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At least 667 records · Page 37Linked to original sources
PubMed1971

The peripheral vascular response to severe exercise in untethered dogs before and after complete heart block.

The peripheral vascular response to severe exercise was studied in 11 healthy conscious dogs instrumented with Doppler ultrasonic flow probes on the mesenteric, renal, and iliac arteries, and miniature pressure gauges in the aorta. The response to severe exercise was restudied in six of these dogs after recovery from a second operation producing complete heart block by the injection of formalin into the atrioventricular (AV) node. Three of these dogs also exercised while their ventricles were paced at rates of 100/min and 200/min. The untethered normal dogs ran at speeds of 15-25 miles/hr behind a mobile recording unit for a distance averaging 1.5 miles, while continuous measurements of arterial blood pressure and blood flow were telemetered and recorded on magnetic tape. Severe exercise in normal dogs increased heart rate from 84 to 259/min, arterial pressure from 89 to 140 mm Hg, flow resistance in the mesenteric and renal beds by 59 and 52% respectively, and iliac blood flow 479% above control, while mesenteric and renal blood flows remained constant and iliac resistance decreased by 73%. In dogs with complete AV block, severe exercise at speeds of 10-18 miles/hr increased heart rate from 47 to 78/min, mean arterial pressure from 81 to 89 mm Hg, iliac flow 224%, resistance in the renal bed by 273%, and mesenteric bed by 222% while it decreased blood flow in mesenteric and renal beds by 61 and 65% respectively, and iliac resistance by 62%. A similar response occurred during exercise with pacing at 100/min, but when paced at 200/min a more normal exercise response reappeared. Thus, in normal dogs the peripheral vascular response to severe exercise involved increases in heart rate, arterial pressure and visceral resistance but visceral blood flow did not decrease. In dogs with heart block, where the ability to increase heart rate is severely compromised, compensatory reduction of mesenteric and renal blood flows occurred.

Abdomen↗
PubMed2006

Doppler echocardiographic and electrocardiographic atrioventricular time intervals in newborn infants: evaluation of techniques for surveillance of fetuses at risk for congenital heart block.

OBJECTIVE: To evaluate one novel and two previously reported Doppler flow velocimetric techniques to estimate atrioventricular (AV) time intervals, suggested to be useful for early identification of fetuses at risk for congenital heart block. METHODS: In 22 newborn infants, Doppler tracings were obtained from the mitral valve/aortic outflow and the superior vena cava/ascending aorta, as an ECG was recorded simultaneously. AV time intervals were measured using the onsets of the mitral A-wave/aortic outflow (MV-Ao), superior vena cava a-wave/aortic flow (SVC-Ao), and mitral A-wave/mitral valve closure (MV) as indirect markers of electrical atrial/ventricular activation. RESULTS: Close positive linear relationships to the electrocardiographic PR interval were demonstrated for the MV-Ao (r = 0.82, S(y/x) = 7.4 ms), SVC-Ao (r = 0.85, S(y/x) = 6.8 ms), and MV (r = 0.92, S(y/x) = 3.8 ms) approaches. Both techniques using the aortic flow to indicate ventricular activation overestimated the PR interval: the MV-Ao by + 32 +/- 7.7 ms (mean +/- SD) and the SVC-Ao approach by + 22 +/- 7.0 ms. The new MV approach using mitral closure for the same purpose did not overestimate the PR interval, but there was a trend towards underestimation of the PR intervals as time intervals increased. CONCLUSIONS: When systematic differences between echocardiographic and electrocardiographic AV time intervals are compensated for, all three techniques are useful to get indirect estimates of the PR interval. As MV recordings only need insonation of a single valve, and are thus easier to obtain, this technique may be of value as a first screening method to identify fetuses in need for further surveillance. In cases with AV time prolongation the SVC-Ao method seems superior.

Analysis of Variance↗
PubMed1963

Surgical heart block.

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Cardiac Surgical Procedures↗
PubMedDate not supplied

[Heart blocks in gallstone].

UNLABELLED: In this study, I analysed the AV blocks and BB blocks which I found in gallstone. OBJECTIVES: The objectives were to find if the heart blocks are in relationship with gallstone or not. METHODS: From 1122 patients with gallstone--13 had the AV blocks and 95 had BB blocks. All of these were examined: physical examinations, abdominal echography and Ecg. RESULTS: This study, 1.15% from the patients had AV blocks and 6.68% had BB blocks, especially RBB blocks, LBB blocks and AV1 block. CONCLUSIONS: I approximate that these diseases of the heart can coexist with gallstone.

Adolescent↗
PubMed2002

Congenital heart block in neonatal lupus: the pediatric cardiologist's perspective.

