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Results for “Atrioventricular Block”

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At least 91 records · Page 5Linked to original sources

PubMed1990

Persistent functional atrioventricular block in two patients with prolonged QT intervals: elucidation of the mechanism of block.

This article describes two infants with prolonged QT interval and intermittent second-degree atrioventricular block. An asymptomatic 14-month-old child with persistent 2:1 atrioventricular conduction since birth underwent electrophysiology study including measurements with a contact monophasic action potential catheter. During 2:1 conduction, atrioventricular block occurred distal to the site of the His-bundle recording. Monophasic action potential duration was closely related to prior RR intervals. Single premature atrial or ventricular depolarizations during 1:1 conduction followed by a pause, lead to monophasic action potential prolongation and subsequent 2:1 atrioventricular conduction, which was perpetuated by the resulting long RR intervals. Paired premature ventricular contractions or short bursts of ventricular pacing elicited monophasic action potential shortening and subsequent 1:1 atrioventricular conduction that was perpetuated by the resulting short RR intervals. A second infant presented at birth with a prolonged QT interval, ventricular tachycardia, and episodes of second-degree atrioventricular block with persistent 2:1 atrioventricular conduction. The atrioventricular block was repeatedly elicited by single premature ventricular contractions and terminated by ventricular couplets. We conclude that the atrioventricular block in both patients is functional in nature and results from the interrelationships between ventricular rate, action potential duration, and His-Purkinje system refractoriness.

Action Potentials↗

PubMed1982

Reversible chronic acquired complete atrioventricular block.

The return of atrioventricular conduction is reported in a case after nearly four years of complete acquired heart block. After recovery from atrioventricular block, right bundle branch block persisted, but P-R interval and H-V interval were normal. Three months later a relapse of second degree infranodal atrioventricular block was noted. A short review of similar cases from the literature is given.

Aged↗

PubMed1997

Frequency and prognostic significance of high-degree atrioventricular block in patients with a first non-Q-wave acute myocardial infarction. The SPRINT Study Group. Second Prevention Reinfarction Israeli Nifedipine Trial.

Patients with a first non-Q-wave acute myocardial infarction with high-degree atrioventricular block were compared with patients without atrioventricular block. In-hospital complications and mortality were significantly higher among patients with atrioventricular block; atrioventricular block emerged as an important prognostic predictor of early mortality in these patients.

Age Factors↗

PubMed1977

[Electrocardiographic classification of total atrioventricular block].

The introduced systematization of full atrioventricular blocks is a new method of analysis of ECG data in such patients. Singling out the arrhythmic form of a full atrioventricular block serves as a means of early diagnosis of the possible complications of making the prognosis of the patient's state, and as a method of choice of surgical or medical treatment; it permits timely implantation of a pacemaker, reduces the period of examination and therapy, which ensures an economic effect.

Aged↗

PubMed1979

[Importance of sequential atrioventricular pacing in obstructive myocardiopathy with atrioventricular block].

A case of atrioventricular block (AVB) complicating hypertrophic obstructive cardiomyopathy is reported and analysed with respect to the results of cardiac catheterisation. The installation of 2nd degree AVB was associated with an increase of the intraventricular pressure gradient from 36 to 128 mmHg. This aggravation was related to the lenghtening of diastole which lowered the aortic diastolic pressure and allowed a more forceful ventricular contraction with a reduction in the calibre of the intraventricular stenosis. The sudden lenghtening of diastole also led to an increased contractility of the following systole. In complete AVB the increased gradient was related to a reduction in ventricular volume secondary to the loss of atrial systole. The 33 mmHg pressure gradient disappeared when spontaneous atrial systole or an atrial systole provoked by sequential atrioventricular pacing preceded ventricular contraction. Sequential atrioventricular pacing would seem to be the most appropriate pacing technique in hypertrophic obstructive cardiomyopathy complicated by complete AVB.

Aged↗

PubMed2001

Atrioventricular block in a newborn with acquired long QT syndrome.

We report a case of 2:1 atrioventricular block associated with acquired long QT syndrome. A newborn presented to our neonatal intensive care unit with intermittent bradycardia due to 2:1 atrioventricular block. Initial evaluation showed QT prolongation and significant electrolytic abnormalities. After correction of the electrolytic imbalance, the QT interval normalized and atrioventricular block resolved. Compared to congenital long QT syndrome with 2:1 atrioventricular block, acquired long QT syndrome with comparable atrioventricular block has a benign prognosis, provided treatment is initiated quickly.

