Mechanism of intermittent bundle-branch block and paroxysmal atrioventricular block.
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Bundle-Branch Block↗
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Results for “Atrioventricular Block”
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[Round table discussion. Development of bundle branch blocks into complete atrioventricular blocks].
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Aged↗
[The unstable branch block in the complete atrioventricular block].
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Atrioventricular Block↗
Atrioventricular block.
The presentation of atrioventricular block in the critical care setting and the assessment parameters that the critical care nurse may use to aid in the determination of the severity of atrioventricular block are described. The underlying pathophysiology of atrioventricular block is examined to enhance the nurse's understanding of the rationale for intervention versus observation.
Critical Care↗
Understanding advanced concepts in atrioventricular block.
Not all atrioventricular blocks occur in the atrioventricular node. Understanding the physiological concept behind the various blocks makes recognizing the relevant ECG indications easier. Furthermore, the implications to patients are clear when healthcare providers understand the level of the block and the dangers the block may impose. Until a more accurately descriptive classification system of conduction blocks becomes universally accepted, the current labels will continue to be used. It is imperative that nurses, particularly those caring for cardiac patients, recognize and understand the ECG indications of various degrees of block.
Electrocardiography↗
Early and late advanced atrioventricular block in acute inferior myocardial infarction.
BACKGROUND: Advanced atrioventricular block is a frequent complication in patients with inferior acute myocardial infarction (AMI); in patients in hospital, it often occurs concurrently with other complications and is associated with high mortality. Very little information is available about early and late advanced atrioventricular block in inferior AMI. We hypothesized that the time of appearance of advanced atrioventricular block characterized by poor response to atropine requiring temporary pacemaker therapy may affect the prognosis of patients with inferior AMI. METHODS: We studied 51 patients with inferior AMI and advanced atrioventricular block characterized by poor response to atropine requiring temporary pacemaker therapy. According to pre-established electrocardiographic criteria and the time of appearance of the advanced atrioventricular block, patients were divided into two groups: an early block group consisting of 30 patients who developed advanced atrioventricular block during the first 24 h of inferior AMI, and a late block group consisting of 21 patients who developed advanced atrioventricular block after the first 24 h of chest pain. RESULTS: The groups were similar regarding age, coronary risk factors, frequency of right ventricular infarction, QRS score, atrial and ventricular rates, the time of return to first-degree atrioventricular block, cardiac arrhythmias, heart failure and mortality. The early advanced atrioventricular block group included a greater number of men than did the late group (P = 0.017). CONCLUSION: These data suggest that the time of appearance of advanced atrioventricular block does not affect the prognosis of hospital patients with inferior AMI.
Anti-Arrhythmia Agents↗
[First degree atrioventricular block caused by a calcified tumor of the atrioventricular septum].
First degree atrioventricular block occurred in a 69-year-old patient with a calcified atrioventricular septum tumour. The patient suffered several episodes of syncope and the only abnormality found in the routine clinical work-up was a remarkable first degree atrioventricular block. The echocardiogram, computed tomography (CT) and the magnetic resonance imaging (MRI) procedure showed a calcified tumour in the posterior part of the left ventricle, between the left atrium and left ventricle, just beneath the aortic root spreading to the interventricular septum. It was suggested that the first degree atrioventricular block was caused by the tumour. The symptoms were relieved by implantation of permanent cardiac pacemaker.
Aged↗
[Exercise-induced atrioventricular block].
Exercise-induced atrioventricular block in patients with normal atrioventricular conduction at rest is uncommon. Electrophysiologic studies have documented block distal to the atrioventricular node in these patients. Implantation of a permanent pacemaker is recommended because of a high incidence of subsequent symptomatic block. We report three symptomatic patients with exercise-induced atrioventricular block. Two patients showed a bundle branch block in the baseline electrocardiogram, suggesting a distal location of the block. In the remainder, with a normal QRS, the electrophysiologic study revealed AV block within the His bundle in response to atrial pacing.
Aged↗
Four cases of right-sided bundle-branch block and one case of atrioventricular block in three generations of a family.
Four cases of complete right bundle-branch block and one case of atrioventricular heart block, all occurring within three generations of the same family, are described. The 4 patients with bundle-branch block had no symptoms, whereas the patient with atrioventricular heart block suffered Adams-Stokes attacks from the age of 13 and died at 47 years of age. A 33-year-old man with bundle-branch block had a normal electrocardiogram at the age of 7, suggesting that inherited bundle-branch block does not necessarily manifest itself during the first years of life.