CLINICAL PRESENTATION: Congenital heart block (CHB) in the absence of major structural abnormalities is associated with maternal antibodies to Ro (SS-A) and La (SS-B). CHB is most commonly diagnosed between 18 and 24 wk of gestation, and may be first, second or third degree (complete). Mortality approaches approximately 20%, and most surviving children require pacemakers. Affected infants may develop cardiomyopathy. Abnormalities in the skin, liver and blood of neonates are also associated with anti-Ro/La antibodies, and are usually self-limiting; these manifestations and CHB are collectively referred to as neonatal lupus syndromes (NLS). INVESTIGATION OF PATHOGENESIS: Recent studies demonstrate that Ro/La ribonucleoproteins appear on the surface of apoptotic fetal cardiocytes and are recognized by their cognate antibodies, promoting an inflammatory response. Mice immunized with Ro/La proteins have offspring with conduction abnormalities. In vitro, human serum and IgG with anti-Ro/La antibodies affect the conducting properties of isolated animal heart tissue. DIAGNOSTIC PROBLEMS: If fetal bradycardia is identified, a 2-dimensional and M-mode fetal echocardiographic and Doppler ultrasound should be obtained to determine whether there is an atrial arrhythmia or atrioventricular (AV) block, and to what degree, and whether there are major structural abnormalities of the heart. The mother's serum should be tested by ELISA for anti-Ro and/or anti-La antibodies. THERAPEUTIC OPTIONS: To date, only anecdotal and retrospective evidence guides in utero therapy of CHB. A prospective trial is currently underway to evaluate the efficacy of maternal oral dexamethasone in treating newly identified first, second or third degree block. Established third-degree block appears to be irreversible. Dexamethasone and sympathomimetics may be of some benefit in treating hydrops fetalis. In pregnant women with anti-Ro/La antibodies, prophylactic therapy is not indicated but serial echocardiographic analysis is strongly recommended, with emphasis on the mechanical PR interval to identify a reversible block. CONCLUSION: CHB occurs in approximately 1-5% of pregnancies in mothers with anti-Ro/La antibodies, independent of the mother's disease status, and in approximately 15-20% of pregnancies following the birth of a child with NLS. Treatment of CHB identified in utero is not established but guidelines are provided. Serial echocardiographic monitoring of high-risk pregnancies, using the mechanical PR interval to identify first degree block, may afford the earliest opportunities for therapeutic intervention.

Antibodies, Antinuclear↗
PubMed2006

52-kDa Ro/SSA epitopes preferentially recognized by antibodies from mothers of children with neonatal lupus and congenital heart block.

Neonatal lupus erythematosus is a rare disorder caused by the transplacental passage of maternal autoantibodies. The 52-kDa Ro/SSA antigen (Ro52) ribonucleoprotein represents an antigenic target strongly associated with the autoimmune response in mothers whose children have neonatal lupus and cardiac conduction disturbances, mainly congenital heart block. The objective of this study was to identify putative Ro52/60-kDa Ro/SSA antigen (Ro60) epitopes associated with neonatal lupus and congenital heart block. The reactivity of IgG antibodies present in the sera from mothers with systemic lupus erythematosus and Sjögren's syndrome and in the sera from asymptomatic mothers (a longitudinal study of 192 samples from 66 subjects) was investigated by ELISA using Ro52, Ro60 and 48-kDa La/SSB antigen proteins, as well as 45 synthetic peptides, 13-24 residues long, of Ro52/Ro60 proteins. One to 19 samples collected before, during and after pregnancy were available for each mother. Forty-three disease controls selected randomly and normal sera were tested in parallel. Although no differences were found between Sjögren's syndrome and asymptomatic mothers of group I, who had at least one infant with neonatal lupus, and of group II, who had healthy babies only, significant differences were observed between lupus mothers from both groups. In the former group of lupus mothers, a significantly higher frequency of antibodies to Ro52 peptides 107-122 and 277-292 was observed. Between 18 and 30 weeks of gestation, the period of risk, there was clearly an elevated level of antibodies reacting with Ro52 peptides 1-13, 277-292 and 365-382. Antibodies to Ro52 peptide 365-382 have been shown previously to cross-react with residues 165-185 of the heart 5-HT4 serotoninergic receptor, and might be pathologically important. The level of these Ro52 antibody subsets decreased at the end of pregnancy and after delivery. IgG antibodies to Ro52 peptides 1-13, 107-122, 277-292 and 365-382 may therefore represent important biomarkers to predict a complication in pregnant lupus women with Ro52 antibodies.

Adult↗
PubMed1987

Use of ambulatory electrocardiographic monitoring to identify high-risk patients with congenital complete heart block.

To define the long-term natural history of congenital complete heart block, we followed 27 patients prospectively by means of frequent ambulatory electrocardiographic (ECG) recordings for a mean (+/- SD) of 8 +/- 3 years. During that time, 8 of the 13 patients with a mean daytime heart rate below 50 bpm (Group A) had cardiac complications such as sudden death, syncope, presyncope, or excessive fatigue. Six of the eight patients had additional ECG findings that suggested an instability of the junctional escape mechanism. These findings included nocturnal junctional exit block (three patients), little or no change in the junctional rate with physical activity (three patients), and associated tachyarrhythmias (three patients). None of the 14 patients with a mean daytime heart rate of 50 bpm or more (Group B) had an adverse clinical outcome, and 5 of the 13 patients in Group A also remained well. Among the five patients in stable condition in Group A, three had no evidence of an unstable junctional mechanism. We conclude that patients with a mean daytime junctional rate below 50 bpm and other evidence of an unstable junctional escape mechanism should probably undergo prophylactic pacemaker implantation. Since junctional exit block and tachyarrhythmias sometimes appear first during follow-up, the method of risk stratification employed in this study depends on serial ambulatory ECG recordings.

Adolescent↗
PubMed1982

Heart block and idiopathic pulmonary hemosiderosis.

A young woman with idiopathic pulmonary hemosiderosis (IPH) and advanced heart block below the atrioventricular node requiring pacemaker therapy is discussed. Thirteen years after the onset of IPH she is free of pulmonary symptoms despite having never received steroid or antimetabolite therapy.

Adolescent↗
PubMed2006

Newborn infant with maternal anti-SSA antibody-induced complete heart block accompanying cardiomyopathy.

Newborn case of maternal anti-SSA antibody-induced congenital complete heart block (CCHB) accompanying cardiomyopathy is presented. Unexpectedly, she died of ventricular tachycardia, not bradycardia, 6 days after birth. Autopsy revealed left ventricular cardiomyopathy with endocardial fibroelastosis. Thus, when evaluating fetal cardiac performance in cases of maternal anti-SSA antibody-induced CCHB, it is necessary to pay attention to myocardial attributes such as endocardial hyperplasia.

Antibodies, Antinuclear↗