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PubMed2004

Transplacental fetal treatment improves the outcome of prenatally diagnosed complete atrioventricular block without structural heart disease.

BACKGROUND: Untreated isolated fetal complete atrioventricular block (CAVB) has a significant mortality rate. A standardized treatment approach, including maternal dexamethasone at CAVB diagnosis and beta-stimulation for fetal heart rates <55 bpm, has been used at our institutions since 1997. The study presents the impact of this approach. METHODS AND RESULTS: Thirty-seven consecutive cases of fetal CAVB since 1990 were studied. Mean age at diagnosis was 25.6+/-5.2 gestational weeks. In 33 patients (92%), CAVB was associated with maternal anti-Ro/La autoantibodies. Patients were separated into those diagnosed between 1990 and 1996 (group 1; n=16) and those diagnosed between 1997 and 2003 (group 2; n=21). The 2 study groups were comparable in the clinical presentation at CAVB diagnosis but did differ in prenatal management (treated patients: group 1, 4/16; group 2, 18/21; P<0.0001). Overall, 22 fetuses were treated, 21 with dexamethasone and 9 with beta-stimulation for a mean of 7.5+/-4.5 weeks. Live-birth and 1-year survival rates of group 1 were 80% and 47%, and these improved to 95% for group 2 patients (P<0.01). The 21 patients treated with dexamethasone had a 1-year survival rate of 90%, compared with 46% without glucocorticoid therapy (P<0.02). Immune-mediated conditions (myocarditis, hepatitis, cardiomyopathy) resulting in postnatal death or heart transplantation were significantly more common in untreated anti-Ro/La antibody-associated pregnancies compared with patients treated with steroids (0/18 versus 4/9 live births; P=0.007). CONCLUSIONS: A standardized treatment approach, including transplacental fetal administration of dexamethasone and beta-stimulation at heart rates <55 bpm, reduced the morbidity and improved the outcome of isolated fetal CAVB.

Adrenergic beta-Agonists↗
PubMed1992

[Permanent variable frequency cardiac pacing: which patients with chronic complete atrioventricular block profit most?].

The authors examined 27 patients with chronic complete atrioventricular block (AVIII) and an implanted pacemaker with rate responsive pacing (RRP), controlled by atrial frequency (DDD stimulation--19 patients) or the length of the QT interval (VVIR pacing--8 patients). The loading test in AVIII ventricular stimulation 70/min (VVI 70) and RRP proved a more than double asset of MKP in RRP, as compared with VVI 70 (55.5 +/- 43.3% vs. 24.3 +/- 34.1%, p less than 0.001). The difference was greater in acquired than in congenital AVIII (27.7 +/- 18.5% vs. 8.4 +/- 4.1%, p less than 0.002) and in patients where the maximum heart rate on VVI did not exceed 70/min, as compared with the remainder (29.3 +/- 19.1% vs. 12.7 +/- 8.1%, p less than 0.002). The difference of MPK in RRP and VVI 70 was inversely correlated with MPK on VVI 70 (r = -0.412, p less than 0.03). MPK on AVIII and MTF on VVI 70 (r = -0.386, p less than 0.05). RRP in patients with AVIII thus causes a double increase of MPK, as compared with VVI pacing. A greater asset can be expected in patients with acquired AVIII, with a lower working capacity and heart rate recorded during the loading test before implantation.

Adolescent↗
PubMed2002

[Primary cardiac lymphoma presenting with complete atrioventricular block. Case report and review of the literature].

Primary cardiac lymphoma is very rare and clinical symptoms of cardiac involvement are unusual. The development of conduction defects as the first symptom of cardiac involvement is very uncommon. We report the case of a 57-year-old woman with syncope and complete atrioventricular block due to large B-cell primary cardiac lymphoma. The patient showed a refractory pericardial effusion. Transthoracic echocardiography revealed the presence of a mass in the pericardial space. The diagnosis of diffuse large B-cell lymphoma was made following open-chest biopsy of the heart. The clinical presentation of and the diagnostic approach to primary cardiac lymphoma are discussed. Atrioventricular block and refractory unexplained pericardial effusion and/or the existence of a cardiac mass should arouse the clinical suspicion of this rare malignancy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1987

Atrial fibrillation with high degree atrioventricular block masquerading as ventricular fibrillation masquerading as asystole during cardiac arrest.

