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Idiopathic long q-t syndrome: brief case report and discussion.

Idiopathic long q-t syndrome (LQTS) is an infrequently occurring familial disorder in which affected family members have an abnormally prolonged q-tc interval with syncope, ventricular arrythmias and sudden death. In this article, we present the case of a 54-year-old female admitted for syncope, who was on no medications except for insulin. Her electrocardiogram on admission had prolonged q-tc interval (0.50 ms.). She had repeated episodes of torsades de pointes during her hospitalization, which were later controlled by beta-blockers. Electrocardiograms of her mother and daughter showed asymptomatic prolonged q-tc interval. This syndrome has an autosomal dominant pattern of transmission and it was first described by Romano and Ward in a patient with normal hearing. Our case is unusual because this condition presented so late in life.

Algorithms↗

[Ventricular tachycardia due to premature supra-ventricular beats with a normal QRS complex. Analysis of a case].

Report of attacks of ventricular tachycardia in a 39 year-old man, free from heart disease. Cardiac pacing showed that the tachycardia could be induced by premature supraventricular beats normally propagated to the ventricles, and by atrial acceleration. The same part played by the cardiac rate on triggering of attacks was demonstrated during ventricular pacing. Besides, the possibility to interrupt the tachycardia by one electrically induced ventricular beat, supports the hypothesis of a re-entry machanism. The QRS configuration during the arrythmia suggested a propagation of excitation starting from the posterior-inferior area of the left ventricle. However, the absence of anomalies of the supraventricular beats initiating the tachycardia excluded a circus movement resulting from a unidirectional block on the left anterior hemibranch. More probably there existed an area of micro-reentry, stimulating the left ventricle from the posterior branches of the His-Purkinje system.

Adult↗

Ventricular aneurysmectomy: indications, operative findings and outcome at a single centre.

We assessed all patients (n = 120) who underwent left ventricular aneurysmectomy as part of a cardiac surgical procedure at the Groby Road Hospital subregional cardiothoracic centre (1980-1990). Of these, 71% had had only one prior myocardial infarction and 84% had symptoms generally associated with aneurysms (congestive cardiac failure, ventricular arrythmias or systemic embolism). The indication for surgery was a combination of angina and aneurysm-related symptoms in 43%, one or more aneurysm-related symptoms in 35%, and angina alone in 22%. The majority of patients (57%) underwent aneurysmectomy and coronary artery bypass grafting, although 35% underwent aneurysmectomy alone. Most (61%) aneurysms were > 6 cm in size, and 75% were located at the apex of the left ventricle. Forty per cent had a mural thrombus, and there was no relationship between prior warfarin use and occurrence of mural thrombus. Overall perioperative mortality was 17% (20 patients), although mortality halved between the first and second halves of the study period. The main reason for perioperative was pump failure. Seventeen patients died late during follow-up (mean 52.5 months), the main cause being further myocardial infarction. Nevertheless, 65% were still alive at 5 years, and 81% and 66% of survivors were still better than pre-operatively at 5 and 8 years, respectively. Post-operative improvement was equally as good in patients who underwent aneurysmectomy alone, or those operated on for aneurysm-related symptoms, as in the whole group. In logistic regression analysis, the only predictor of adverse long-term outcome was the number of previous myocardial infarctions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Influence of pretreatment with phenytoin, lidocaine and quinidine on the cardiodynamic and electrophysiological effects of ouabain in the cat heart-lung preparation.

