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

In recent years calcium channel blockers have emerged as a new class of antiarrhythmic agents for the control of certain supraventricular and ventricular arrhythmias. Electrophysiologically, they are heterogeneous but their main action is mediated through a depressant effect on the slow calcium channel in cardiac muscle. In isolated muscle, their actions are modulated by their reflex actions and by their interaction with the autonomic nervous system due to the nonocompetitive adrenergic blocking actions that some of the compounds exhibit. The major agents exerting antiarrhythmic actions are verapamil, diltiazem, gallopamil, tiapamil, and bepridil; the dihydropyridines are devoid of significant electrophysiologic actions in vivo. Calcium antagonists prolong intranodal conduction time, lengthen the effective and functional refractory periods in the AV node, but exert little or no effect on atrial, ventricular, His-Purkinje, or bypass tract conduction or refractoriness (except in the case of bepridil, which has additional electrophysiologic properties). These effects form the basis of the clinical antiarrhythmic effects of this class of agents. The most striking action is the predictable and prompt termination of reentrant supraventricular tachycardia by intravenous verapamil and diltiazem and the slowing of the ventricular response in atrial flutter and fibrillation. These agents may also be of value in the chronic control of ventricular response in atrial flutter and fibrillation; their role in multifocal atrial tachycardia and other ectopic tachycardias is less well defined. Calcium antagonists reverse ischemic ventricular arrhythmias due to coronary artery spasm but exert little or no action in the usual forms of sustained ventricular tachyarrhythmias associated with severe structural heart disease. They are poor suppressants of premature ventricular contractions. Recent data have established their role in exercise-induced tachycardia occurring in the context of ischemic heart disease; they are also of value in ventricular tachycardia occurring in young subjects developing tachycardia with a right bundle branch block with left axis deviation morphology, an arrhythmia thought to be due to triggered automaticity. The role of calcium antagonists in reducing the incidence of sudden death in the survivors of acute myocardial infarction remains uncertain.
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PMID:Control of cardiac arrhythmias by calcium antagonism. 328 60

Real-time directed M-mode echocardiography permits analysis of atrial and ventricular mechanical systole and allows inference of the type of arrhythmia present. Accurate diagnosis in cases of fetal tachyarrhythmia is of vital importance when therapy is considered, and in planning further management and delivery of an affected infant. Fetal tachyarrhythmia may be life-threatening especially when fetal hydrops is present and aggressive therapy is mandatory in these cases with digoxin being the drug of choice. In our series the incidence (8.3%) of congenital heart disease was as expected, but the incidence (54%) of atrial flutter was surprisingly high. The prognosis was dependent on the presence or absence of fetal hydrops and was not influenced by the type of arrhythmia or gestational age.
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PMID:Cardiac tachyarrhythmia in the fetus: diagnosis, treatment and prognosis. 350 12

The frequency and severity of cardiac arrhythmias were studied in 70 patients with spontaneous subarachnoid hemorrhage investigated prospectively with 24-hour Holter monitoring. Patients were less than 70 years old and without clinical and/or ECG signs of previous heart disease; Holter monitoring was initiated within 48 hours of subarachnoid hemorrhage. Arrhythmias were detected in 64 of the 70 patients (91%). Twenty-nine of the 70 patients (41%) showed serious cardiac arrhythmias; malignant ventricular arrhythmias, i.e., torsade de pointe and ventricular flutter or fibrillation, occurred in 3 cases. Serious ventricular arrhythmias were associated with QTc prolongation and hypokalemia. No correlation was found between the frequency and severity of cardiac arrhythmias and the neurologic condition, the site and extent of intracranial blood on computed tomography scan, or the location of ruptured malformation. The extremely high incidence of cardiac arrhythmias, sometimes serious, in the acute period after subarachnoid hemorrhage and the absence of clinical and radiologic predictors make systematic continuous ECG monitoring compulsory to improve the overall results of subarachnoid hemorrhage, irrespective of early or delayed surgical treatment.
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PMID:Subarachnoid hemorrhage: frequency and severity of cardiac arrhythmias. A survey of 70 cases studied in the acute phase. 359 Feb 46