Ventricular fibrillation (VF) can masquerade as asystole. We report a 54-yr-old male in cardiac arrest who, on surface ECG, appeared to be in VF or asystole. A bedside intracardiac recording using a transmyocardial pacing wire showed the true rhythm to be atrial fibrillation (AF) with high grade atrioventricular block. AF with a high degree block can masquerade as VF, which simultaneously masquerades as asystole, and can be correctly diagnosed by bedside intracardiac monitoring. Patients who have a flat line rhythm which may represent asystole, fine ventricular fibrillation, or atrial fibrillation with a high degree atrioventricular block may warrant a trial of electrical countershock, high-dose atropine, or transthoracic pacing.

Arrhythmias, Cardiac↗
PubMed1991

Arrhythmogenic activities of antiarrhythmic drugs in conscious hypokalemic dogs with atrioventricular block: comparison between quinidine, lidocaine, flecainide, propranolol and sotalol.

In order to create and evaluate a model sensitive to QT-dependent proarrhythmic effects of drugs, a long QT syndrome was produced in chronically instrumented dogs with bradycardia and hypokalemia. Bradycardia (mean cycle length: 1495 +/- 78 msec) was provided by permanent atrioventricular block and hypokalemia (K+ = 2.6 +/- 0.05 mmol/l) by high doses of diuretics. To evaluate that model, six of these conscious dogs were subjected to quinidine, flecainide, lidocaine, propranolol and sotalol infusions. In crossover design, drugs were infused i.v. at rates allowing stable and nontoxic drug plasma levels during the experiment. Four-lead ECGs were recorded for arrhythmias for 30 min before (base line) and 75 min after onset of infusion. Ventricular cycle length was increased dramatically by sotalol, lidocaine and propranolol (+618 +/- 192, +388 +/- 125 and +329 +/- 114 msec, respectively) and QT interval was increased by sotalol, quinidine and flecainide (+56 +/- 8, +31 +/- 7.9 and +20 +/- 5.7 msec, respectively). Quinidine and sotalol, but not flecainide, propranolol or lidocaine, exhibited significant arrhythmogenic activities. During quinidine infusion, most dogs exhibited some ventricular arrhythmias whose most severe forms were runs of ventricular tachycardia. These arrhythmias were suppressed by pacing at high rates. During sotalol infusion, five out of six dogs exhibited typical "torsades de pointes." This incidence was not related to the slowing effects of sotalol on idioventricular pacemakers, because a similar incidence was obtained in five complementary dogs paced at 40 bpm. It could be related to dose, because torsades de pointes occurred only once in another group of five dogs receiving half the dose used in the controlled study. Only quinidine and sotalol, but not propranolol, flecainide or lidocaine, are clinically associated to torsades de pointes. They were also the only drugs associated with proarrhythmic events in the present study, a fact suggesting that QT-dependent arrhythmogenic effects of drugs can be reliably evaluated in conscious hypokalemic dogs with complete atrioventricular block.

Animals↗
PubMed2006

Long-term bradycardia caused by atrioventricular block can remodel the canine heart to detect the histamine H1 blocker terfenadine-induced torsades de pointes arrhythmias.

Although a second-generation histamine H(1) blocker terfenadine induced torsades de pointes (TdP) arrhythmias in patients via the blockade of a rapid component of delayed rectifier K(+) current (I(Kr)), such action of terfenadine has not been detected in previous animal models. We analysed the potential of the canine persistent atrioventricular block heart, a new in vivo proarrhythmia model, to detect a torsadogenic effect of terfenadine of an oral dose of 3 or 30 mg kg(-1). The doses can provide therapeutic to supra-therapeutic plasma concentrations as an anti-histamine. In 2 weeks of bradycardiac heart model, there were no significant changes in any of the electrocardiogram parameters after the administration of both doses of terfenadine. In 4-6 weeks of bradycardiac heart model, the low dose of terfenadine hardly affected any of the electrocardiogram parameters except that it induced TdP in one out of six animals. The high dose significantly decreased the atrial rate and ventricular rate, prolonged the QT interval, and induced TdP in five out of six animals. Moreover, temporal variability of repolarization increased after the high-dose administration. These results suggest that long-term bradycardia caused by atrioventricular block can remodel the canine heart to detect terfenadine-induced TdP.

Animals↗
PubMed1993

[Intermittent ventricular pre-excitation in the presence of total atrioventricular block].