The effect of pretreatment with phenytoin (diphenylhydantoin), lidocaine, and, for comparison, quinidine, on the doses of ouabain which produce a maximal inotropic effect, onset of arrhythmias and cardiac arrest, was explored in the cat heart-lung preparation. Ouabain was administered as an infusion (0.5 micrograms/min) either alone or after treatment with phenytoin (0.095 +/- 0.012 mM), lidocaine (0.090 +/- 0.004 mM) or quinidine (0.028 +/- 0.006 mM) and the cardiodynamic and electrophysiological changes monitored. Phenytoin, lidocaine and quinidine were administered in doses which were maximally tolerated by the preparations to ensure full effect, as evidenced by early cardiac depression. Ouabain alone produced a maximal increase in contractility prior to the development of arrhythmias at a blood concentration of 0.212 +/- 0.014 microM, onset of arrythmias at 0.227 +/- 0.015 microM, stable ventricular tachycardia at 0.269 +/- 0.010 microM and cardiac arrest at 0.342 +/- 0.014 microM. Pretreatment with phenytoin or lidocaine did neither modify these values nor change the pattern of the arrhythmias or the terminal cardiac event. Pretreatment with quinidine prevented the development of ventricular extrasystoles and aberrant ventricular conduction, which were the earliest arrhythmias in all other series. It also made the preparations develop stable ventricular tachycardia at an ouabain blood concentration of 0.246 +/- 0.007 microM, which was not significantly different from the concentration at which early arrhythmias were noted in the other series. In addition, quinidine decreased the dose of ouabain producing cardiac arrest by 13% but did not modify the terminal event. Pretreatment with phenytoin, lidocaine and quinidine did not affect the electrocardiographic pattern, but at the maximal increase in contractility with ouabain prior to the development of arrhythmias, the PR interval increased to comparable limits with ouabain alone and ouabain after quinidine and lidocaine. However, with ouabain after phenytoin, this increase was 61% less than that with ouabain alone and 31% less than that with ouabain after quinidine. Ouabain given alone or after phenytoin, lidocaine or quinidine produced comparable maximal effects on dp/dt, -dp/dt and left atrial pressure. It may be concluded that pretreatment with phenytoin and lidocaine does not modify the maximal inotropic dose of ouabain prior to the development of arrhythmias, the arrhythmogenic dose or the dose producing cardiac arrest, and that phenytoin partly counters the ouabain-induced depression of AV conduction. Quinidine has an additive effect on the ouabain-induced depression of AV conduction, prevents the ouabain-induced increase in idioventricular rhythm responsible for extrasystoles but not that responsible for ventricular tachycardia, and reduces the dose of ouabain producing cardiac arrest.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

Wolff-Parkinson-White syndrome type A obscured by left bundle branch block.

2 patients are presented whom the presence of left bundel branch block obscured the signs of the Wolff--Parkison--White syndrome expected with a bypass on the left side of the heart. While it was possible to infer the presence of both disorders from the surface ECGS, electrophysiological studies proved invaluable in defining the precise situation in both cases. When atypical electrocardiographic appearances are observed in the Wolff-Parkinson-White syndrome, careful investigation may reveal the cause to be bundle branch block on the same side of the hear as the anomalous pathway. In both patients there was in addition evidence of sinoatrial disease, which was associated with the occurrence of arrythmias, and this was also confirmed with intracardiac studies.

Adult↗

[Comparison of airway complications on tracheal extubation in deeply sevoflurane anesthetized versus awake children].

We investigated the incidence of respiratory complications and oxygen saturation level during emergence from sevoflurane anesthesia in children whose tracheas were extubated while they were anesthetized or after they became awake. Thirty children, aged 1-10 years, were studied. Anesthesia was induced with sevoflurane or thiopental and maintained with nitrous oxide, oxygen and sevoflurane. After nitrous oxide was discontinued at the end of surgery, the patients were randomly assigned to two groups: deeply anesthetized extubation group (anesthetized group) and awake extubation group (awake group). In anesthetized group, the patients were extubated while they were administered 1.5% or higher sevoflurane in 100% oxygen. In awake group, extubation was performed while the patients were awake. The incidence of respiratory complications such as apnea, laryngospasm, bronchospasm and arrythmias was not significantly different between the two groups. There was a significantly higher incidence of the airway obstruction but less incidence of cough and breath-holding in anesthetized group. Oxygen saturation level before and after tracheal extubation was not different between the two groups. In conclusion, with proper attention to airway obstruction, it may be possible to extubate while children are deeply anesthetized with sevoflurane.

Anesthesia, Inhalation↗

Ventricular tachycardias induced by intracoronary administration of endothelin-1 in dogs.

