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A case of complete heart block is presented in a patient whose brothers were known to have ankylosing spondylitis. Uveitis and sacro-iliitis are well recognised among HLA-B27-positive siblings of ankylosing spondylitis. However, heart block is a rare occurrence as a sole presentation in siblings of patients with ankylosing spondylitis.
We report a case of Lyme myocarditis presenting solely as complete heart block in a previously healthy 32-year-old white man. Indium cardiac antimyosin scan showed diffuse uptake (2+, on a scale of 0 to 4+) during the acute phase of the illness. The electrocardiogram and the indium cardiac antimyosin scan were normal 6 weeks after completion of tetracycline and prednisone treatment. Lyme carditis should be considered in the differential diagnosis of complete heart block of unclear origins, even in patients presenting without other signs or symptoms suggestive of Lyme disease.
An 18-year-old boy with congenital complete heart block presented with recurrent syncope following insertion of a rate-responsive dual-chamber pacemaker. Head-up tilt testing demonstrated a primary vasodepressor response with severe hypotension and reproduction of symptoms. Treatment with fludrocortisone and salt abolished symptoms, and repeat tilt testing was negative.
The cardiac conduction system was examined in 2 hearts which had repair of atrioventricular septal defect. The first was from a child known to have had a prolonged P-R interval and the second was from a girl who developed complete heart block before submission to surgery. The atrioventricular conduction axis was histologically discontinuous in the first case, but preserved and surrounded by hemorrhage in the second case. This study draws attention to the inherent vulnerability of the cardiac conduction axis which must also be recognized before surgical intervention.
We report the presence of complete heart block in a girl whose mother has anti-Ro antibodies and is suffering from systemic lupus erythematosus with Sjögren's syndrome. HLA antigens studies in the two patients support the hypothesis described recently that HLA DR3 is responsible for the production of anti-Ro antibodies and not for the phenotypic expression of the tissue injury.
Two cases of congenital complete heart block arising during pregnancy were observed in association with a circulating maternal autoantibody to the soluble ribonucleoprotein Ro(SS-A). Neither mother had clinical evidence of Sjögren's syndrome or systemic lupus erythematosus usually associated with anti-Ro. However, both had a previous history of first-trimester abortion and laboratory evidence of autoimmunity, and one gave a history of sialadenitis. Maternal anti-Ro antibodies may be predictive of infantile heart block when present in pregnant women with overt or suspected multisystem autoimmune disease.
The effect of beta-adrenergic blockade (propranolol) on exercise performance was studied in 15 patients (12 men and 3 women, mean age 70 years) with complete heart block treated with a ventricular-inhibited pacemaker (VVI). In a double-blind procedure, the patients were randomly given either 0.1 mg/kg of propranolol or saline solution i.v. before a first exercise test and vice versa before a second test. The interval between the tests was 24 hours. Nine patients were in sinus rhythm, 4 patients had atrial flutter, and 2 others had atrial fibrillation. The exercise capacity was on an average 11% lower with propranolol than with placebo (p less than 0.001). The most marked reductions (20 and 33%) were found in the two patients with atrial fibrillation. The atrial rate in patients with sinus rhythm was significantly lower with propranolol than placebo both at rest (68 vs. 83 beats/min, p less than 0.001) and at maximal work load (91 vs. 141 beats/min, p less than 0.001). The present findings show that beta blockade has negative effects on exercise capacity in patients with complete heart block treated with VVI pacemakers. This finding should be considered in the selection of drug treatment in patients with fixed rate pacing and concomitant hypertension and/or ischemic heart disease.
Three-year-old girl with eight month history of convulsive syncope due to complete heart block, prolonged QT interval and paroxysms of ventricular tachycardia is described. An episode of torsade de pointes tachycardia followed by asystole was documented. The symptoms and electrocardiographic abnormalities were controlled by pacemaker therapy. The subset of "congenital heart block" patients with prolonged QT interval is at high risk of sudden death and should be regarded as a previously unrecognized form of Romano-Ward syndrome.
