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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Noninvasive myocardial imaging with potassium-43 and rubidium-81 has been used successfully to identify areas of infarction and exercise-induced ischemia as regions of decreased radioactivity. The image defects observed are believed to be due to a decreased radionuclide uptake in regions of myocardial scar or to heterogeneous myocardial accumulation of tracer as a result of regional ischemia. Of 27 patients with left bundle branch block studied with noninvasive imaging at rest and during exercise, 25 manifested at rest reduced radioactivity in the region of the interventricular septum. This pattern is similar to that seen in patients with anteroseptal myocardial infarction. Sixteen of the 27 patients underwent diagnostic coronary arteriography and left ventriculography. Only five of these patients had evidence of either previous infarction or significant obstructive coronary artery disease as assessed with clinical or angiographic criteria, or both. Although the image defect was routinely demonstrated at rest in patients with left bundle branch block, this defect was generally normalized or less distinct with exercise in patients with no anatomic heart disease. In contrast, a larger, more distinct or new image defect with exercise correctly identified the presence of significant obstructive coronary artery disease in patients with left bundle branch block. In the clinical application of noninvasive myocardial imaging, these image defects observed at rest can lead to the false pasitive radionuclide interpretation of anteroseptal myocardial infarction.
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PMID:Noninvasive myocardial imaging with potassium-43 and rubidium-81 in patients with left bundle branch block. 97 Mar 29

Sixteen of 994 patients with arteriosclerotic heart disease and dominant right coronary arteries had isolated left circumflex obstruction. Of these, 6 patients had significant (75%) narrowing in the main circumflex, 10 in 1 or the marginal branches and 1 in the atrioventricular groove branch. Angina was mild in 5, moderate to severe in 8, and unstable in 1. Four patients had prior myocardial infarction (MI), and 1 had a recent MI complicated by posterior papillary muscle rupture. The EKG was normal in 5, showed an MI in 2, LBBB in 1, RBBB in 2, ST-T wave changes in 3, LVH in 2, and atrial fibrillation in 2. Left ventricular angiography performed in the right anterior oblique projection revealed normal contraction in 9 patients, apical hypokinesis in 4, posterobasal hypokinesis in 1, and diffuse hypokinesis in 2. The left ventribular end diastolic pressure was normal in 11 patients and elevated in 5. The cardiac index was normal in 12 patients and reduced in 2. Isolated, nondominant, left circumflex coronary disease is an uncommon entity in symptomatic patients. However, when present, it may produce significant clinical and hemodynamic impairment.
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PMID:The clinical and angiographic spectrum of isolated, nondominant, left circumflex coronary disease. 99 Dec 64

Systolic time intervals and heart sounds were studied in twenty patients with left bundle branch block. A definite cause for the organic heart disease was not ascertained. Abnormal duration of the electromechanical systole (Q-A2), due to a prolongation both of the preejection period (PEP) and of the Q-M1 intervals, was found to exist in all. Prolongation of Q-M1 was due to lengthening either of the electromechanical interval (EMI) or of the pre-isovolumetric contraction time (PICT). Isovolumetric contraction time (ICT) was prolonged in thirteen patients only. There was a good correlation between LVET/ICT ratio and the duration of ICT intervals. Six patients showed a first heart sound of normal intensity and duration. There was no correlation between the duration of the systolic time intervals and the characteristics of the first and second heart sounds.
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PMID:Systolic time intervals and heart sounds in left bundle branch block. 107 20

Nine atrial pacing (SP) runs and 8 ventricular pacing (VP) runs were carried out in patients without heart disease, and 10 AP runs in patients with coronary artery disease (CAD). For evaluation of myocardial contractility, the time derivative of left ventricular pressure (dpdt) was used. Comparing rest and AP at 155/min, AP in normal patients revealed a significant increase in dP/dtmax and a significant decrease in left ventricular end-diastolic pressure (LVEDP). This represents frequency potentiation. When comparing rest and VP values at 155/min in normal patients, no changes in dP/dtmax and LVEDP were seen. AP in patients with CAD demonstrated no change in dP/dtmax, but a decrease in LVEDP when compared to the rest values. dP/dtmin and left ventricular systolic pressure did not change in the 3 groups. VP, and even AP, in 2 additional patients with isolated left bundle branch block (LBBB) AND WITHOUt associated heart disease, revealed the same constellation of parameters as VP in normal patients. Our results show a lack of frequency potentiation in normal patients during VP and in patients with isolated LBBB during both AP and VP. It is concluded that the lack of frequency potentiation during AP in CAD is produced primarily by mechanical asynchrony of contraction, angiographically demonstrated as akinesia and dyskinesia. The lack of frequency potentiation in normal patients during VP and in patients with isolated LBBB due to asynchrony of activation resulting in asynchrony of contraction.
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PMID:Mechanical and electrical causes for lack of frequency potentiation in normal patients, in coronary artery disease and in left bundle branch block. 108 Jan 9