An 8 year old child suffering from asthenia and complete atrioventricular block, probably congenital. During the tread-mill test there was a sudden electrocardiogram change to a ventricular preexcitation pattern. Besides this rare association, we emphasize the importance of the autonomic balance over the accessory pathway's electrophysiological properties. The appearance of a latent accessory pathway might be a substitutive mechanism to counterbalance the serious impairment of physiologic atrioventricular conduction.

Child↗
PubMed1986

[High prevalence of 2d and 3d grade atrioventricular block in patients with acute myocardial infarct and right ventricular ischemic involvement].

43 consecutive patients with acute inferior myocardial infarction (IMI) were evaluated with 12-lead electrocardiogram plus four additional right precordial lead V3R, V4R, V5R, V6R and equilibrium gated radionuclide angiography (EGRA) to detect ischemic right ventricular involvement. All patients were continuously monitored on the average 6 days; 11 of 43 patients had an episode of second or third degree atrioventricular block. Ischemic right ventricular involvement was diagnosed by electrocardiographic criteria in 60%, and by scintigraphic criteria in 70% of 43 patients with IMI. Utilization of electrocardiogram and EGRA for diagnosis of right ventricular involvement permit us to identify a subgroup of patients with IMI at high risk of developing second or third atrioventricular block (38% with ecg criteria and 33% with radionuclide criteria respectively) as regards those without right ventricular involvement (6% and 8%).

Adult↗
PubMed2006

Ruptured sinus of valsalva and complete atrioventricular block complicating fulminant course of infective endocarditis: a case report and literature review.

Patients with infective endocarditis usually developed persistent fever and heart failure, especially when the valve structures are invaded and destroyed. Persistent bacteremia often leads to severe sepsis or overwhelming septic shock. Septic emboli from the vegetation will possibly result in systemic thromboembolism with multiple organ infarction. Patients with infective endocarditis have been reported to present with either ruptured sinus of Valsalva or complete atrioventricular block. However, both of these serious complications occurring in a single patient is rare. In this case report, we present a 54-year-old man with a previous history of alcoholic cirrhosis and chronic renal failure who suffered from a fulminant course of infective endocarditis. Simultaneously, ruptured sinus of Valsalva and complete atrioventricular block further complicated the preexisting septic shock and multiple organ failure.

Aortic Rupture↗
PubMed1999

[Complete atrioventricular block during temporal lobe epilepsy. Apropos of a case].

The authors report the case of a 37 years old woman with no previous medical history, admitted to hospital for investigation of unexplained syncope, sometimes associated with generalised fits. After standard non-invasive cardiovascular investigations, no diagnosis could be made. The tilt test induced a minor syncopal episode without reproducing the clinical symptoms. In view of the discordance between the induced and spontaneous symptoms, a neurological opinion was requested. During the recording of an electroencephalogram, syncopal atrioventricular block was observed, preceded by auditory hallucinations, reproducing exactly the clinical symptoms. Analysis of the sequence of events showed the conduction defect to arise after the onset of the epileptic fit, indicating a diagnosis of syncopal complete atrioventricular block complicating cryptogenic temporal epilepsy, and requiring specific treatment. This case illustrates the importance of close collaboration between cardiologists and neurologists in the management of cases of unexplained syncope.

Adult↗
PubMed1998

Atrioventricular block occurring several months after radiofrequency ablation for the treatment of atrioventricular nodal re-entrant tachycardia.

Atrioventricular (AV) block following radiofrequency (RF) ablation for the treatment of AV nodal re-entrant tachycardia (AVNRT) is a rare but well recognised complication of the procedure--the reported incidence ranges from 1% to 21%. Almost all cases of AV block occur during or shortly after the procedure, are transient, and recover quickly. Two patients (a 22 year man and a 72 year old woman) with symptomatic AV block occurring several months after slow pathway RF ablation, requiring permanent pacemaker implantation, are described. Both patients had had several 24 hour Holter recordings before the procedure, and in neither case was there any evidence of intermittent or persistent AV block. This is a rare complication with no definitive predictors; however, all efforts should be made to exclude AV block in patients presenting with suggestive symptoms following RF ablation. With the wide use of RF ablation for the treatment of AVNRT, more cases are likely to occur. A registry should allow documentation of the incidence of this complication.