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Ventricular pacing thresholds were measured in barbiturate-anesthetized dogs with complete heart block using an oscilloscope and current probe. All electrode and physiologic variables were carefully controlled in order to compare the effects of stimulus duration and site of ventricular threshold energy requirements. Left ventricular intramyocardial stimulation, at all stimulus durations under 5 msec., required less current and energy, and at all stimulus durations under 2 msec. less voltage, than either right ventricular endocardial or right ventricular intramyocardial stimulation. Chronaxy and polarization losses were lowest and impedance highest with left ventricular intramyocardial stimulation. The two right ventricular sites were almost equivalent electrically. Earlier studies which reported lower thresholds with endocardial stimulation than with intramyocardial stimulation were biased in favor of the endocardial site by lack of control of electrode variables including: material, configuration, cross-sectional area, and epicardial versus intramyocardial location.
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Quadricuspid aortic valves are rarely encountered by the cardiac surgeon during aortic valve replacement. The most common location for the supranumerary cusp is between the noncoronary and the right coronary cusp, located over the membranous septum, which can potentially increase the risk of complete heart block after valve replacement. We present three quadricuspid aortic valve replacements, one of which was complicated by complete heart block postoperatively. We suggest a strategy to possibly avoid this complication.
HLA-B27 associated rheumatic syndromes have been found in 13% of more than 200 pacemaker treated Caucasian men. Furthermore, a significantly increased frequency of HLA-B27 was found in pacemaker treated men without HLA-B27 associated rheumatic disorders. Consequently, an HLA-B27 associated disease process seems to be the cause of heart block development in 15 to 20% of Caucasian pacemaker treated men. The purpose of our study was to find out if the HLA-B27 associated disease process was equally common in pacemaker treated women. Eighty-five pacemaker treated women with second and third degree heart block were HLA typed for B27, and HLA-B27 positive individuals were further examined for the presence of associated rheumatic disorders. HLA-B27 was present in 7 women, 8.2%, similar to the frequency in the general population, and none of them had an associated rheumatic disease. Thus, there is a significant sex linked difference in the susceptibility to HLA-B27 associated heart block.
We describe the occurrence of complete heart block in a patient with Sjögren's syndrome. The patient's serum contained antibodies to both the 60-kd and 52-kd Ro proteins. This case indicates that although the adult atrioventricular node may be relatively resistant to the development of anti-Ro-associated heart block, it can nevertheless be affected.
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Two siblings were born with congenital heart block, and one suffered from severe hydrops fetalis, although maintaining a higher heart rate than the other. The association of hydrops fetalis with disorders of cardiac rhythm is unlikely to be simply a manifestation of congestive cardiac failure in the fetus.
This study describes the natural history and evolution of 67 patients with congenital auriculoventricular heart block admitted in the Instituto Nacional de Cardiología "Ignacio Chávez", Mexico, D.F. from 1944 to 1998. There were 35 (52%) females and 32 (47%) males, with mean follow up period of 93.7 +/- 104 months. Most of the patients were without structural cardiovascular disease (90%). The most frequent symptoms were dyspnea and syncope. Electrocardiograms showed a ventricular heart rate of 42.2 +/- 9 beats/minute. 85.7% of patients had a supra-Hisian complete heart block. In 31% of patients a pacemaker was implanted because syncope. Overall mortality was 4.4% and malignant ventricular arrhythmias were the principal contributors. Risk factors for mortality identified in this study were junctional escape rhythm lower than 50 beats/minute, inappropriate chronotropic response during exercise, R-R interval prolongation at night, enlargement of cardiac chambers, depressed left ventricular ejection fraction and prolonged QT interval. In all of these conditions we recommend permanent pacemaker implantation.
Ethanol septal ablation has emerged as a less invasive alternative to surgical myomectomy for treatment of asymmetric hypertrophic obstructive cardiomyopathy (ASH). The procedure has very low mortality, but high-degree AV conduction block is a frequent complication. Prior studies have documented baseline left bundle branch block and high volume of ethanol injection (greater than 4 mL) as risk factors. Complete heart block is often preceded by postprocedure conduction abnormalities and generally develops within 48 hours after ethanol ablation. We present a unique case of a patient with symmetric hypertensive hypertrophic obstructive cardiomyopathy (SHOCM) who developed phase IV complete heart block >96 hours postprocedure without preceding conduction abnormalities or other classic risk factors.