection. Supraventricular proarrhythmic effect of ajmaline was defined as the spontaneous occurrence of a supraventricular tachycardia or the facilitation of its induction. Seventy patients among 1955 presented a proarrhythmic effect: 63 developed a supraventricular tachyarrhythmia (atrial flutter, fibrillation, tachycardia) and 7 an atrioventricular reentrant tachycardia, either spontaneously (n = 23) or during atrial pacing (n = 47). Risk factors were identified in most patients: old age, underlying heart disease, history of spontaneous supraventricular tachycardia and/or induction of a supraventricular tachycardia by 2 extrastimuli on driven rhythm in the control state (34 patients), sinus node dysfunction (22 patients). Compared with patients without proarrhythmic supraventricular effect only the history of spontaneous supraventricular tachycardia and the existence of a sinus node dysfunction were significantly more frequent (P less than 0.05) in patients with proarrhythmic effect of ajmaline. In conclusion, the supraventricular proarrhythmic effect of intravenous ajmaline exists and is related both to the electrophysiologic characteristics of the drug and to the arrhythmia substrate. The results indicate that a supraventricular tachyarrhythmia may be induced by a class I antiarrhythmic drug.
 ...
PMID:Provocation of supraventricular tachycardias by an intravenous class I antiarrhythmic drug. 173 70

Fetal echocardiographic examination was performed on 945 pregnant women (normal pregnancy: 291, high risk pregnancy: 654) since 1980. Of these, 39 fetuses (4.1%) were diagnosed as having cardiac arrhythmia. Fifteen fetuses had bradycardia, 7 tachycardia and 17 had an ectopic beat. These had been followed from 1 day to 8 years (mean 1 year and 6 months) soon after birth. Of the 15 cases with bradycardia (complete AV block; 8, 2:1 AV block; 3 and sinus bradycardia; 4), four resulted in an intrauterine fetal death, one was terminated and 5 died soon after birth. The remaining 5 cases are alive and 3 of these 5 have received an implanted pacemaker. Of these 15 cases with bradycardia 7 were associated with congenital heart disease, 6 of which died. Seven cases had tachycardia (supraventricular tachycardia: 3 and atrial flutter with 2:1 AV block: 3). Transplacental antiarrhythmic drug (digoxin and/or verapamil) administration was instituted in 5 cases and a conversion of the arrhythmia was achieved in 4. Paroxysmal tachycardia still remained after delivery in the other 3 cases. Two cases with supraventricular tachycardia (one of them with WPW syndrome type B) were resolved. One case has had persistent chaotic atrial rhythm for 7 years after birth. Of the 17 with an ectopic beat, 11 cases were diagnosed to have a supraventricular ectopic beat and 6 cases with a ventricular ectopic beat. A remaining arrhythmia was observed in 10 cases after delivery but all of these were resolved within 3 months after birth. Fetal tachycardia had relatively favorable prognosis because usually the intrauterine treatment was effective. However, fetal bradycardia had poor prognosis and further investigations to establish more effective treatments are essential.
 ...
PMID:Fetal arrhythmias; intrauterine diagnosis and treatment. 184 Nov 76

The purpose of this study was to examine the time course and evaluate the clinical significance of marked left axis deviation (LAD) in airline pilots. The study group consisted of 30 Japan Airlines' pilots with marked LAD, identified from a group of 1,700 who are now 35 years of age or older. The mean age at examination was 48.5 +/- 5.7 years [corrected] and the mean observation period was 22.6 +/- 5.6 years [corrected]. The prevalence rate of marked LAD was 1.8%. In 20%, the axis remained unchanged, and in 70%, LAD progressed either gradually or suddenly. All subjects were examined by exercise testing and 26 had echocardiograms. Two pilots (6.7%) were found to have organic heart disease (hypertension), which was much lower than the rate reported previously. In these individuals, the onset of marked LAD was noted more than 10 years before hypertension was detected. No progression to complete left bundle branch block, nor any form of AV block, was observed among these subjects. No cardiac events or death occurred during the study period.
 ...
PMID:Time course and clinical significance of marked left axis deviation in airline pilots. 189 6

We followed 37 patients with myotonic dystrophy for a mean of 6 years. Two developed atrial flutter or fibrillation, 6 developed a new bundle branch block, 1 developed complete heart block requiring a pacemaker, and another with progressive 1st-degree heart block and a widening QRS interval had a sudden death. Most patients had predictable, gradually progressive disease of their cardiac conduction system. We recommend that patients with progressive atrioventricular block or widening QRS interval due to myotonic heart disease have yearly ECGs and be questioned about syncope or presyncope to determine the need for a cardiac pacemaker.
 ...
PMID:Myotonic heart disease: a clinical follow-up. 154 47

