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First-degree atrioventricular block in a young duodenal ulcer patient treated with a standard oral dose of ranitidine.

A 20-year-old male patient on oral treatment with ranitidine 300 mg/day in a single bedtime dose was admitted to hospital for a brief episode of syncope which had occurred 20 min earlier. All clinical, laboratory and instrumental examinations yielded negative findings, except for electrocardiographic evidence of first-degree atrioventricular block. Administration of atropine produced transient disappearance of the block, which disappeared altogether after discontinuing ranitidine treatment. Two separate rechallenges with ranitidine each produced recurrence of (asymptomatic) first-degree atrioventricular block at electrocardiographic examination, but oral treatment with cimetidine (400-800 mg/day) and famotidine (40-80 mg/day) induced no electrocardiographic abnormalities. The hypothesis that this patient may be abnormally susceptible to the cholinergic or cholinergic-like effect of ranitidine, a side effect unrelated to the drug's primary H2-blocking action, would appear to be consistent with evidence of an increased vagal tone of the atrioventricular node as revealed by atrial pacing. However, the ability of ranitidine to release histamine in man and the potential dysrhythmia-inducing effect of histamine should also be taken into consideration.

Administration, Oral↗

[Hemodynamics in atrioventricular block in acute myocardial infarct and its changes under the influence of electric stimulation of the heart].

Hemodynamics was studied in the initial condition and against the background of electric stimulation of the heart in 18 patients with acute myocardial infarction complicated by complete atrioventricular block. It is shown that block promotes the development of circulatory insufficiency in patients with myocardial infarction. The marked character of hemodynamic disorders and the changes induced in it by electric stimulation are determined in many respects by the functional condition of the left ventricle. In most patients with acute myocardial infarction complicated by complete atrioventricular block, with the exception of those with a clinical picture of cardiogenic shock, the main values of hemodynamics demonstrated against the background of electric stimulation hardly differ from the corresponding values in patients with myocardial infarction and no disturbances of atrioventricular conduction. During electric stimulation of the heart in the contingent of patients examined, the external work of the heart and the "tension/time" index considerably increase which suggests a marked increase in the myocardium requirements in oxygen. The probability of unbalanced increase in the requirements of the myocardium in oxygen against the background of electric stimulation dictates the necessity for raising its parameters to optimum levels.

Acute Disease↗

Electrophysiological and haemodynamic basis for application of new pacemaker technology in sick sinus syndrome and atrioventricular block.

A fundamental description of pacemaker systems which are commercially available or in clinical validation is given as a background for their application in a series of 62 consecutive patients presenting over a period of 1 year for permanent cardiac pacing. The patients (23 (37%) sick sinus syndrome, 38 (61%) atrioventricular block, and 1 ventricular tachycardia) were studied electrophysiologically and haemodynamically to allow the appropriate application of a pacemaker system. In sick sinus syndrome, 8 patients had permanent atrial pacing, 14 ventricular pacing, and 1 atrioventricular sequential pacing; in atrioventricular block, 8 patients had atrial synchronous ventricular inhibited pacing and the remaining 30 had ventricular pacing. A high incidence of atrial fibrillation, 9 patients, and abnormal sinus node function, 15 patients, precluded wider use of atrial synchrony. The results show benefit in acute haemodynamic studies of using systems including atrial sensing and/or pacing, and with greater availability of atrioventricular sequential and still more advanced pacemakers with dual sensing as well as dual pacing the majority of patients may be offered this benefit.

Aged↗

Is intrapartum temporary pacing required for women with complete atrioventricular block? An analysis of seven cases.

Women with complete atrioventricular heart block without a permanent pacemaker normally receive temporary pacing for labour and birth. Here, we report seven women who were managed without pacing. All women had a temporary pacing lead inserted prior to induction of labour, but none of the women required pacing during labour or birth. Our experience suggests that women with complete atrioventricular block and without permanent pacing do not routinely require temporary pacing for labour and birth.

Adult↗

[Predictive value of the ajmaline test for the diagnosis of distal paroxysmal atrioventricular block (author's transl)].