Adult↗
PubMed2006

Fetal ECG: a novel predictor of atrioventricular block in anti-Ro positive pregnancies.

OBJECTIVE: Approximately 2.8% of pregnancies are Ro/La antibody positive. 3-15% of fetuses develop complete heart block (CHB). First-degree atrioventricular heart block (1 degrees AVB) is reported in a third of Ro/La fetuses but as most have a normal postnatal ECG this may reflect inadequacies of Doppler measurement techniques. METHODS: Comparison was made between mechanical (mPR) and electrical (ePR) intervals obtained prospectively using Doppler and non-invasive fetal ECG (fECG) in 52 consecutive Ro/La pregnancies in 46 women carrying 54 fetuses in an observational study at a fetal medicine unit. 121 mPR and 37 ePR intervals were recorded in 49 Ro/La fetuses. Five were referred with CHB and excluded. ePR was measured successfully in 35/37 (94%) and mPR was measured in all cases. 1 degrees AVB was defined as PR >95% CI. Logistic regression predicted abnormal final fetal rhythm from first mPR or ePR. RESULTS: The ePR model gave 66.7% sensitivity (6 of 8 final abnormal fetal rhythm cases were predicted correctly in fetuses >20 weeks) and 96.2% specificity. mPR gave 44.4% sensitivity (4 of 9 cases) and 88.5% specificity. Z scores for ePR (zPR) were calculated from 199 normal fetuses. The area under the receiver operator characteristic (ROC) curve was 0.88 (95% CI, 0.754 to 1.007). A cut-off of 1.65 gave a sensitivity of 87.5% and specificity of 95% for those with prolonged and normal ePR intervals, respectively. CONCLUSION: zPR is better than mPR at differentiating between normal and prolonged PR intervals, suggesting that fECG is the diagnostic tool of choice to investigate the natural history and therapy of conduction abnormalities in Ro/La pregnancies.

Adolescent↗
PubMed1991

Effects of atrioventricular block on ventricular fibrillation threshold in dog.

The effects of complete atrioventricular block (CAVB) on ventricular vulnerability were studied 1 week after a transcatheter electrical ablation of the AV junction in 18 closed-chest dogs. All dogs exhibited CAVB and a stable ventricular escape rhythm with a mean cycle length of 1795 +/- 600 ms. Although QT interval during CAVB was significantly prolonged compared with that during the sinus rhythm, QTc interval was significantly shortened. The ventricular fibrillation threshold was significantly elevated after creation of the block (from 9.35 +/- 2.28 to 12.3 +/- 3.69 mA, p less than 0.01). Thus, CAVB which is not associated with QTc prolongation would be even less likely to play an important role in producing ventricular fibrillation presumably including torsades de pointes or polymorphous ventricular tachycardia.

Animals↗
PubMed2005

Successful perinatal management of a very low birthweight infant with congenital complete atrioventricular block.

We report a very low birthweight infant with congenital complete atrioventricular block (CCAVB) who underwent delayed implantation of a permanent pacemaker without temporary pacing. The female infant was born at 30 weeks gestation and weighed 1422 g. After birth, the infant showed respiratory failure due to pleural effusion and respiratory distress syndrome at birth. The heart rate ranged between 50 and 55 bpm. The chest x-ray demonstrated dilated heart, but echocardiogram showed good systolic ventricular function. Respiratory failure was resolved after supportive treatment without temporary pacing. Mild heart failure due to low heart rate persisted, but was successfully managed by conventional heart failure therapy combined with nasal continuous positive airway pressure. She achieved a body weight gain to 1856 g at the age of 49 days and underwent implantation of a permanent pacemaker. We conclude that it is important to determine the timing of both delivery and pacemaker implantation for successful perinatal management of infants with CCAVB.

Adult↗
PubMed1993

Early afterdepolarization in a patient with complete atrioventricular block and torsades de pointes.

We present a patient with complete atrioventricular block and torsades de pointes in whom early afterdepolarization (EAD) was demonstrated in right ventricular monophasic action potentials (MAPs). In an emergency situation, MAPs were recorded after the suppression of torsades de pointes by magnesium injection. EADs were observed at three out of five right ventricular sites during escape rhythm. Thus, magnesium abolished the tachycardia without shortening the QT interval and probably without suppressing EAD. Right ventricular pacing and the injection of lidocaine (50 mg) suppressed EAD and shortened the QT interval.

Action Potentials↗