Digoxin excess can produce characteristic bradyarrhythmias, tachyarrhythmias, and hyperkalemia. The bradyarrhythmias, which consist of disturbances in conduction and block at the level of the atrioventricular and sinus nodes, are mediated by a direct and vagotonic effect. The vagotonic effect of excess digoxin may also result in a marked slowing of the sinus rate in the setting of severe toxicity. Digoxin increases automatic and triggered electrical activity in atrial muscle, His-Purkinje system, and ventricular muscle, which predisposes to tachycardias. Many of the tachyarrhythmias are relatively specific for the toxic effects of digoxin. Atrial tachycardias with variable atrioventricular block, accelerated junctional rhythms (especially in the setting of atrial fibrillation), and fascicular tachycardias are characteristic digoxin toxic rhythms. Digoxin-specific antibody fragments should be considered the treatment of choice for any digoxin toxic arrhythmia associated with hemodynamic compromise or the threat of hemodynamic compromise. Hyperkalemia, when due to acute severe digoxin toxicity, is also an appropriate indication for digoxin-specific Fab fragment therapy. When assessing the risk:benefit ratio for using digoxin-specific Fab fragment therapy, one needs to determine, in addition to the electrocardiographic manifestations and patient's hemodynamic status (1) the severity of toxicity, as indexed by the amount ingested and/or the serum digoxin concentration; (2) the expected time course for reversal of toxicity, which is usually determined by the status of renal function; (3) the need for digoxin to provide ventricular rate control or improved ventricular contractility and therapeutic alternatives to digoxin; (4) the presence of a strong allergy history; (5) the presence of such factors as increased age and severity of heart disease that may predispose to digoxin toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Which cardiac disturbances should be treated with digoxin immune Fab (ovine) antibody? 199 18

Catheter electrical ablation using a relatively low level of energy--40 to 100 joules--was attempted in 12 consecutive patients with drug-refractory sustained ventricular tachycardia (VT). They had 19 monomorphic VTs, and ischemic heart disease was found as the underlying heart disease in one, nonischemic heart disease was found in nine, and no structural heart disease was seen in two patients. Electrical discharge was delivered at the site of the earliest endocardial activation in 17 VTs, and at the slow conduction area in two VTs. Among 19 VTs in 12 patients, 12 VTs (63%) in seven patients (58%) were successfully ablated and became noninducible during electrophysiologic study. There were no major complications, but transient atrioventricular block occurred in one patient and transient friction rub occurred in another. Delivered electrical energy and the time interval between the local electrogram and the surface QRS did not correlate with the clinical outcome of the procedure. However, "excellent" pace-mapped QRS morphology was obtained from the site of earliest activation or from the slow conduction area in 9 of 12 VTs in the successful cases but in only one of seven VTs in the unsuccessful cases. Low-energy catheter electrical ablation seems to be a satisfactory therapeutic procedure compared with the conventional method that uses an energy level of 200 joules or higher.
 ...
PMID:Low-energy catheter electrical ablation for sustained ventricular tachycardia. 206 66

Histopathologic findings of endomyocardial biopsy in 23 pediatric patients with arrhythmias or conduction disturbance were analyzed. ECG abnormalities consisted of atrioventricular block (AVB) in 11, ventricular arrhythmia including premature ventricular contractions (PVC) and ventricular tachycardia in 7, sick sinus syndrome (SSS) in 3, and bundle branch block in 2 cases. Biopsy specimens were obtained from the right ventricle in all cases and, additionally, from the right atrium in SSS cases. Biopsy revealed significant pathology in 19 cases (83%). Advanced histologic changes, including myocyte hypertrophy, disarrangement of muscle bundles, and interstitial fibrosis with or without myocyte degeneration, were observed in 7/11 AVB cases and 1/6 PVC cases. SSS cases showed interstitial fibrosis with disarrangement of muscle bundles in the right atrium, but no significant pathologic changes were seen in the right ventricle. There was no clinical evidence of hypertrophic or dilated cardiomyopathy, cardiac defects, or other heart disease in these patients. It is suggested that these cases may fall under the arrhythmia-conduction disturbance type of cardiomyopathy.
 ...
PMID:Histopathologic findings of endomyocardial biopsies in pediatric patients with arrhythmias or conduction disturbances. 209 8

