Showing papers on "Sinus tachycardia published in 1985"

The heart and tuberous sclerosis. An echocardiographic and electrocardiographic study.

Abstract: Cross sectional echocardiography, 12 lead electrocardiography, and 24 hour ambulatory electrocardiography were performed in eleven patients with tuberous sclerosis. Echocardiography showed single or multiple intramyocardial masses, most commonly in the ventricular septum, suggestive of rhabdomyomata in seven of the eleven cases. One patient with a normal echocardiogram showed ventricular pre-excitation on electrocardiography, with tachycardias of 180 beats per minute on ambulatory monitoring. Sinus bradycardia, sinus tachycardia, and supraventricular tachycardia were also seen, but their importance is uncertain. Echocardiography and electrocardiography should be routinely performed in the assessment of patients with tuberous sclerosis and ambulatory electrocardiography should be considered in those with seizures that respond poorly to anticonvulsants.

Frequency-dependent effects of amitriptyline on ventricular conduction and cardiac rhythm in dogs.

Abstract: Although overdoses of tricyclic antidepressant are known to produce both sinus tachycardia and ventricular tachyarrhythmias in man, these have been assumed to occur by independent mechanisms. This study was designed to evaluate the relationship of ventricular activation frequency to the cardiotoxic effects of amitriptyline. When amitriptyline was infused into dogs with formalin-induced atrioventricular (AV) block to evaluate a broad range of pacing frequencies, the drug produced dose-related QRS prolongation that was markedly frequency dependent. Similar frequency-dependent depression of the maximum rate of depolarization (Vmax) was noted for canine Purkinje fibers superfused with amitriptyline in vitro. The time constant of recovery from amitriptyline-induced block was dose independent and averaged 228 msec in vivo and 216 msec in vitro. When amitriptyline was infused into dogs with intact AV conduction, sinus tachycardia occurred within 15 min, followed by progressive QRS prolongation and ventricular tachyarrhythmias after an average 29 min. Slowing of sinus rate by vagal stimulation (seven dogs) or intravenous metoprolol (five dogs) reproducibly reversed the QRS prolongation and ventricular tachyarrhythmias caused by amitriptyline. These studies show that amitriptyline produces frequency-related depression of ventricular conduction in vivo, with a time dependence similar to effects on the maximum rate of depolarization in vitro. Interventions that slow heart rate reverse the adverse effects of amitriptyline on ventricular conduction and cardiac rhythm.

Physiologic Changes in Normal Pregnancy

Abstract: The state of pregnancy induces a multitude of anatomic, physiologic, biochemical, and psychological changes. It is imperative that the physician caring for pregnant patients be familiar with those normal changes lest they be interpreted as abnormal. Sinus tachycardia, systolic heart murmurs, cardiac enlargement, and dependent edema, which are common changes in pregnancy, can easily be interpreted as signs of heart disease. Thyroid enlargement, sinus tachycardia, and the finding of high protein-bound iodine can lead to the diagnosis of hyperthyroidism if one is not aware that those changes represent normal changes of pregnancy.

Effects of atenolol on exercise capacity in patients with mitral stenosis with sinus rhythm.

Abstract: Exercise capacity is frequently impaired in patients with mitral stenosis (MS) and sinus rhythm (SR). The resulting increased heart rate, which shortens the diastolic filling period, and the increased cardiac output lead to further elevations of left atrial pressure and subsequent pulmonary congestion. The effect of the β-receptor blocking agent atenolol, 100 mg/day, was assessed in 13 patients with MS and SR. Exercise performance was assessed using a modified multistage Bruce protocol after 2 weeks of placebo and after 2 weeks therapy with atenolol in a single-blind, crossover, placebo-controlled, randomized study. Atenolol resulted in significant decreases in mean heart rates at rest and during exercise (p = 0.0015) and a significant increase in total exercise time (p = 0.0015). Maximal exercise capacity was also significantly improved (p = 0.0015). All patients were both objectively and subjectively improved by atenolol. Thus, β-blockade with atenolol improves exercise capacity in patients with MS and SR and may be of benefit to most such patients. The improved effort tolerance is attributed to reduction of the exercise-associated sinus tachycardia by β-blockade, allowing a longer diastolic filling period and better left atrial decompression.

