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

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

Eighteen of 388 patients with chronic bundle branch block, studied electrophysiologically and followed prospectively, had H-V intervals of 80 msec or greater. Five patients were functional class I, five class II, seven class III, and one class IV. Follow-up ranged from 103 to 1919 days (mean 711 +/- 118). Three patients needed permanent pacing for the following indications: sino-atrial block, sinus bradycardia post-cardiac surgery, and 2 degrees block distal to the His bundle. Six patients died, three suddenly, and three nonsudden. The five initially asymptomatic patients are alive and without pacemakers (mean follow-up 732 +/- 139 days). Although marked H-V prolongation was associated with high morbidity and mortality in this small series, this was only in patients with symptomatic heart disease. Asymptomatic patients (five patients) had a benign clinical course. Prophylactic pacing would probably not modify clinical course in the former group, and is probably not indicated in the latter group. Longer follow-up will be needed for definitive prognostication.
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PMID:Prospective observations in patients with chronic bundle branch block and marked H-V prolongation. 125 80

Concealed (C) His bundle ectopic systoles (H') have been shown in man to give rise to first and second degree atrioventricular (A-V) block and to simulate nonconducted atrial premature beats (P'). This report outlines a hitherto undescribed electrophysiologic consequence of H' in a 69-year-old man with arteriosclerotic heart disease and a Wenckebach type second degree A-V block in the His-Purkinje system. During a His bundle study, H' were shown to conduct either to the atria and ventricles with varying relationships to P' and QRS, or to conduct only to the atria, simulating nonconducted P' or atrial fusion beats. Both types of H' could initiate a re-entrant arrhythmia during retrograde conduction. Of particular interest are late coupled H' that failed to conduct to the ventricles and also failed to activate the atria because of prior capture by the sinus impulse (CH'). These CH' could also initiate re-entry by conducting retrogradely to engage the subatrial re-entry circuit. Evidence is presented to suggest re-entry occurs by way of a retrograde concealed accessory pathway and antegrade conduction in the atrioventricular node.
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PMID:Re-entry due to manifest and concealed. His bundle ectopic systoles. Report of a case. 126 Sep 97

McLeod syndrome was originally described on the basis of a specific blood group phenotype with weak expression of Kell antigens. This erythrocyte abnormality also causes acanthocytosis. The haematological findings are associated with abnormalities in other organ systems, including neuromuscular manifestations. A 51-year-old patient was followed up for 11 years. He presented with persistent muscle creatine kinase elevation and progressive heart disease and later developed a slowly progressive neuropathy and choreic movements. His younger brother presented with grand mal seizures, involuntary movements and high muscle creatine kinase when aged 43 years. Clinical myopathy was absent in both, yet muscle biopsy showed mild myopathic changes. The presence of a motor axonopathy was supported by electrophysiological findings. One brother also showed sensory axonopathy. The movement disorder suggested accompanying basal ganglia dysfunction. Earlier reports of McLeod syndrome are reviewed with respect to neuromuscular involvement. Absence of the Kx membrane protein seems to be the cause of this multi-system disorder.
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PMID:McLeod syndrome: a distinct form of neuroacanthocytosis. Report of two cases and literature review with emphasis on neuromuscular manifestations. 151 5

Seven out of 829 pediatric cardiac patients (0.84%) were found to have sinus node dysfunction (SND) over the past seven years. Of the seven patients, three had structurally normal hearts. One of these three patients had long QT syndrome. In four patients, structural heart disease was noted. In three of these four patients the sinus node dysfunction was attributed to cardiac surgery. The age of onset of SND ranged from four months to eight years. Presenting symptoms and signs included syncope, near-syncope, seizure and congestive heart failure. Two patients were asymptomatic. Five patients had episodic sinus pause. Sinus or junctional bradycardia was noted in four patients. Three had tachy-bradycardia. High grade atrioventricular block was noted in one patient. Treadmill exercise test revealed a nonsustained ventricular tachycardia in two patients. All seven patients were found to have prolonged maximal corrected sinus node recovery time. Prolonged intra-atrial conduction time was found in three, prolonged AV nodal conduction time in one, and prolonged His-Purkinje conduction time in one patient during the electrophysiologic study. All seven patients showed abnormal results in intrinsic heart rate study. Anti-arrhythmic drugs were prescribed. During the follow-up study, no patient died, but two patients received a pacemaker implantation. Because of the extent of their conduction system diseases, it is recommended that patients with SND should be thoroughly investigated.
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PMID:Sinus node dysfunction in children. 151 8

Infective endocarditis is uncommon in young children, especially in the absence of structural heart disease. We report the case of a 2-year-old boy who presented with acute rupture of the mitral valve chordae 6 weeks after an episode of Fusobacterium necrophorum septicemia. His heart had been structurally normal before. Mitral valve replacement was successfully performed. This is the first recorded case of endocarditis in a child caused by necrobacillosis.
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PMID:Endocarditis with acute mitral regurgitation caused by Fusobacterium necrophorum. 151 43