Electrocardiography↗

PubMed1982

Beat-by-beat control of cardiac output in awake dogs with atrioventricular block.

In dogs with atrioventricular block and implanted ascending aortic flow probes, cardiac output can be controlled on each beta. The procedure is implemented through on-line use of a digital computer. The algorithm has three steps: 1) aortic flow is measured and integrated to give stroke volume; 2) at the end of ejection, the program computes how long the current beat must be to keep cardiac output at a target level; and 3) the ventricle is stimulated at the proper time. Cardiac output can be controlled over a range of 60-110% of normal in a resting dog. This range can be expanded by combining hemorrhage or volume infusion with the control procedure.

Animals↗

PubMed2005

Correlation between 25 element contents in mane hair in riding horses and atrioventricular block.

The influence of atrioventricular block (AV-block) on the trace elemental status in a horse hair was studied. The particle-induced X-ray emission (PIXE) method has provided a reliable, rapid, easy, and relatively inexpensive diagnostic method. Twenty-five elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Sr, Ti, Y, and Zn) in mane hair and serum were measured by the PIXE method. A horse hair with first- and second-degree AV-block contained significantly greater amounts of Br, Ca, Sr, and Zn than those of horses without electrocardiographic abnormalities, whereas there was no significant differences in the elemental contents of the serum of the both groups. Those results in contents of a horse hair suggest that the evaluation of the degree of ionic imbalance by this method might be used to predict the susceptibility of a horse to heart disease much before symptoms appear.

Animals↗

PubMed1984

Pathology of atrioventricular block.

This article provides a summary of the types of congenital atrioventricular block and the various acquired diseases in which atrioventricular block may occur. Some lesions found in atrioventricular block are illustrated.

Aortic Valve Stenosis↗

PubMedDate not supplied

[Symptomatic congenital complete atrioventricular block--a medical challenge].

Congenital complete atrioventricular block is a rare entity. The association between this disease, maternal connective tissue disease and maternal antibodies [anti-Ro (SS-A) resp. anti-La (SS B)] is well known. Diagnosis can be made by means of fetal Doppler-echocardiography by the 16th week of gestation. In our case diagnosis was established in the 21st week of gestation. Ventricular rate was 55/min, atrial rate 70/min. There were no signs of fetal hydrops. There were no signs of maternal connective tissue disease, but anti-Ro and anti-La antibodies could be detected. The mother was treated with steroids from the time of diagnosis until the end of pregnancy. Altogether 9 Doppler-echocardiographic studies were performed. A recurrence of normal rhythm did not occur. A slow but continuous decrease of atrial and ventricular rate was observed. Interestingly, there was no development of fetal hydrops until the very end of pregnancy when the fetal heart rate reached a low of 28 beats per minute. We speculate, that the therapy with steroids might have played an important role in the prevention of early hydrops. At the onset of fetal hydrops delivery should be considered. In symptomatic complete atrioventricular block we prefer the implantation of a permanent pacemaker system immediately after birth. Efficient care for the fetus resp. the newborn can only be achieved through well planned cooperation.

Adult↗

PubMed1995

The value of the clinical history in the differentiation of syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope.

BACKGROUND: The present study was undertaken to identify and quantitate the symptoms associated with neurocardiogenic syncope, syncope due to ventricular tachycardia, and syncope resulting from atrioventricular block. PATIENTS AND METHODS: Eighty patients referred for evaluation of syncope in whom a diagnosis of neurocardiogenic syncope, atrioventricular block, or ventricular tachycardia was established were studied. Each patient was interviewed using a standard questionnaire. The clinical histories were then compared to identify which variables best differentiated the cause of syncope. RESULTS: The clinical histories of patients with syncope due to ventricular tachycardia and atrioventricular block were similar. Only age, the duration of prodromal symptoms, diaphoresis prior to syncope, and fatigue following syncope differed. In contrast, the clinical history in patients with neurocardiogenic syncope differed greatly from that obtained in patients with syncope due to atrioventricular block or ventricular tachycardia. Features of the clinical history that were predictive of syncope due to atrioventricular block or ventricular tachycardia were male sex, age > 54 years, < or = 2 episodes of syncope, and a duration of warning of < or = 5 seconds. Features of the clinical history predictive of syncope not due to ventricular tachycardia or atrioventricular block were palpitations, blurred vision, nausea, warmth, diaphoresis, or lightheadedness prior to syncope, and nausea, warmth, diaphoresis, or fatigue following syncope. CONCLUSIONS: The results of this study identify and compare the features of the clinical history obtained in patients with syncope due to ventricular tachycardia, atrioventricular block, and neurocardiogenic syncope and demonstrate that the clinical history is of value in distinguishing patients with these three causes of syncope.