The experience with bundle branch block at the USAF School of Aerospace Medicine was reviewed. The clinical and follow-up status was evaluated in 394 subjects with right bundle branch block (RBBB) and 125 subjects with left bundle branch block (LBBB). The majority of subjects were asymptomatic at the time of bundle branch block diagnosis. The subjects were divided into subfroups based on electrocardiographic (EEG) findings to determine if any one subfroup was at higher risk for initial or follow-up morbidity of cardiobascular disease or follow-up mortality. At initial diagnosis and clinical evaluation, 94% of RBBB and 89% of LBBB subjects had no evidence of cardiobascular disease. In the RBBB group, 3 and 2% had cornary heart disease and hypertension, respectively; in LBBB subjects, 9 and 7% had cornary heart disease and hypertension, respectively. No one ECG subfroup in either the RBBB or LBBB group had a higher incidence of cardiobascular disease. Complete follow-up information was available in 94% of the RBBB subgroup subjects and 91% of the LBBB group. In the follow-up period, new cases of coronary heart disease and hypertension occurred in 6% of the RBBB group and 5 and 8%, respectively, in the LBBB group. Fourteen (4%) RBBB and nine (8%) LBBB subjects died during the follow-up period. No differences for follow-up groups. Progressive electrical dysfunction in the form of complete heart block occurred in one subject each absence, and degree of associated cardiobascular disease. Furthermore, within the age limits of the present aeromedical implications of bundle block are discussed.
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PMID:A clinical and follow-up study of right and left bundle branch block. 113 86

We reviewed 144 consecutive patients with symptomatic high grade atrioventricular block. Cases due to congenital heart disease, acute myocardial infarction, cardiac surgery or digitalis toxicity were excluded. Of the remaining, we chose 71 patients in whom atrioventricular conduction was observed either intermittently during complete heart block (CHB) or in electrocardiograms taken within two years prior to documentation of CHB. The mean age was 69 years, with the peak incidence in the seventh decade in 43 men and eight decade in 28 women. Bundle branch block (BBB) was present in 76% of patients as follows: 47% had right BBB (20% with normal QRS axis, 20% with left axis deviation and 7% with right axis deviation), 17% had left BBB (11% with normal QRS axis and 6% with left axis deviation) and 12% had either alternating BBB, right BBB with alternating axis deviation or atypical BBB. "Trifascicular block" patterns accounted for 21% of the total group of CHB. We also studied the prevalence of various patterns of BBB in a group of 2000 random hospital patients of comparable age and sex exclusive of those with acute myocardial infarction and heart surgery. The risk of CHB for the various patterns of BBB was calculated relative to normal intraventricular conduction. All patterns of BBB carried a considerably increased relative risk of CHB, (P smaller than .01). The relative risk was highest for RBBB with left axis deviation and lowest for LBBB with normal or left axis deviation. In the men, 74% had QRS patterns of "bifascicular" or "trifascicular" block during atrioventricular conduction. By contrast, 71% women had atrioventricular beats showing either no BBB or right BBB with normal QRS axis. QRS pattern during CHB was unchanged from that during atrioventricular conduction in 52% if cases (rabge 38%-76% with different QRS patterns) suggesting idiojunctional pacemaker. CHB in these cases was thought to be due probably to coexistent disease in the AV node or His bundle. Although the concept of uni-, bi- and trifascicular block patterns has been useful in identifying patients at greater risk of CHB, the predictability of the electrocardiogram has obvious limitations, particularly in women.
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PMID:The relative risk of spontaneous complete atrioventricular block in elderly patients with impaired intra-ventricular conduction. 115 Dec 1

