Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transesophageal, electrophysiologic studies were conducted in 47 patients, with clinical and ECGgraphic diagnosis of paroxysmal reciprocating supraventricular tachycardia. After admission to hospital, the patients were enrolled in the study in accordance with the criterion concerning the exclusion of patients with signs and symptoms of severe heart pump failure (ie, NYHA III and IV class were excluded). The transesophageal study was performed during paroxysmal tachycardia in each patient to measure the V-A interval and to localize the site of reentry. Thereby, the patients could be grouped into 2 subsets, ie those with A-V nodal reentrant tachycardia (no. 30 patients) and those with accessory pathway reentrant tachycardia (no. 17 patients). Moreover, the prevalence in both subsets was evaluated in the following signs and symptoms: palpitations, dyspnoea, chest pain, pulsations in the neck, significant increase in urinary output, hypotension, dizziness, near-syncope, syncope, shock, focal brain injury. From the data analysis, significantly greater prevalence of palpitations in the neck resulted in the subset of patients with reentry confined to the A-V node (no. 20 cases) compared with those suffering from reentry via accessory pathway (no. 4 cases). Moreover the arterial pressure, in A-V nodal reentrant tachycardia, showed the lowest values and the best decreases, together with the finding of a more rapid trend to decline in comparison with the accessory pathway subset. On the other hand, no significant differences could be seen about the remaining symptoms. In an attempt to provide the reliable explanation for the differences found between the 2 subsets of study, concerning both the unpleasant pulsations in the neck and the pressure decrease, we postulated a remarkable role for the length of arrhythmic circle movement. The smaller dimensions of circuit limbs, in A-V nodal reentrant tachycardia, are likely to be the principle cause of the different clinical features of 2 types of reentry. We speculate actually that in susceptible patients the critical event is most likely to be A-V functional dissociation due to early and unphysiologic activation of atria by stimulus rapidly reentrant from the bottom portion of the AV node: the simultaneous occurrence, frequent in A-V node reentry, of both, atrial and ventricular mechanical activation, would result, however, in impairment of atrial haemodynamics due to development of cannon A waves, able either to activate a vasodepressor reflex from the atria or to stimulate instantaneous release of atrial natriuretic factor in the circulation. Further studies, however, are necessary to be performed on large cases-records, to confirm our hypothesis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Differences in the symptomatology of paroxysmal supraventricular tachycardias in relation to the different sites of localization of the arrhythmic reentry circuit. Clinical picture, semiologic and genetic aspects]. 845 Oct 24

Mitral valve prolapse (MVP), is the most frequent valvulopathy, although it is difficult to evaluate its incidence since this pathology is often asymptomatic. However, in some patients a rich variety of symptoms such as chest pain, dyspnea, palpitations, syncope, dizziness, panic attacks and autonomic dysfunctions have been found. The pathogenesis of these symptoms, incompletely understood, appears to be multifactorial, related to altered autonomic function, adrenergic responsiveness and to combinations of these factors. In patients with MVP a variety of neuroendocrine anomalies has been found: high epinephrine and norepinephrine plasma levels, altered rennin-angiotensin-aldosteron (RAA) response to volume depletion and orthostatic stimulation, and high plasma levels of atrial natriuretic factor (ANF) especially in hypovolaemic individuals. The role of ANF could be important in the genesis of MVP syndrome, it could contribute to determine: the imbalance between the sympathetic and parasympathetic system, the altered RAA response to orthostatic stimulus, the volemic and venous flow reductions (with a direct action, other than diuretic and natriuretic action). Factors that can determine ANF secretion abnormality in MVP could be: 1) Mitral regurgitation; 2) increased heart rate and the high incidence, in MVP syndrome, of arrhythmias; 3) central nervous system neuroendocrine imbalance; 4) increased catecholamines secretion.
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PMID:Atrial natriuretic factor and mitral valve prolapse syndrome. 1153 51

Although several investigations on mitral valve prolapse syndrome (MVPS) have been performed, clinical symptoms of this syndrome are not yet clarified. Atypical chest pain, palpitations, fatigue, dyspnea and anxiety are the most frequent symptoms associated with this syndrome. However, dizziness and syncope may be serious symptoms in MVPS. Dizziness and syncope are related to cardiac arrhythmias and are proposed to distinguish types, frequency of arrhythmias and relation to the symptoms. Orthostatic hypotension and tachycardia rarely occur in MVPS. The physiopathological mechanisms of these symptoms are not known clearly, but multifactorial causes are thought to be responsible including autonomic dysfunction, hyperadrenergic state, abnormalities in regulation of baroreceptors, parasympathetic derangements, decrease of intravascular volume, abnormal renin-aldosterone response to depletion of intravascular volume and abnormal release of atrial natriuretic factor.
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PMID:[Mitral valve prolapse syndrome: orthostatic hypotension and physiopathology of its clinical symptomathologies]. 1262 13