Fifty-seven episodes of atrial flutter in 46 consecutive medically treated patients (aged 60 +/- 17 years) were treated by rapid atrial pacing. Thirty-three patients (72%) had structural heart disease. Most pacing trials were conducted in patients receiving digoxin (88%) and antiarrhythmic drugs (77%). In 51 of 57 trials (89%), patients were successfully converted to normal sinus rhythm. Multivariate analysis revealed that patients who had congestive heart failure and who were older were more likely to be refractory to pacing. Left atrial size did not influence outcome. Confirmation of local atrial capture with a bipolar atrial electrogram and use of multiple atrial pacing sites enhanced the success rate. Eight patients (17%) demonstrated sinus node suppression after atrial pacing; sinus node disease was previously unsuspected in 4 of these patients. These bradyarrhythmias were easily managed because a pacing catheter was already in place. The only significant complication was femoral vein thrombosis in 1 patient. It is concluded that atrial pacing is an effective, safe and convenient method for the elective conversion of atrial flutter in the general population of medically treated patients. This technique is an attractive alternative to transthoracic cardioversion, and may be preferable in many patients.
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PMID:Atrial pacing for conversion of atrial flutter. 372 39

The most suitable approach to the athletes with WPW is controversial. Therefore 66 symptom-free athletes with WPW and without heart disease (53 M, 13 F, mean age 21.98 yrs, min 12--max 44) underwent a study protocol whose end-point was the induction of supraventricular tachyarrhythmia, i.e. atrial fibrillation or, if not possible, atrial flutter or atrial tachycardia at rest and during ergometric stress test. The athletes with shortest R-R interval between preexcited beats less than or equal to 240 ms at rest and/or less than or equal to 210 ms during exercise were judged as being at risk i.e. no fit for sport activity. The end-point was reached in 64/66 athletes (in 62 atrial fibrillation). In 4 athletes with life threatening arrhythmia induced at rest the evaluation during exercise was not performed. According to the evaluation at rest we were able to identify only 18 athletes (28.1%) as being at risk, while according to the complete study protocol 26 athletes (40.6%) were judged as such. In 23/64 athletes (36%) this judgement was discordant with the usual non invasive evaluation (i.e. Holter monitoring, ergometric stress test, ajmaline test). During induced atrial fibrillation no significant difference, was found between the percentage of preexcited beats at rest and during exercise. On the average, 40 min. are required for performance of this study protocol (if the induced arrhythmia lasts less than 5 min.). According to our results we conclude: a) the non invasive assessment of the WPW athletes is unsatisfactory; b) the induction of atrial fibrillation during exercise gives a remarkable increase of the diagnostic power with respect to the assessment only at rest; c) since it is simple to perform and not expensive (in time, staff and cost) and because of its high diagnostic yield, we regard this protocol as fundamental for the electrophysiological evaluation of WPW athletes and also suitable for systematic study of WPW patients.
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PMID:[Electrophysiologic evaluation of athletes with Wolff-Parkinson-White syndrome: induction of supraventricular arrhythmia at rest and under exertion with transesophageal atrial electrostimulation]. 379 28

Clinical and instrumental (ECG, PCG, ultrasonic cardiography and polycardiography) examination of cardiac activity in 98 breast cancer patients treated at the Center after Cooper established the cardiotoxic effect of 5-fluorouracil, vincristine, methotrexate, cyclophosphamide and corticosteroids. 46% of them suffered pain in the region of the heart, tachycardia, extrasystole, atrial flutter and deranged conduction function. Congestive heart failure was observed in 7% only. In 24%, myocardial lesions could be detected by instrumental means only. They were identified on the basis of an increase in terminal diastole and systole volume and mass of the myocardium matched by a decrease in stroke volume, PCG amplitude, % delta S and VCF. Cardiac disorders did not persist and were hardly detectable during medication course intervals or one-two months after treatment.
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PMID:[Cardiotoxic effect of cytostatics in patients with breast cancer]. 384 Mar

Twenty-four-hour electrocardiograms were recorded in 50 subjects (44 women, 6 men) older than 80 years without cardiovascular disease and with normal standard electrocardiographic responses. During waking and sleeping periods, the mean sinus rates were, respectively, 78 +/- 3 and 64 +/- 1 beats/min; heart rate ranged from 43 to 180 beats/min over 24 hours. Supraventricular tachycardia (SVT) was present in 28% of the subjects. Nocturnal sinus arrhythmia was only noted in 12% of the patients; it was accompanied by sinus pauses of 1.8 to 2 seconds, and 1 woman had a transient pattern compatible with atrioventricular dissociation. Supraventricular ectopic contractions (SVECs) were present in all cases. The frequency was less than 1 per hour in 25% and more than 20 per hour in 65%. Serious supraventricular tachyarrhythmias included an episode of ectopic atrial tachycardia (1 subject), a short run of atrial fibrillation (1 subject) and of flutter (1 subject), and several episodes of supraventricular tachycardia (2 subjects), all accompanied by more than 50 SVECs per hour. The number of ventricular premature contractions (VPCs) exceeded 10 per hour in 32% and were multifocal in 18%. There were couplets in 8% and a run of 6 VPCs in 1 subject (2%). In conclusion, sinus pause and atrioventricular block are unusual in people older than 80 years without apparent heart disease. In contrast, frequent SVECs and VPCs are more common. This study stresses the difficulty of evaluating the normality of the electrocardiogram with portable monitoring in the older population.
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PMID:Findings on ambulatory electrocardiographic monitoring in subjects older than 80 years. 394 53