An ajmaline test was conducted in 120 patients with a history of disorders of consciousness : Adams-Stokes syndrome (n = 49), loss of consciousness (n = 42), or lipothymia (n = 29). Four types of response were observed after ajmaline : VH less than 80 ms (n = 63); VH between 80 and 100 ms (n = 19); VH greater than 100 ms (n = 17); distal block (n = 21). One hundred and fifteen of these patients were followed-up for from three to six years (mean 56 months). Pacemakers had been fitted in 46 of them. Atrioventricular block was eventually detected in 37 patients but was excluded in the other 78 cases, either because the syncope attacks did not recur or because another cause was demonstrated. The predictive value of the ajmaline test was confirmed by the subsequent course of the disorders. Based on only clinical findings, diagnosis was confirmed in 42 p. cent, excluded in 12 p. cent, and impossible to define in 46 p.cent of cases. After the ajmaline test, diagnosis was confirmed in 79 p.cent, excluded in 6 p.cent, and impossible to define in 15 p.cent. The risk of atrioventricular block can be evaluated as 1-6 p.cent when the increase in VH is less than 80 ms, 35.3 p.cent when the increase is between 80 and 100 ms, 62.5 p.cent when it is greater than 100 ms, and 100 p.cent when there is a distal block. The indications for fitting a pacemaker depend upon the results of this test. If contra-indications are respected (recent history of an infarct, cardiac failure, marked enlargement of the heart), complications are rare, being observed in less than 3 p.cent of cases.

Aged↗

Electrocardiographic characteristics of the escape rhythm in transient complete atrioventricular block induced by transcatheter electrical ablation of the atrioventricular junction.

The electrocardiographic characteristics of spontaneous escape rhythm during complete heart block induced by transcatheter ablation of the atrioventricular junction was prospectively studied in 21 patients by periodically interrupting temporary pacing. The data derived from 13 of these 21 patients, in whom conduction recurred after the procedure, were analyzed. An escape rhythm was present in 12 patients 8.2 +/- 5.8 minutes after shock delivery at a cycle length of 1985 +/- 974 ms. The escape QRS had a configuration of right bundle branch block with left axis deviation in 9 patients, of right bundle branch block with normal axis in 1, of left bundle branch block with left axis deviation in 1, and 2 distinct morphologies in the remaining patient. After resumption of conduction, the conducted complexes were identical to the escape complexes in six patients, different only in axis in four patients, and different in morphology in two patients. This suggests that in the majority of patients the escape rhythm seen during transient heart block, induced by transcatheter ablation of the atrioventricular junction, presents a right bundle branch morphology with or without a left axis deviation, and most likely originates from an area above, or close to, the site of the anatomical damage.

Adult↗

[Atrioventricular block in acute inferior myocardial infarction].

The underlying mechanism of atrioventricular block (AVB) in acute inferior myocardial infarction (AIMI) is not clearly understood. In 33 (27 males and 6 females) of 123 patients with AIMI, second and/or high degree AVB was observed. In 14 of the 33 patients (42%), AVB transiently appeared within 24 hours after the onset of AIMI. In 13 patients (39%) AVB appeared after 24 hours. In the remaining 6 patients (18%), AVB appeared within 24 hours and disappeared thereafter. Among these 3 groups, there were no significant differences in age, sex, serum enzymes, the appearance of high degree AVB, pump failure or Forrester's classification II, III and IV and the necessity of temporary pacing. One mg of atropine sulfate was administrated intravenously 35 times in 19 patients. When AVB improved or the ventricular rate increased more than 30%, the drug was regarded as effective. Atropine was more effective when administrated after 24 hours (11%, less than or equal to 24 hours vs 60%, greater than 24 hours, p less than 0.05), and in patients with a slight degree of AVB (28% in high degree vs 80% in second degree, p less than 0.05) and rapid ventricular rate during high degree AVB (0%, less than 40/min vs 45%, greater than or equal to 40/min, p less than 0.05). In the 6 patients not responding to atropine, 250 mg of aminophylline was given intravenously for 15 min. The effect was not seen in 4 patients, including 3 patients to whom it was administrated within 3 days after the onset of AIMI, and one patient to whom it was given on the 5th day. Aminophylline improved atrioventricular conduction on the 5th to 10th day after the onset of AIMI in 2 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗

[Total atrioventricular block as the primary clinical manifestation of undiagnosed aortic dissection].

We describe the case of a 54-year-old male who was examined due to light chest pain experienced the previous day. The man was admitted to the cardiology division for the presence of a complete atrioventricular block. On admission the echocardiogram showed a large aortic regurgitation not present two years earlier. Suspecting an aortic dissection we performed a transesophageal echocardiography and a contrast computerized tomography: the two examinations were negative. The next days the patient had two episodes of acute pulmonary edema so he was transferred to the regional reference hospital where an hemodynamic unit and cardiac surgery division were available. There, he repeated a transesophageal echocardiography which was negative. The man had aortic valve replacement without angiography for his very critical condition. The surgeon identified a small aortic dissection, just above the aortic valve plane, which was responsible for valve leaflets prolapse and aortic regurgitation; the hematoma deepened towards the interatrial septum and atrioventricular junction justifying the atrioventricular block. In conclusion, a small aortic dissection can offer an atypical picture, and in this condition even very valuable diagnostic techniques may fail the diagnosis.