In 12 anesthetized, open-chest mongrel dogs, endothelin-1 (ET-1) was infused into the left anterior descending coronary artery through an indwelling catheter at a dose of 30 pmol.min-1 for 30 min (n = 8). In four dogs the ET-1 dose was increased to 60 pmol/min for 10 min. Programmed electrical stimulation was used for electrophysiologic studies. Coronary blood flow was reduced by 32% on average without any ischemic ECG signs. QT time (186 +/- 3 ms vs. 218 +/- 6, p < 0.05, and 225 +/- 9, p < 0.05, p < 0.05). Ventricular irritability increased in all cases; ventricular extrasystoles, and nonsustained and sustained tachycardias occurred and, in 11 cases, ventricular fibrillation terminated the experiments. In two dogs, early afterdepolarization was recorded. Therefore, ET-1 is capable of inducing fatal ventricular arrythmias at least partly independent of its vasoconstrictor effect. QT prolongation appears to have a pathophysiologic role in this arrythmogenic effect.

Action Potentials↗

Computer-assisted instruction of arrhythmia for MS-windows.

1. INTRODUCTION. Training in the diagnosis of arrhythmias is an important part of the curriculum for medical students, postgraduates, and paramedical staff. Although several CAI for arrhythmia have been developed [1-3], we could not get CAI software for arrhythmia for the MS-Windows environment. In this report, we present a newly-developed computer-assisted reference system for arrhythmia that functions in the Windows environment. 2. DESCRIPTION OF THE SYSTEM. The system consists of a program and two data files. An MS-Windows program (ECG9405.EXE, 180kB) was compiled using Borland's C++ v.3.1. A binary file (ECPAT.BAS 33kB) includes data of normal and abnormal wave segments of ECG: P wave, PQ interval segment, and QRs complex with/without T wave. A mother file (ECG9405.sys, 57kB) includes 85 data sets to generate ECG waveforms of arrhythmia. Each data set contains a sequence of wave form numbers, the text for questions and answers, and the commands strings. There are five major commands: 1) to create a new window as "wave window"; 2) to make electrocardiogram data; 3) to plot the data on the window; 4) to create a "dialog box" for questions and explanations; and 5) to check the answers. he program gets a data set from the data according to the user's choice. The program then interprets the data set and executes the commands. The wave segment data are plotted in a "wave window" at every 10 milliseconds; this is controlled by the MS-Windows' timer. The timer interval can be changed by selecting the speed button. The ECG waveforms are displayed on a window just like an ordinary ECG monitor with beat sound. Many windows can be created by the user and many ECG waves simultaneously plotted on CRT. 3. USAGE OF THE SYSTEM. The "main window" has a menu that has three items corresponding to the training course: BASIC, TRY, and TEST. Thirty-five types of arrythmias are listed in the "list box" of the windows in BASIC course e.g., sinus arrhythmia, atrial flutter, atrial premature contraction, ventricular extrasystole, ventricular flutter, etc. If the user selects one of them on the list by double clicking, some textual explanations of the wave are described in a dialog box. Ten multiple choice questions are displayed in the dialog box in course of learning TRY and TEST; the answers to these are requested. In the TEST course, the system offers random access to each arrhythmia. he user can send the pictorial ECG data in the window to other graphics programs through a clip board. 4. DISCUSSION. It was successfully used in a lecture of electrocardiogram for medical students. They seem to be interested in this system because of its simple usage and the dynamic drawing of ECG waves on CRT. Multiple computer-based medical resources can be run on MS-Windows. The system is able to run simultaneously with other programs, such as an electronic reference system [4]. The system may be obtained from the authors upon request.

Arrhythmias, Cardiac↗

[Heart and thyroid].

Thyroid hormones may exert cardiovascular actions by direct effects on the myocardium, by interacting with the sympathetic nervous system and through alterations of the peripheral circulation. Then, thyroid hormones increase myocardial contractility and relaxation, sensitise the myocardium to sympathetic nervous system and decrease arterial resistance. Hyperthyroidism results in an enhanced myocardial contractility, an increased cardiac output and a fall in systemic vascular resistance. Nevertheless "high output" cardiac decompensation may occur. Thyrotoxicosis may trigger arrythmia and disease seems to be associated with an increase in the frequency of mitral valve prolapse. Even in mild or subclinical hyperthyroidism complication may occur. Sympathetic blocking agents are the treatment of choice in addition to aetiologic treatment. Hypothyroidism is associated with bradycardia, a decreased cardiac output, increased vascular resistance and perhaps a decreased sensitivity of the sympathoadrenal system. An increase in cholesterolemia leads to an additional risk for the development of atherosclerosis. Main cardiovascular complications of hypothyroidism are angina pectoris, diastolic hypertension, atrio-ventricular blocks or pericarditis. Mild hypothyroidism might also be correlated with an increase in adverse effects.