Adult↗

PubMed1984

Pacemaker dependence in transient high-grade atrioventricular block.

In a prospective study 16 patients who had been given a pacemaker because of symptomatic high-grade atrioventricular block and whose conduction had been recovered were checked for their dependence on the pacemaker. During a follow-up time ranging from 32 to 158 months (median 62 months) six patients proved to be dependent on the device owing to the development of recurrent stable high-grade atrioventricular block. The subsequent return of atrioventricular block was evidently not associated with etiology, age, sex, ECG-pattern or length of follow-up period. Five additional patients equipped with a bradycardia-indicating pacemaker all proved to be pacemaker-dependent after a follow-up time ranging from 1-20 months (median 7 months), even though atrioventricular conduction had recovered and its presence had been confirmed at regular outpatient checks. It is thus evident that the conventional clinical methods are of limited value for examining the course of conduction defect and assessing the prognosis for patients whose spontaneous cardiac activity has returned after periods of symptomatic high-grade atrioventricular block. When a bradycardia-indicating pacemaker was furnished, pacemaker dependence was demonstrated in most of the patients whose atrioventricular conduction had recovered. This confirms that pacing introduced because of symptomatic high-grade atrioventricular block should not be discontinued even if a conducted heart rhythm has been established and maintained for long periods.

Aged↗

PubMedDate not supplied

Third-degree atrioventricular block in 21 cats (1997-2004).

The effect of 3rd-degree atrioventricular block on long-term outcome in cats is unknown. Clinical findings and long-term outcome of 21 cats with 3rd-degree atrioventricular block were studied retrospectively. Median age of cats studied was 14 years (range 7-19 years). Presenting signs included respiratory distress or collapse, but 6 cats had no clinical signs of disease. Eight cats had congestive heart failure (CHF) at the time that 3rd-degree atrioventricular block was detected. Heart rates ranged from 80 to 140 beats per minute (bpm; median 120 bpm) with no difference in heart rate between cats with and those without CHF. Eleven of 18 cats that had echocardiograms had structural cardiac disease, and 6 cats had cardiac changes consistent with concurrent systemic disease. No atrioventricular nodal lesions were detected by echocardiography. One cat had atrioventricular nodal lesions detected on histologic examination. Median survival of 14 cats that died or were euthanized was 386 days (range 1-2,013 days). Survival did not differ between cats with or without CHF or between cats with or without structural cardiac disease. Thirteen cats with 3rd-degree atrioventricular block survived > 1 year after diagnosis, regardless of presenting signs or underlying cardiac disease. Third-degree heart block in cats is often not immediately life threatening. Survival was not affected by the presence of underlying heart disease or congestive heart failure at the time of presentation. Even cats with collapse might survive > 1 year without pacemaker implantation.

Animals↗

PubMed1996

Cost benefit analysis of single and dual chamber pacing for sick sinus syndrome and atrioventricular block. An economic sensitivity analysis of the literature.