Adams-Stokes Syndrome↗
Intrinsic atrioventricular conductive function in horses with a second degree atrioventricular block.
The atrioventricular (AV) conductive functions were investigated before and after the pharmacological autonomic nervous blockade (PAB) through the electrophysiological study on six horses (AV block group) in which the dropped beats occurred more frequently (over 200 beats/24 hr) and on five horses (control group) in which the dropped beats occurred sporadically (under 200 beats/24 hr) or in which the arrhythmias were not recognized at all on the long-term electrocardiogram. As a result, AV conductivity, conduction time and refractoriness in the AV block group were lower, longer and higher, respectively, than those in the control group even after PAB. These results indicate the intrinsic AV conductive functions in the AV block group were withdrawing than in the control group.
Animals↗
Paroxysmal atrial tachycardia with second-degree atrioventricular block.
Paroxysmal atrial tachycardia with atrioventricular block usually indicates potentially dangerous overdigitalization, and serious heart disease is almost universally present. In this report, we describe a patient with a structurally normal heart who manifested spontaneously intra-atrial reentrant tachycardia with Wenckebach atrioventricular block in the absence of medications. In this patient, the longest atrial paced cycle length that induced atrioventricular nodal block was 390 ms, and the atrial cycle length during tachycardia ranged from 360 to 400 ms. The electrophysiologic study in our patient demonstrated that second-degree atrioventricular block during atrial tachycardia may occur in patients without structural heart diseases or taking any medication.
Electrocardiography↗
Recovery from congenital complete atrioventricular block.
Congenital complete atrioventricular block without any other intracardiac anomaly reverted to sinus rhythm at the age of 7 years. The girl had had heart failure and Adams-Stokes attacks when aged 1 year, requiring pacemaker implantation. Electrocardiography confirmed sinus rhythm for the first time at the age of 7 years. At the same time, a treadmill test yielded a normal tracing without any arrhythmias.
Adams-Stokes Syndrome↗
Long-term results of patients with congenital complete atrioventricular block.
Congenital complete atrioventricular block is an uncommon disorder with a prognosis which is usually favorable. The disorder is sometimes associated with syncope, sudden death or cardiac pacing. It is difficult to determine the patients at risk of sudden death. In this retrospective study, hospital records of children who had been admitted to the Hacettepe University Children's Hospital between 1970-1990 for evaluation of complete heart block were examined. The study population, consisting of 39 children, 27 males and 12 females, had electrocardiograms consistent with complete heart block. These patients, diagnosed as having congenital complete A-V block, had an otherwise normally structured heart, and were followed up for a period of from one month to 15 years. Age at diagnosis ranged from 27 days to 17 years (mean: 86.9 +/- 48 months). Of the 14 patients with symptoms (five with syncope, eight with exercise intolerance and one with presyncope), nine were paced electively and have done well. Clinical and laboratory features of the asymptomatic and symptomatic groups were compared to evaluate potential risk factors.
Adolescent↗
[Prognostic significance of second and third degree atrioventricular block in acute inferior wall myocardial infarction].
High degree atrioventricular block complicates inferior wall acute myocardial infarction in 10 to 15% of cases. Its significance is still controversial. In this study, we have analysed 152 observations of acute inferior wall myocardial infarction during hospitalisation period. The mean age of our patients is 60 years, 48.7% of them have received fibrinolytic treatment. Second or third degree atrioventricular block was detected in 33 cases (21.7%). Mortality is higher in inferior wall myocardial infarctions with atrioventricular block than in those without atrioventricular block (12% versus 2.5%, p < 0.05). Hemodynamic complications like cardiogenic shock due to the extension of the infarction to the right ventricle and left ventricle insufficiency are more frequent (18% versus 3.4%, p < 0.01 and 12% versus 3.5%, p < 0.01 respectively). It appears that the infracted mass of myocardium is larger in case of atrioventricular block, this is assessed by comparing the average value of the peak of creatine Kinase in the two groups with and without atrioventricular block (1534 IU versus 1096 IU, p < 0.02) and by considering the rate of low ejection fraction (EF < 40%) in each group (44.6% versus 16%, p < 0.01). In our study, we note that thrombolysis does not affect the incidence of atrioventricular block (19% and 24% in thrombolyed and not thrombolyzed patients respectively) but it seems that thrombolysis improves the outcome of these patients. The occurrence of atrioventricular block in acute inferior wall myocardial infarction is related to the presence of an important right coronary artery that is occluded, the recanalisation of this vessel leads often to rapid regression of the block that is no longer pejorative.