Aortic Dissection↗

[A case of complete atrioventricular block after induction of general anesthesia].

A 75-year-old man with a past history of bilateral thalamic hemorrhage was scheduled for cholecystectomy and cholelithotomy under general anesthesia. Although the preoperative ECG showed a complete right bundle branch block, the echocardiogram revealed no abnormality. Anesthesia was induced with thiopental and vecuronium, and maintained with sevoflurane in oxygen. Soon after changing to the left decubitus position for the insertion of an epidural catheter, ECG showed complete atrioventricular block, which did not respond to atropine. Adrenalin was transiently effective, but arrhythmia continued. After administration of dopamine, norepinephrine and isoproterenol, we inserted a temporary transvenous pacemaker catheter, and the hemodynamics became stable by ventricular pacing. The operation was postponed. Subsequent cardiologic examination showed no ischemia. The atrioventricular block disappeared 7 hours after the induction of general anesthesia. We should be very careful with the anesthetic management of a patient with a complete right bundle branch block.

Aged↗

[Giant rheumatoid nodule causing simultaneous complete atrioventricular block and severe mitral regurgitation: a case report].

A 65-year-old female was first treated under a diagnosis of rheumatoid arthritis at the age of 62 years. Just after subcutaneous rheumatoid nodules appeared, she suddenly complained of shortness of breath and vomiting. The diagnosis was overt congestive heart failure with complete atrioventricular block and severe mitral regurgitation. She was treated with temporary pacing, and a permanent pacemaker was implanted 1 month later. She suffered recurrence of congestive heart failure and died 8 months later. Autopsy revealed a giant rheumatoid nodule located on the mitral valve and extending to the atrioventricular node. Presumedly this solitary giant nodule had induced complete atrioventricular block and severe mitral regurgitation.

Aged↗

[Complete atrioventricular block secondary to pulmonary embolism].

We describe a 73-year-old woman with a history of breast cancer and metastatic disease diagnosed in January 2002 (stable when we saw her) who was admitted for sudden dyspnea and presyncope. Complete atrioventricular block was documented, and a temporary pacemaker was implanted. Eight hours after admission she recovered sinus rhythm with left bundle branch block as seen in previous recordings. Computed tomography showed bilateral pulmonary thromboembolism. An electrophysiological study showed normal atrioventricular conduction. We suggest that in this patient, who had previous left bundle branch block, pulmonary thromboembolism may have induced transient right bundle branch block, which in turn caused atrioventricular block.

Aged↗

Mobitz II atrioventricular block due to infra-Hisian block and bundle branch extrasystoles.

An asymptomatic elderly male presented with complete right bundle branch block, left anterior fascicular block and Mobitz Type II second degree atrioventricular block. In addition, he was noted to have ventricular premature systoles. Electrophysiologic studies demonstrated two apparently different mechanisms for the second degree A-V block--infra-Hisian block and A-V block due to bundle branch extrasystoles arising in the affected right bundle branch. Concealed conduction of the bundle branch extrasystoles as the proximate cause of infra-Hisian block could not be excluded. However, both forms of A-V block were evidently dependent upon significant distal conduction system disease; this consideration was felt to warrant permanent pacemaker implantation.

Aged↗

Complete atrioventricular block following mediastinal irradiation: a report of six cases.

Complete atrioventricular block (AVB) following radiotherapy has been reported rarely, usually after high dose mediastinal irradiation for Hodgkin's disease or lung or breast carcinoma. We report six new cases of episodic complete infranodal AVB, requiring permanent pacemaker implantation. The mean age was 48-years old (ranging from 25-60) at the first Adams Stokes attack, mean delay was 12 years after irradiation (10-18), and mean radiation dose was 5,200 rads (4,000-6,500). All patients had abnormal interval electrocardiograms (right bundle branch block in two, left bundle branch block in three, alternating left and right bundle branch block in one). Electrocardiograms during the episode of AVB or Holter recordings were consistent with infranodal block in all patients; electrophysiological study performed in five patients confirmed infranodal AVB in four, and one was normal. Pericardial disease was constant, which included pericardial constriction in four patients. Two patients died after failure of pericardiectomy to improve congestive heart failure, due to epicardial, myocardial, and endocardial involvement. Noncardiac mediastinal lesions were present in four cases. Since this delayed complication may occur in patients of such age that the relation between the AVB and the chest irradiation is questionable, we propose the following etiologic criteria; high radiation dose (over 4,000 rads); delay of 10 years or more; abnormal interval tracings; pericardial involvement; and associated cardiac or mediastinal radiation-induced lesions.

Adult↗