Absolute ethanol injection of the adrenal artery: hypertensive reaction.

Abstract: Transcatheter injection of 0.4 ml of absolute ethanol into the adrenal artery was performed in three Rhesus monkeys. The injection produced a mean increase of 60 mmHg in systolic blood pressure and 50 mmHg in diastolic blood pressure within two minutes. Hypertension was accompanied by cardiac arrhythmias (two monkeys) and sinus tachycardia (one monkey). These changes were probably related to an acute catecholamine release. Embolization of the inferior phrenic artery with Gelfoam powder produced only a mild blood pressure elevation in three monkeys (6 mmHg systolic pressure and 10 mmHg diastolic pressure).

Sinus node responses to perfusion pressure changes, ischaemia and hypothermia in the isolated blood-perfused dog atrium

Abstract: Sinus node responses to perfusion pressure changes, ischaemia and hypothermia were evaluated in 22 isolated blood-perfused dog atria. Sinus cycle length (SCL) was measured and sinoatrial conduction time (SACT) was estimated using the premature atrial stimulation technique (PAS) and the constant atrial pacing method (CAP). There was a good correlation between the results obtained with both techniques (r=0.8297) but CAP had less depressing action on sinus node automaticity. Increasing the perfusion pressure from 100 to 200 mmHg did not influence estimated SACT nor SCL. However, a reduction in perfusion pressure (from 100 to 50 mmHg) markedly shortened SCL without significantly decreasing estimated SACT. Lowering temperature from 37 to 25°C caused a linear increase in estimated SACT and SCL. Occlusion of the sinus node artery induced a sinus tachycardia which was not blocked by sotalol. Estimated SACT was significantly shorter 1 min after occlusion and longer 3 min after occlusion; this increase was significantly inhibited by atropine infusion. Thus, the increase in estimated SACT seen after occlusion might be related to cholinergic activity. However, the sinus tachycardia following a decrease in perfusion pressure might be due to activation of the stretch-receptors while the one seen after reduction in blood flow and occlusion of the sinus node artery seems more likely to be a consequence of ischaemia.

Emergency thoracotomy in an urban community hospital: initial cardiac rhythm as a new predictor of survival.

Abstract: Several authors have reviewed their experience with emergency thoracotomy in the university hospital setting. However, physicians in urban community hospitals are treating increasing numbers of patients who require emergency thoracotomy. To compare such experiences, the charts of all patients who underwent emergency thoracotomy in an urban community hospital during the years 1981 and 1982 were reviewed. In addition, the presenting cardiac rhythm was evaluated as a potential new prognosticator for survival in these patients. Forty-seven thoracotomies were performed during the two-year period. Thirty-nine (83%) were for penetrating trauma, of which 31 (66%) were for gunshot wounds and eight (17%) were for stab wounds. Eight patients (17%) underwent thoracotomy for blunt trauma. Of the 13 patients (28%) who survived and were discharged from the hospital, eight (17% of the total) had no neuorological deficit. Twenty-five patients (53%) presented in sinus rhythm, 23 in sinus tachycardia, and two in normal sinus rhythm. All survivors beyond the operating room were in this group (P

Case 34-1985

Abstract: Presentation of Case A 32-year-old man was admitted to the hospital because of cardiomyopathy with ventricular ectopy. He was well until nine months earlier, when an upper respiratory tract infection developed. Two weeks later he collapsed suddenly and was taken to another hospital, where an electrocardiogram showed ventricular tachycardia at a rate of 240. The intravenous administration of lidocaine was unsuccessful, and an attempt at electric cardioversion was followed by ventricular fibrillation; bretylium was administered, and the rhythm reverted to sinus tachycardia at a rate of 120, with complete right-bundle-branch block. Digoxin, procainamide, quinidine, disopyramide, and mexiletine were administered in . . .