Cardiovascular Diseases↗

[Radioelectrocardiographic record in workers employed in railroad repair shops].

Cardiac response to the physical effort due to occupational work was studied in 33 workers employed in a railway repair shop by means of radioelectrocardiography. The HR ranges, HR mean values and r-ecg changes in different professional groups are described. Attention was paid to the pronounced sinus arrythmia observed in subjects performing hard work. The quantitative and qualitative changes of the obtained results were described and the difficulties in the evaluation of r-e.c.g. records obtained during dynamic examination were emphasized.

Adult↗

[Anomalous origin of the left coronary artery from the pulmonary artery coronary revascularization under normothermic coronary perfusion in an infant].

A 5-months-old baby was hospitalized with congestive heart failure. Anomalous origin of the left coronary artery from the pulmonary artery was diagnosed on echo cardiography and coronary angiogram. Preoperative examination revealed severe left ventricular dysfunction (left ventricular end-diastolic pressure was 32 mmHg, left ventricular ejection fraction was 16%). Coronary revascularization was performed by anastomosis of the neo-left coronary artery to the aorta using an autologous pulmonary arterial roll under normothermic coronary perfusion. Although postoperative CPK-MB was within normal limits, the patient died on the 12th postoperative day due to ventricular arrythmia. Autopsy revealed severe endomyocardial fibroelastosis.

Cardiac Surgical Procedures↗

[Acute postoperative arterial ischemia (author's transl)].

The authors analyse 16 cases of acute ischemia observed over a period of one month after an operation of general surgery. The classical cardiac origin, e.g. infarct, arrythmia, was found in only three patients. The septic etiology was predominant, septic arterial emboli but not infective or acute thrombosis during septic or post-operative shock. The clinical aspect showed no special characteristics. Surgery remains the principal form of treatment. The results are good, except in acute arterial thrombosis justifying plastic surgery which may give better results than simple thrombectomy.

Adult↗

[Automatic implantable defibrillator and antiarrhythmic surgery in ischemic cardiopathies. Apropos of 53 cases].

The automatic implantable defibrillator (AID) and antiarrhythmic surgery are the two therapeutic options after failure of catheter ablation and/or antiarrhythmic therapy for sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) in patients with coronary artery disease. The authors undertook retrospective study of the characteristics of two groups of patients treated between November 31st 1987 et December 31st 1993 either by AID (28 men and 4 women with an average age of: 56.1 +/- 11.2 years) or by surgery (19 men and 2 women with an average age of: 60.6 +/- 6.8 years). The "surgical" patients differed from "defibrillator" patients in the fewer number of cardiac arrests, a higher proportion of sustained monomorphic VT, better tolerated sustained monomorphic VT (rarely syncopal), fewer early post-infarction arrythmias (< or = 8 weeks), more anterior wall infarction and a higher proportion of aneuvrysms. The perioperative mortality was 6.2% in the "defibrillator" group and nil in the "surgical" group (p = NS). At 2 years, the sudden death rate in the "defibrillator" and "surgical" groups was 7.5% and 0% respectively and total cardiac mortality was 17% and 20% respectively (p = NS). The authors conclude that perioperative mortality and the sudden death rate at 2 years are relatively low in the two groups. However, the total cardiac mortality remains high, largely related to perioperative death and secondary cardiac failure. Nevertheless, compared with defibrillator patients and with identical average ejection fractions, there was no extra mortality due to cardiac failure after antiarrhythmic surgery.

Aged↗

[Dysrhythmias documented by 48-hour electrocardiographic monitoring in children with mitral valve prolapse].

The association of dysrhythmias with mitral valve prolapse (MVP) in pediatric patients was examined by 48-hour ECG monitoring. Fifty unselected children with clinical diagnosis of MVP confirmed by echocardiography were studied. Eight (16%) patients manifested atrial dysrhythmias. Long runs of junctional rhythm with activity were recorded in one patient. Episodes of supraventricular tachycardia were recorded in 4 (8%) children. Seventeen (34%) patients had ventricular dysrhythmias. In 10 (20%) children, ventricular premature complexes (VPCs) were recorded. Four (8%) patients had frequent multifocal VPCs. Ventricular couplets were recorded several times in one patient (2%) and nonsustained ventricular tachycardia was recorded in two (4%) children. Clinical symptoms did not correlate with documented arrythmias. Although the prognostic implications of these findings are uncertain, this study demonstrated that potentially serious dysrhythmias are common in pediatric patients with MVP. It would appear that ambulatory ECG monitoring should be part of the complete evaluation of children with MVP.