The records of 90 patients with Wolff-Parkinson-White syndrome who presented with supraventricular tachycardia in the first 4 months of life were reviewed. Among these, 63% were male. Structural heart disease was present in 20%, most commonly Ebstein's anomaly. All patients presented with a regular narrow QRS tachycardia, and pre-excitation became evident only when normal sinus rhythm was established. Only one infant had atrial flutter and none had atrial fibrillation. Type A Wolff-Parkinson-White syndrome was most common (49%), with heart disease occurring in only 5% of these patients. In contrast, heart disease was identified in 45% of those with type B syndrome. Initially, normal sinus rhythm was achieved in 88% of the 66 infants treated with digoxin with no deaths. Normal sinus rhythm resumed after electrical countershock in 87% of the 15 infants so treated. Maintenance digoxin therapy was used in 85 patients. The Wolff-Parkinson-White pattern disappeared in 36% of the patients. Four infants died of cardiac causes during the mean follow-up period of 6.5 years. Two of these four infants had congenital heart disease; the third, with a normal heart initially, developed ventricular fibrillation and died from a cardiomyopathy considered related to resuscitation. The remaining infant, with a normal heart, died suddenly at 1 month of age. All were receiving digoxin. A wide QRS tachycardia later appeared in three patients, all with heart disease, one of whom died.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Wolff-Parkinson-White syndrome and supraventricular tachycardia during infancy: management and follow-up. 396

One hundred nineteen patients with unexplained syncope (82%) or presyncope (18%) underwent complete electrophysiologic study (EPS). Symptoms were recurrent in 72% of the patients. Fifty-two percent of the patients had structural heart disease. Forty-one patients had normal EPS results and 78 had electrophysiologic abnormalities (ventricular tachycardia in 31, induced atrial flutter/fibrillation in 17, vasovagal syncope in 8, hypersensitive carotid sinus syndrome in 7, supraventricular tachycardia in 6, heart block in 5 and sick sinus syndrome in 4). The presence of structural heart disease (p = 0.0033) and previous myocardial infarction (p = 0.05) were the only clinical or electrocardiographic predictors of a positive EPS response. Therapy was guided by EPS and patients were followed for 27 +/- 20 months (mean +/- standard deviation). In the patients with negative EPS results, 76 +/- 11% (mean +/- standard error) were symptom-free at follow-up, compared to 68 +/- 10% in the group with positive EPS responses. No clinical variables helped to predict remission in the absence of therapy. One patient in the negative EPS response group and 2 patients in the EPS positive group died suddenly (cumulative survival 94 +/- 4%). Total cardiovascular mortality was 13% in the positive EPS response group, and 4% in the negative EPS response group. Thus, certain clinical characteristics are helpful in selecting patients for study. Electrophysiologically guided therapy is associated with a recurrence and sudden death rate similar to an untreated control group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Electrophysiologic evaluation and follow-up characteristics of patients with recurrent unexplained syncope and presyncope. 397 12

Two hundred twenty-four patients underwent ventricular programmed stimulation (VPS) without prior documentation of the clinical occurrence of sustained ventricular tachycardia (VT) or ventricular fibrillation-flutter (VF). Indications for VPS were: palpitations or nonsustained VT during ambulatory monitoring (85 patients), syncope or presyncope (137 patients), and a family history of sudden death (two patients). Sustained VF requiring transthoracic defibrillation was initiated by VPS in 18 patients (8.0%). Four patients were treated for inducible VF with antiarrhythmic agents directed by electropharmacologic testing; five patients were treated empirically; nine patients received no therapy. No patient has had a cardiac arrest or sudden death during a follow-up period 25.2 +/- 13.8 months (mean +/- standard deviation). VF was initiated by two ventricular extrastimuli in three patients and by three extrastimuli in 15 patients. The incidence of VF was similar in patients with and without previous symptoms (8.8% vs 6.9%) or heart disease (7.1% vs 9.6%). It was significantly higher when VPS at three ventricular sites with a current of 5 mA (pulse width 2 msec) was compared to programmed stimulation at two ventricular sites with a current twice diastolic threshold (pulse width 2 msec) (15.2% vs 3.0%, p less than 0.05). VF initiated by VPS in patients without prior VT or VF appears to be a nonspecific finding. Antiarrhythmic therapy for VF may not be necessary in these patients.
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PMID:Clinical significance of ventricular fibrillation-flutter induced by ventricular programmed stimulation. 399 30


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