Computer simulation of dual chamber pacemaker algorithms using a realistic heart model.

Abstract: Single and dual chamber pacing algorithms have been incorporated into a realistic computer model of cardiac electrical activation. The model enables different pacemaker algorithms to be tested, it allows prediction of their behavior, and it produces a simulated ECG record for each case. The computer model has been used to test eight different modifications of a simple DDD mode to prevent or terminate pacemaker-mediated "endless loop" tachycardia: (1) constant prolongation of the atrial channel refractory period; (2) prolongation of the atrial refractory period after a ventricular premature beat (VPB); (3) atrial pacing synchronously with a VPB; (4) simple rate control; (5) rate control in which the VA counter is not reset; (6) no ventricular pacing after an atrial premature beat; (7) rate limitation of atrial sensing; and (8) a combination of DDD and high frequency atrial stimulation modes. These modifications were tested with VPBs, atrial premature beats, atrial stimulation without capture, and accelerating sinus tachycardia. Only the pacemaker designed not to pace the ventricles following an atrial premature beat behaves satisfactorily in all four circumstances. Further possibilities for the development and use of a pacemaker-oriented computer heart model are discussed.

Clinical evaluation of bisoprolol in the treatment of extrasystoles and sinus tachycardia: an interim report.

Abstract: The effectiveness and safety of bisoprolol, a newly developed beta-adrenergic blocking drug, in the treatment of arrhythmias were evaluated in 17 patients with premature ventricular contraction (PVC), 8 with premature atrial contraction (PAC) and 7 with sinus tachycardia. More than 50% reduction of the PVC frequency was observed in 7 out of 16 patients. PVC was reduced in 2 out of 5 patients at a daily dose of 2.5 mg. The PAC frequency was decreased in 50% of the patients, and sinus tachycardia was improved in all 7 patients. Adverse reactions were observed in 8 of 32 patients. This preliminary study suggests that the antiarrhythmic effects of bisoprolol could be assessed starting at a daily dose of 2.5 mg to determine its optimal effective dose in Japanese patients.

[Damage to the heart from tumor irradiation in the thorax--an echocardiographic study]

Abstract: The authors give a review of 74 patients with radiation-induced heart disease which could be easily detected by echocardiography. In almost all of the patients a pericardial effusion (P.E.), with relative sinus tachycardia was found 3 to 4 weeks after onset of radiation and this was transient in some cases. This phenomenon was interpreted as an early radiation-induced reaction of the heart. 6 to 12 months after radiation, late damage of the heart occurred depending on field and total radiation dose. This manifested as massive P.E. with changes in ECG. Later there was damage to the myocardium caused by coronary sclerosis. The tendency to constrictive pericarditis was manifested not earlier than 3 years or later after radiation. The authors advise follow up of the irradiated patients case by case, checked by echocardiography, especially those who received more than 5000 rad to the heart area and therefore have high risk of late heart damage.

Left anterior hemiblock, complete right bundle branch block and sinus tachycardia in maprotiline poisoning.

Abstract: Maprotiline is a tetracyclic drug with effects similar to those of tricyclic antidepressants It has been suggested that tetracyclic antidepressants have fewer cardiovascular side-effects We describe a case with serious alteration of intraventricular conduction after maprotiline overdosage

Ventricular tachycardia in myocardial infarction: relation to heart rate and premature ventricular contractions.