Twenty-one patients were successfully resuscitated from cardiac arrest. Electrocardiograms (ECG) during cardiac arrest were recorded in 14 patients with ventricular fibrillation in 7, ventricular tachycardia in 4, cardiac standstill in three, Torsade de Points in one and atrial fibrillation with rapid ventricular response in 1. Thirteen patients (group I) had structural heart disease or primary ECG abnormality and 8 patients (group II) had no apparent heart disease. Electrophysiologic study (EPS) was performed in 12 patients of group I and 5 of group II. In group I, ventricular tachycardia was induced in 7, and His-ventricular conduction disturbance was demonstrated in 2, and 2 patients with Wolff-Parkinson-White (WPW) syndrome had an effective refractory period of the antegrade accessory pathway less than 250 msec. No patients in group II showed abnormal EPS findings. Spasm provocation test was performed in 8 patients (2 in group I and 6 in group II). Coronary spasm was induced in 5 patients (1 in group I and 4 in group II). Two patients in group II had positive results of upright-tilt testing. During the follow-up period, 2 patients died suddenly in group I and 1 patient whose cause of cardiac arrest was unknown had a recurrence of cardiac arrest. In group II, all patients whose etiology could be demonstrated by serial examinations had good prognosis. In conclusion, EPS is useful in evaluation of the cause of cardiac arrest especially when patients have structural heart disease, and coronary spasm may be involved in patients with cardiac arrest without apparent heart disease.
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PMID:Role of electrophysiologic testing and coronary spasm provocation test in survivors of cardiac arrest. 157 5

It has been previously demonstrated that radiofrequency (RF) energy can be safely applied to successfully eliminate accessory pathways in patients with the Wolff-Parkinson-White syndrome. This technique may also be used to successfully eliminate atrioventricular (AV) nodal reentrant tachycardia by elimination of either the fast or slow AV nodal pathways. However, RF energy has achieved only limited success in eliminating ventricular tachycardia (VT) in patients with structural heart disease, such as coronary artery disease and dilated cardiomyopathy. Direct-current catheter techniques have successfully eliminated VT in patients with and without structural heart disease, but this technique is limited by the risk of barotrauma and proarrhythmia. We used RF catheter ablation techniques to eliminate VT in patients without structural heart disease. Our results from the basis of this report. 16 patients (nine women and seven men; mean age 38; range 18 to 55 years) who did not have any identifiable structural heart disease by echocardiography where included in this study. These patients underwent RF catheter ablation to eliminate VT. Two patients had presented with syncope, nine with presyncope and five with palpitations only. The mean duration of symptoms was 6.7 years (range 0.5 to 20 years). VT was successfully eliminated by RF catheter techniques in 15 of the 16 patients (a 94% success rate). Importantly, successful ablation sites included regions other than the right ventricular outflow tract. Areas of VT origin therefore included the high right ventricular outflow tract (twelve patients), right ventricular septum near the tricuspid valve (three patients), and the left ventricular septum (one patient). The only ablation failure was in a patient whose VT arose from a region near the His bundle. Successful ablation occurred in patients in whom an accurate pace map could be obtained and early local endocardial activation was obtainable. Further, firm catheter contact with endocardium was required for successful elimination of VT. RF ablation did not cause any identifiable arrhythmia and produced a minimal cardiac enzyme rise. It also resulted in no detectable change in cardiac function by Doppler echocardiography. Based on these findings, we conclude that RF catheter ablation of VT in patients without structural heart disease was highly effective and safe. It may therefore be considered as early therapy in these patients.
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PMID:Catheter ablation of ventricular tachycardia using radiofrequency techniques in patients without structural heart disease. 163 37

During the acute phase of Lyme disease, a 56-year-old man without previous heart disease developed complete heart block with alternating left and right bundle branch block pattern QRS complexes. Electrophysiological study performed in the acute phase revealed marked HV prolongation, although the level of heart block was at the atrioventricular node. The heart block was mildly symptomatic and resolved (as did the bundle branch block) with antibiotic therapy. Lyme disease may cause reversible His-Purkinje disease.
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PMID:Acute reversible diffuse conduction system disease due to Lyme disease. 170 88

The diagnostic approach to cardiac arrhythmias should be logical and starts with the clinical history, which provides two types of information: (a) the presence of symptoms, and (b) the clinical context, including the presence of an underlying heart disease. Clinical history and examination are helpful in the choice of pertinent invasive or noninvasive tests. The tolerance of the arrhythmia is not helpful in determining the type of arrhythmia because ventricular tachycardia, for example, may be well tolerated or even asymptomatic. The electrocardiogram (ECG) in sinus rhythm may be suggestive of the origin or etiology of arrhythmia as the presence, for example, of the Wolff-Parkinson-White pattern. An essential step in the diagnostic approach to arrhythmia is the ECG documentation. Ambulatory Holter monitoring, radiotelemetry, intermittent recorders, exercise testing, and electrophysiological testing will help in this endeavor. The latter is particularly useful in paroxysmal circus movement tachycardias. Once the tachycardia is recorded, a number of clues, including the regularity of the RR interval and the width of the QRS complex, may facilitate the diagnosis. In tachycardias with wide QRS complexes, preexcitation has to be excluded. The first step is then to look for atrioventricular dissociation, which is diagnostic of ventricular tachycardia. Other diagnostic clues (QRS duration, axis deviation, QRS morphology) may be useful. In case of difficulty because of preexisting bundle branch block or aberrancy, esophageal, right atrial, or His bundle recordings are indicated. If the tachycardia is not well tolerated, prompt termination with electrical DC shock should be performed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diagnostic approach to cardiac arrhythmias. 172 14


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