In three patients with congenital heart disease the site of atrioventricular (A-V) block was localized within the His bundle with the aid of His bundle electrograms. In one patient with first degree A-V block and normal QRS configuration, electrophysiologic studies revealed "split" His potentials. The other two patients had complete A-V block, and their His bundle electrograms revealed His spikes both proximal and distal to the site of block. One of the two patients, who had a pattern of left bundle branch block in the electrocardiogram, had surgically induced complete A-V block after repair of an ostium primum atrial septal defect. The other patient with congenital A-V block had a narrow QRS complex and, in addition to complete block within the His bundle, prolonged A-V nodal conduction time but no associated cardiac anomaly. Both patients with complete heart block required pacemaker insertion. The natural history of intra-H-is bundle block is not known, and it is difficult to recommend appropriate therapy. More electrophysiologic studies are needed in patients with A-V block to determine the prognostic significance of such block or conduction delay in the His bundle.
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PMID:Congenital and surgical atrioventricular block within the His bundle. 119 47

This phonocardiographic-echocardiographic study was based on measurement of the interval between the aortic component of the second sound (IIA) and the peak of the E wave of the mitral echogram. The study was performed in 20 cases of left bundle branch block (LBBB), 10 cases of right bundle branch block (RBBB), 10 cases of old myocardial infarct (MI), and 10 cases of systemic hypertension (HY). All patients were above 60 years of age, and their data were compared with those of old persons without evidence of heart disease serving as controls. The IIA-E interval was found markedly prolonged in LBBB, less prolonged in MI and RBBB, and was shortened in HY. A dynamic analysis revealed that this interval results from the isovolumic relaxation period (IRP) of the left ventricle plus the "opening time" of the mitral valve. The changes observed were explained as resulting from a modification of the IRP that should be correlated with a similar modification of the isovolumic contraction time. Myocardial fibrosis would cause prolongation of IRP through structural lesions while hypertension would cause abbreviation of IRP through hormonal effects modifying both contraction and relaxation.
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PMID:Ventricular relaxation and mitral opening time in various ventricular conditions of old age. 121 36

Electrophysiological studies (His bundle recordings and atrial stimulation) were performed in nine patients who manifested periods of both right and left bundle branch block (RBBB and LBBB). In seven of the patients, alternating bundle branch block appeared to reflect intermittent or chronic bundle branch block superimposed on incomplete (but electrocardiographically complete) block of the contralateral bundle branch. In three of these seven, shift from one bundle branch block pattern to the other was associated with reproducible change in H-V (mean change 30 msec), and could be induced by alteration of cardiac rate with carotid massage, coupled atrial stimulation, and rapid atrial pacing. In one of the seven, RBBB with a P-R of 0.20 seconds preceded chronic LBBB with a P-R of 0.24 seconds, implying that RBBB had been incomplete. In three of the seven, although a definite mechanism of alternation could not be demonstrated, transient contralateral bundle branch block occurred superimposed on chronic ipsilateral bundle branch block, implying that the ipsilateral block was incomplete. Two patients manifested periods of narrow QRS, LBBB, RBBB, and paroxysmal A-V block. Based upon pathological data (one case), this pattern appeared to reflect a lesion involving the distal His bundle and proximal bundle branches. In the total group of patients, clinical course was primarily determined by the severity of heart disease and not by occurrence of A-V block. The conduction defect in the majority of patients was surprisingly benign.
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PMID:Electrophysiological and clinical observations in patients with alternating bundle branch block. 124 77

Eleven patients with an exercise dependent complete left bundle branch block (CLBBB) were followed-up over a period of 2-13 years (mean 6.5 +/- 3.8). Their ages ranged from 19 to 62 years (mean 48). Four patients complained of chest pain on effort and one of palpitations. All patients underwent a clinical examination, 12 lead ECG, routine blood tests, chest X-ray, a multistage exercise test, echo Doppler, radionuclide ventriculography with TC99 and 48-h Holter monitoring. Ten were submitted to a coronary angiography with left ventriculography. The ECG at rest displayed a normal ECG in seven patients and an incomplete left bundle branch block (ILBBB) in four patients. The onset heart rate (HR) of CLBBB ranged from 95-146 beats.min-1 (mean 123) and the offset HR75-135 (mean 102 beats.min-1). Coronary angiography showed three-vessel disease in two patients and an obstruction of the left anterior descending coronary artery (LAD) in the third. In the other seven patients all the investigations (including coronary angiography) were normal. During the follow-up period the HR at onset of CLBBB decreased from 145 beats.min-1 to 100 beats.min-1 in four patients but no coronary artery disease (CAD) could be proven at coronary angiography. In our series chest pain did not always signify the presence of CAD. We conclude, that in patients with exercise-dependent CLBBB the prognosis is good if no underlying heart disease can be detected. It appears from our limited experience that an exercise-dependent CLBBB at heart rate below 125 beats.min-1 does not by itself constitute a sign of CAD.
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PMID:Exercise dependent complete left bundle branch block. 146 33


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