Abstract: Analysis of monitored electrocardiograms, recorded in 77 patients during the first 48 hours following the onset of myocardial infarction, revealed 492 episodes of ventricular tachycardia with rates of 90-220 min-1. Characteristics of the ventricular tachycardia episodes were correlated with heart rate and with the rate and complexity of ventricular arrhythmias in the 10-min period preceding ventricular tachycardia. Ventricular tachycardia with rates of 140-180 min-1 and with a QS configuration was the most frequent event. The first ectopic complex of VT was R-on-T in only 17.2%. Sinus tachycardia was associated with significantly fewer episodes of VT with rates of 110-140 min-1 than when the sinus rate was normal. However episodes of ventricular tachycardia with rates of 181 to 220 beats min-1 were more frequent during sinus tachycardia. Analysis of the frequency of premature ventricular contractions in the 10-min period immediately preceding ventricular tachycardia revealed no premature ventricular contractions in 24.4% of cases. Multiple premature ventricular contractions with a frequency of greater than or equal to 5 min-1 were observed in 8.4% of cases, multifocal in 30.3%, couplets in 24% and early PVCs in 12.2%. In the minute before ventricular tachycardia, only 40.2% of cases displayed premature ventricular contractions. In that minute, complex premature ventricular contractions were distributed as follows: multifocal in 10%, couplets in 8.7% and early PVCs in 2.6% of cases. Out of the total of 492 runs of ventricular tachycardia, 5 cases (1%) resulted in ventricular fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Initial experience with physiological pacing.

Abstract: Fifty patients, aged 23 to 88 years, with permanent rate-responsive dual chamber pacemakers were studied prospectively for 14.1 ± 11.4 (S.D.) months after implantation to assess the benefits and complications associated with this technique. In 12 patients the device replaced a ventricular demand pacemaker. Minor complications associated with implantation occurred in one case. Atrial leads required repositioning because of increase in threshold and/or problems of sensing in five cases and ventricular leads in five. There were two patients with symptomatic pacemaker-related arrhythmias necessitating reprogramming; one patient with pacemaker-mediated tachycardia and one with pacemaker autoinhibition. Seven patients have died; one suddenly and possibly related to a pacemaker-triggered arrhythmia. Of 43 living patients, five are now programmed to the ventricular demand mode; two with atrial fibrillation, one with failed atrial lead repositioning, one with persistent sinus tachycardia, and one because of angina pectoris. Thirty-six of the 43 living patients are asymptomatic and a further six are symptomatically improved. All 12 patients changed from ventricular demand pacing have less symptoms. Rate-responsive dual chamber pacing is safe and appears to improve symptoms in most cases. Complications are infrequent and usually easily overcome. This mode of pacing should be considered in all patients with normal sinoatrial function in whom a permanent pacemaker is indicated.

The First Hour of Acute Myocardial Infarction Observed During Mobile Intensive Care

Abstract: Between September 1970 and February 1973, we studied 294 patients with acute myocardial infarction (MI) who were seen and managed within 1 h of the onset of symptoms. The 294 patients were alive when first seen or were successfully resuscitated. In 111 (38%) of the 294 patients the interval between the onset of symptoms and initial observation was not greater than 30 min.

[Pathogenesis of tachycardia in hyperthyroidism. Value of Holter monitoring and the use of a beta-blocker].

Abstract: The mechanisms of tachycardia in hyperthyroidism were investigated by means of Holter recordings of heart rate in 45 patients, 33 of whom had sinus rhythm and were left untreated. In the remaining 12 patients, recordings were taken after 3 days of treatment with either propranolol (120 mg/day; 6 patients) or pindolol (15 mg/day; 6 patients). Propranolol is a beta-blocker devoid of intrinsic sympathetic activity whereas pindolol possesses such activity. Changes in heart rate under the influence of each of these drugs were compared with those observed in 96 controls similarly treated. The difference in baseline heart rare between day and night was significantly higher (p less than 0.01) in patients with hyperthyroidism (17 +/- 1 QRS/min) than in controls (13 +/- 1 QRS/min). Day and night heart rates were increased by pindolol, the increase in night heart rate being significantly greater (p less than 0.05) in patients with hyperthyroidism (23.4 +/- 4.9%) than in controls (11.6 +/- 2.6%). These results suggest that sinus tachycardia in hyperthyroidism is related to an increase in the number of myocardial beta-adrenoceptors. They also indicate that thyrotoxicosis should not be treated with beta-blockers possessing intrinsic sympathetic activity.