Adolescent↗

Aminophylline and isoproterenol in the treatment of cerebral vasopasm.

Eighteen patients with cerebral vasospasm following subarachnoid hemorrhage were treated with 21 trials of intravenous aminophylline and isoproterenol. After angiographic demonstration of spasm, all patients were started on a continuous intravenous infusion of aminophylline 125 mg/hr and isoproterenol 125 micrograms/hr, preferably for a period of at least five days before the medications were tapered. Of the 21 treatment trials, there were 11 definite beneficial responses and ten failures. This study emphasizes the importance of instituting this therapy as rapidly as possible following the confirmation of symptomatic cerebral vasospasm. In addition, if a response occurs it will be noted within 24 hours of institution of the medications. If no response is noted following this time period, the medications should be discontinued. The major complications of this therapy include hypotension, tachycardia and arrythmias. These complications may necessitate diminishing the dosage of the medications. However, if a response has been obtained, every effort should be made to avoid discontinuing therapy prematurely since cerebral vasospasm may recur. The use of isoproterenol and aminophylline is based on their demonstrated ability to increase cyclic adenosine monophosphate (cyclic AMP) levels in vascular smooth muscle, thus producing relaxation of vasospasm.

Adolescent↗

Etilefrine in the prevention of prolonged erection after diagnostic pharmacological stimulation.

The aim of this study was to verify the efficacy and safety of intracavernous injection of etilefrine hydrochloride in the prevention of pharmacologically induced prolonged erection. Two hundred rigid erections due to diagnostic pharmacological stimulation were treated with immediate intracavernous injection of 5 to 10 mg etilefrine hydrochloride. Penile response and general side effects after the injection were recorded. Patients were interviewed after 1-2 weeks about possible side effects. Detumescence occurred within 10 minutes in 194 (97%) cases. In the remaining six (3%), detumescence occurred after cavernous aspiration and additional injection of 5 mg etilefrine. Thirteen patients (6.5%) had transitory palpitations. None of the patients had hypertensive crisis, cardiac arrythmia or ischaemic events. Intracavernous injection of etilefrine is effective and safe in preventing prolonged erection after diagnostic pharmacological stimulation.

Adult↗

[Carbon monoxide poisoning: current aspects].

Carbon monoxide (CO) poisoning still represents a frequent and severe casualty in France. Aside the well-known effect of CO on hemoglobin, the role of CO binding to other hemoproteins like myoglobin and cytochrome a3 have been more recently recognized. Moreover, in addition to these hypoxic injuries, the reoxygenation phase may itself induce toxic effects by a mechanism close to the ischemia-reperfusion phenomenon. Clinical manifestations include neurologic disturbances, cardiac arrythmia, respiratory and circulatory failures which usually disappear with removal from toxic atmosphere and administration of oxygen. However, long term neurologic manifestations may occur and lead to important functional impairment and disability. Hyperbaric oxygen in actually the treatment of choice to avoid the occurrence of delayed sequelae. HBO is advocated in every patient who remains comatose on hospital admission, who had lost consciousness during toxic exposure or with persisting neurologic abnormalities. CO poisoned pregnant women should also undergo HBO. Well designed prevention programs are urgently needed in our country to decrease the incidence and the consequences of CO poisoning.

Carbon Monoxide Poisoning↗

Effect of almokalant a specific inhibitor of IKr on myocardial ischaemia-reperfusion induced arrhythmias in rabbits.

The antiarrhythmic effect of almokalant, a new type III antiarrhythmic agent, was examined by occluding and releasing the left circumflex coronary artery for 10 min, respectively, in openchest, pentobarbital-anaesthetized albino rabbits. Almokalant pretreatment increased the number of animals developing no arrythmias (5/9 vs. 1/12 in controls), and decreased the incidence of ventricular fibrillation (1/9 vs. 9/12) during reperfusion. According to our results almokalant can protect the heart against arrhythmias induced by ischaemia and reperfusion.

Animals↗