The use of pacemakers has been a major advance in the treatment of different forms of bradycardias and tachyarrhythmias. The main objectives for cardiac pacing in heart block are to improve the chances of survival and to prevent disabling symptoms, especially Stokes-Adams attacks. The long-term follow-up results of cardiac pacing are affected by different factors, in particular age and underlying heart disease; major technical aspects include pulse generator, lead and electrode longevity, and the pacing mode (VVI, atrioventricular sequential pacing, rate response stimulation, etc.). - Sinoatrial dysfunction is a relatively benign condition. Hence, pacing should probably not be adopted as a routine measure but should be reserved for patients with clinical (troublesome) symptoms. Based on earlier studies it can be concluded that patients with complete heart block and second degree atrioventricular block (Mobitz Type II) should be treated with pacemakers from the prognostic point of view. During chronic rate-responsive pacing improvement of exercise capacity can be expected in patients with sinus node disease and after His-bundle ablation. In patients with complete AV-block or bradycardia rate-responsive pacing can increase exercise tolerance and improve clinical symptoms as well. The automatic implantable cardioverter/defibrillator prevents sudden death over a long-term follow-up period in a high risk group of patients suffering from life-threatening ventricular tachyarrhythmias.
 ...
PMID:[Long-term follow-up of pacemaker therapy]. 218 Feb 29

These findings permit the following conclusions on cardiac changes induced by high-performance sports and high levels of training. Sinus bradycardia and AV block can frequently be observed in athletes, but they do not require attention as long as they are asymptomatic or do not produce pauses exceeding 4 seconds. Persistent rather than transient second-degree AV block or Mobitz second- or third-degree AV block is an extremely unusual finding even in athletes and should be considered a sign of organic lesions until proved otherwise. Supraventricular and AV node ectopic beats are not more frequent in athletes than in the general population except for atrial fibrillation. WPW syndrome is of particular importance, since rapid conduction to the ventricle via the accessory AV pathway is possible, especially if there is a tendency toward atrial fibrillation. Likewise caution is required in athletes with hypertrophic cardiomyopathy. Here hemodynamic deterioration must be anticipated with the occurrence of supraventricular tachycardia. Simple ventricular arrhythmias occur among athletes with the same frequency as in the general population, but they usually disappear with exercise. The occurrence of complex ventricular forms of arrhythmia should always prompt cardiologic examination in search of underlying cardiac disease, particularly hypertrophic or dilated cardiomyopathy. The presence of ventricular arrhythmias without evidence of underlying heart disease does not indicate a special or increased risk of sudden cardiac death. A higher incidence of right and/or left ventricular hypertrophy, exercise-reversible ST elevation, and exercise-reversible changes in T waves (T negativity, sharp and/or excessive T waves) can be considered physiologic changes in the ECGs of athletes. These changes correlate closely with the type of sports activity and degree of training and are reversible when the activity is stopped. Horizontal ST segment depression are by contrast very rare in athletes and should always be clarified by cardiologic examination. Exercise-induced sudden cardiac death in athletes is unusual without preexisting heart disease. The cause of sudden cardiac death among athletes less than 40 years of age can be predominantely ascribed to congenital heart diseases (such as hypertrophic cardiomyopathy or coronary anomalies). In athletes more than 40 years of age and with increasing age, coronary heart disease is the most frequent autopsy finding. A corresponding risk stratification should take these partial dangers into account.
 ...
PMID:ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance. 219 78

The long-term follow-up study (41 +/- 23 months) of 47 patients undergoing direct current ablation because of drug-resistant supraventricular arrhythmias is reported. Significant early complications occurred in four patients and included hypotension, pericarditis, nonsustained polymorphic ventricular tachycardia and one sudden death. In 42 patients (86%), complete atrioventricular (AV) block was initially achieved. During the follow-up period, AV conduction resumed in 2 of these 42 patients. Of the seven patients in whom ablation was unsuccessful, two developed late complete AV block and three had symptomatic improvement. An improved activity level was reported among 83% of the patients with successful ablation. Health care utilization manifest as the number of hospital admissions per year before and after ablation decreased significantly after ablation (2.4 +/- 2.0 versus 0.3 +/- 0.5, p less than 0.001). Echocardiographic evaluation in five patients with a depressed left ventricular ejection fraction (27 +/- 7%) before ablation showed a significant increase (45 +/- 14%, p less than 0.05) after an average follow-up period of 31 months. New onset of congestive heart failure occurred after ablation in four patients, of whom two had no structural heart disease. The total mortality rate, including the one patient with sudden death, was 17% and was significantly higher among patients with underlying structural heart disease. Transcatheter direct current ablation is an effective treatment in patients with drug-resistant supraventricular tachycardia, providing a beneficial long-term outcome including an improved quality of life and a decrease in health care utilization.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Long-term follow-up of patients after transcatheter direct current ablation of the atrioventricular junction. 222 1


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>