[Fetal arrhythmias. Differential diagnosis, clinical significance and prognosis].

Abstract: Between June 1979 and June 1984 the authors observed 40 fetal arrhythmias in 11,122 births (0.36%). Initially there were problems of differential diagnosis with cardiotokography and fetal abdominal ECGs. However, these problems were surmounted with real-time sonography, supplemented with split-image echocardiography (M-mode technique) with video recording. In three-quarters of the cases supraventricular and ventricular extrasystoles were found. These forms of arrhythmias were clinically harmless. Follow-up examinations of the children confirmed the favorable long-term prognosis. One-quarter of the arrhythmias were high-risk cases. Supraventricular tachycardias, total AV block, sinus tachycardia and bradycardia, and congenital atrial fibrillation were found. There were five cardiac abnormalities in this group. Heart failure occurred in six fetuses and neonates. Four of ten infants died. Three infants remained in pediatric cardiologic care. In the light of the authors' experience, it is still too early to invest great hope in intrauterine treatment of the fetus. Intrauterine diagnosis at the earliest possible time and intensive cardiologic care, starting immediately after birth, can improve the prognosis in cases with high-risk arrhythmias.

Manufacture and clinical application of XZY-1 model computer assisted ECG automatic diagnosis system.

Abstract: The manufacture and clinical application of XZY-1 model computer assisted ECG automatic diagnosis system and its hardware and software frames are described briefly in this paper. The results of 234 ECGs analysed by this system were as follows: (1) For the analysis of normal ECGs, the sensitivity, specificity and accuracy of this system were all over 95%. (2) For ventricular hypertrophy, bundle branch block and myocardial infarction, the sensitivity, specificity and accuracy were all over go%. (3) For the diagnosis of sinus arrhythmia, sinus bradycardia, sinus tachycardia, low voltage and clockwise and counterclockwise rotation, the sensitivity was over 80 %, while the specificity and accuracy were over 90 %.

Detection and Discrimination of Supraventricular Tachycardia from Sinus Tachycardia of Overlapping Cycle Lengths

Abstract: For more than 15 years, pulse generators (PG) have been implanted for the control of tachyarrhythmias Patient-activated systems have not achieved wide acceptance due mainly to the need for direct patient participation Automatic antitachycardia PGs have been limited by lack of flexibility of programmable parameters and the inability to discriminate pace-terminable (PT) tachycardias from sinus tachycardia and other non-PT rhythms

Tachycardia Recognition by Implantable Devices

Abstract: Early tachycardia interruption pacemakers relied on the recognition of tachycardia by the patient and manual activation of the device. The first generation of automatic pacemakers utilized one or more specific heart rates to trigger the tachycardia conversion response. Such systems were vulnerable to activation by sinus tachycardia resulting from physical or emotional stress. In such situations the burst or competitive pacing which resulted was particularly likely to provoke unwanted and potentially dangerous arrhythmias. Second generation anti-tachycardia pacemakers utilize other criteria to distinguish pathological from physiological tachycardia. Amongst these additional criteria the rate of change of heart rate has been most widely applied. This has reduced the likelihood of false diagnosis of pathological tachycardia but there are still many situations in which the implanted device may be activated inappropriately. The most common setting for mistaken diagnosis is immediately following a pacemaker intervention when pathological tachycardia may be “reconfirmed”when only a post tachycardia fast sinus rate is present. Of the many tachycardia recognition criteria which have been proposed cardiac activation sequence, for example AV interval during tachycardia, is the most promising technique for the accurate diagnosis of specific pathological tachycardias.