The benefits of dual (DDD) over single chamber pacing (VVI) have been demonstrated in haemodynamics, exercise capacity, quality of life and reduced complications in atrioventricular block and sick sinus syndrome. The literature was reviewed to provide complication rates for dual and VVI pacing. Cost calculations were based on United Kingdom 1991 prices. Over a 10-year period, a computer model calculated the incidence and prevalence of atrial fibrillation, stroke, permanent disability, heart failure and mortality in six patient categories: sick sinus syndrome paced VVI, sick sinus syndrome upgraded to DDD, sick sinus syndrome paced DDD from outset, atrioventricular block paced VVI and those upgraded to DDD and atrioventricular block paced initially DDD. Calculations were based on intention to treat. The 10 year survival with DDD vs VVI pacing was 71% vs 57% in sick sinus syndrome and 61% vs 51%, respectively, in atrioventricular block. In both indications the prevalence of heart failure in the 10 year survivors was 60% lower with DDD pacing. In sick sinus syndrome patients paced VVI, 36% had severe disability while only 8% experienced this with DDD pacing. For atrioventricular block the figures were, respectively, 22% vs 3%. The difference in 10 year cumulative cost between VVI and DDD is 13 times the purchase price of a VVI pulse generator for sick sinus syndrome and 7 times for atrioventricular block. In the third year after implantation the cumulative costs of DDD were lower than for VVI for both indications. Dual chamber pacing for both indications, sick sinus syndrome and atrioventricular block, is both clinically and cost effective.

Atrial Fibrillation↗

PubMed1994

[Inferior wall myocardial infarction and atrioventricular block; angiography and prognosis].

This study was based on 42 cases of 2nd or 3rd degree atrioventricular block out of 292 cases of inferior wall myocardial infarction. The criteria of selection were monitoring in the intensive care unit during the acute phase, selective coronary angiography in the first 48 hours to 5 days, and regular clinical follow-up during the first year after infarction. The conduction defect was either immediately recorded on the first ECG, delayed (between the 12th and 24th hour) or late (after the 3rd day). These 42 inferior wall infarcts with atrioventricular block (incomplete in 14 and complete in 28 cases) differed from inferior infarction without block by: - the severity of the clinical signs during the acute phase (35% with cardiac failure, 19% with cardiogenic shock); - the severity of the coronary lesions (71.4% with triple vessel disease in infarction with atrioventricular block compared with 32% in those without block, p < 0.02); - the prevalence of the association of > 70% stenosis of the right coronary and left anterior descending arteries; - the alteration of left ventricular function (53% patients with atrioventricular block had ejection fraction of under 30%); - the severity of these infarcts was not related to the atrioventricular block which regressed in 95% of cases but to the severity of the coronary disease, the left ventricular dysfunction and the advanced age of the patients (72.3 +/- 8 years).

Aged↗

PubMed1981

Sinus node recovery time in patients with complete atrioventricular block.

In 30 symptomatic patients with complete atrioventricular block, sinus node recovery time was measured in order to establish the incidence of sinus node dysfunction. Prolonged corrected sinus node recovery time (more than 560 msec) was found in seven cases (23%). Sinus node recovery time expressed as percentage change of the basic cycle length exceeded the upper limit of normal (more than 170%) in nine cases (30%). The mean value of these parameters was 563 msec and 179%, respectively. The study shows that sinus node dysfunction frequently coexists with complete atrioventricular block.

Adult↗

PubMed1996

Complete infrahisian atrioventricular block after endocavitary shock delivered by an automatic implantable cardiac defibrillator.

Transient reproducible complete infrahisian atrioventricular block occurred after endocavitary cardioversion of ventricular tachycardia and ventricular fibrillation by an automatic implantable cardiac defibrillator in a patient with left bundle branch block and baseline borderline H-V interval. Six months later, a permanent complete atrioventricular block occurred after repetitive endocavitary shocks. Several hypothetical mechanisms may explain this infrahisian atrioventricular block a "fatigue" phenomenon of the His-Purkinje system, vagally mediated atrioventricular block, and/or ablation of the His conduction system. The last seems to be the most probable, which would justify implantation of an automatic implantable cardiac defibrillator with backup pacing in all patients, especially in the presence of bundle branch block.

Adult↗

PubMed1990

Advanced atrioventricular block and complete left bundle branch block in a case of Takayasu's aortitis.

A 56-year-old woman, who had received an aortic valve replacement suffered from complete left bundle branch block and advanced atrioventricular block. On the basis of marked systemic inflammatory findings on admission and histopathological findings on previous cardiac surgery, this patient was considered to have conduction disturbances that were a consequence of myocardial involvement of Takayasu's aortitis. The conduction disturbances improved rapidly after treatment with steroids.

Aortic Arch Syndromes↗