Acute Disease↗
[The ajmaline test in identifying patients at high risk of developing complete paroxysmal atrioventricular block].
In thirty-one patients (pts) with atrioventricular or intraventricular conduction disturbances, the Ajmaline test was used to evaluate the risk of evolution to complete atrioventricular block. Three groups of patients were identified: A = nine patients without history of syncope or dizziness; B = seventeen pts with history of syncope or dizziness but without evidence of complete atrioventricular block; C = five pts with recorded atrioventricular block and history of syncope or dizziness. All patients with symptoms (B-C groups) and with a positive Ajmaline test (i.e. HV greater than or equal to 90 msec.) were paced with regression of symptoms. All patients without symptoms (A group) and with a positive Ajmaline test (i.e. HV greater than or equal to 90 msec.) were not paced and did not progress to complete atrioventricular block in a follow-up period of two years. Our results confirm that the Ajmaline test is useful in demonstrating the cardiac origin of syncopal episodes, but an HV value of 90 msec, does not seem to be specific enough in identifying asymptomatic patients at risk of developing complete atrioventricular block.
Adult↗
Complete atrioventricular block during anesthesia.
PURPOSE: To describe a case of asymptomatic first degree atrioventricular block with a bifascicular block that progressed to complete atrioventricular block during anesthesia. This potentially fatal block was successfully treated with transesophageal ventricular pacing. CLINICAL FEATURES: A 67-yr-old man was scheduled for microvascular decompression of the right trigeminal nerve under general anesthesia. His preoperative ECG showed first degree atrioventricular block with complete right bundle branch block and left anterior hemiblock, but he had experienced no cardiovascular symptoms. Anesthesia was induced with sevoflurane 5%, and maintained with isoflurane 1.5-2% in oxygen. Fifteen minutes later in the left lateral decubitus position, the systolic arterial blood pressure suddenly decreased from 80 mmHg to 0 mmHg. Then, the ECG abruptly changed from sinus rhythm to complete atrioventricular block. The heart was unresponsive to drug therapy such as atropine 1.3 mg and isoproterenol 0.5 mg, or transcutaneous pacing but transesophageal pacing was successful. CONCLUSION: Asymptomatic first degree atrioventricular block with bifascicular block advanced to complete atrioventricular block during anesthesia. The block was successfully managed with transesophageal pacing.
Aged↗
Complete atrioventricular block, retrograde atrial activation and intra-atrial block.
A case of complete atrioventricular block, retrograde atrial activation, and intra-atrial block was reported. Inhomogeneous inhibition of the atrioventricular junction and the so-called summation of impulses may both act together to make retrograde conduction possible when third-degree atrioventricular block was present. In lead 2, P waves were dome-shaped, and in lead V1, P waves were biphasic; narrow and peaked P waves intermittently appeared, denoting third-degree intra-atrial block. The peaked P waves signified that the right atrium was activated while the left atrium was not depolarized.
Atrioventricular Node↗
Idiopathic acute myocarditis with complete atrioventricular block in a baby. Clinicopathological study of the atrioventricular conduction system.
A 17-month-old Japanese girl with an idiopathic acute myocarditis had symptoms of vomiting, slight fever, and liver enlargement, but no edema. Clinical diagnosis of acute myocarditis was not made until she had Stokes-Adams syndrome and electrocardiogram revealed complete atrioventricular block on the day of death. At autopsy, idiopathic acute myocarditis was detected diffusely in the right and left ventricles. Vomiting and liver enlargement were due to congestive heart failure. Serial sections of the atrioventricular conduction system revealed diffuse and severe acute inflammatory changes in the right bundle and the left bundle branches, especially in the terminal portions. Acute inflammation was focally noted in the atrioventricular node and the His bundle. The complete atrioventricular block probably followed the severe acute inflammation of the bundle branches. Our case suggest that idiopathic acute myocarditis may be underdiagnosed in babies, as there is no way to determine whether there is dyspnea and palpitation on exertion, and idiopathic fibrosis of conduction system with or without conduction disturbances in children and adults may be sequelae of healed myocarditis in babies.
Acute Disease↗