Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The electrophysiologic effects of hydralazine were evaluated in nine hypertensive patients with sinoatrial dysfunction. Intravenous hydralazine, 0.15 mg/kg, caused no significant reduction in arterial blood pressure. Yet this dose of hydralazine increased heart rate from 61.9 +/- 4.1 beats/min (mean +/- standard error of the mean) to 68.6 +/- 4.9 (P less than 0.001). Sinus nodal recovery time upon termination of atrial pacing shortened from 3,207 +/- 1,098 to 2,064 +/- 573 msec (P less than 0.05) and second escape cycles shortened as well (P less than 0.025). Acceleration of heart rate and abbreviation of recovery time did not closely correlate with change in blood pressure (r = 0.41 and 0.18, respectively). Junctional escape beats became more frequent and junctional escape time shortened from 2,525 +/- 692 to 1,705 +/- 382 msec (P less than 0.05). Sinoatrial conduction time tended to shorten, but a significant change was not observed. Atrial tachyarrhythmias did not occur and atrial refractoriness was unchanged. Thus, a minimal blood pressure response to hydralazine was associated with enhanced automaticity. Hydralazine merits clinical trial for treatment of sick sinus syndrome with concomitant hypertension.
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PMID:Electrophysiologic effects of hydralazine on sinoatrial function in patients with sick sinus node syndrome. 64 82

Measurement of the sinus node recovery time has been proposed as a diagnostic tool for recognition of the sick sinus syndrome. The latter is most frequently encountered in elderly patients with hypertension, coronary heart disease, and atherosclerosis. In order to provide normal values for the sinus node recovery time in this particular population group, atrial pacing studies were carried out in 30 subjects over 50 years of age, all with peripheral vascular disease and some with angina pectoris (10), residua of infarction (6), or hypertension (7). On stimulation, 7 patients maintained a I:I atrioventricular conduction up to the rate of 180/min. Second degree atrioventricular block developed in all other cases. On six occasions, Wenckebach's periods appeared at the relatively slow pacing rate of 120/min. The maximum postoverdrive pause ranged from 680 to 1600 ms with an average of 1100 ms plus or minus 190 (10). For each pacing speed, a correlation was found between the duration of the pause and the control intrinsic cardiac rate, longer pauses being associated with longer resting PP intervals. Beyond 120/min, the duration of the pause was seen to shorten progressively as the driving rate was increased. Finally, the behavior of the sinus node pacemaker following interruption of pacing showed individual variations. After pacing at relatively slow rates, a prompt return to near control values was consistently observed, whereas, after fast rates of driving, a phase of secondary depression developed in about one-half of the studied cases.
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PMID:Sinus node recovery time in the elderly. 112 18

Polymyositis-dermatomyositis (PM-DM) is an inflammatory disease of muscle and skin mediated by autoimmune and cellular events. Most typically, muscle weakness is the usual presentation. This review emphasizes that often the systemic components of this disease may mask the usual presentation and actually may be the presenting and only manifestations; more often than not they are the causes of increased morbidity and mortality. In particular, the cardiopulmonary manifestations may dominate the disease course. Cardiac complications include congestive heart failure resulting from a primary cardiomyopathy, disrhythmias and atrioventricular conduction disturbances, sick sinus syndrome, and cor pulmonale either secondary to interstitial lung disease (ILD) or primary pulmonary artery hypertension. Recurrent aspiration pneumonia results from pharyngeal muscle involvement by the myositic process. Several histologic patterns of ILD can emerge with varying outcomes and responses to immunosuppresive therapy. Involvement of the muscles of respiration can lead to hypercapnic respiratory failure, diaphragmatic dysfunction, hypostatic pneumonia, and restrictive lung disease.
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PMID:Pulmonary and cardiac manifestations of polymyositis-dermatomyositis. 157 25

For the evaluation of myocardial perfusion in patients with left bundle branch block (LBBB), we performed exercise stress (Ex)-redistribution (RD) myocardial tomography with thallium-201 (201Tl) in 23 patients with LBBB and without coronary artery disease (CAD). Myocardial images in patients with LBBB were compared with those of 9 patients with CAD who showed Ex induced transient septal defect. Bull'-eye maps (201Tl distribution maps at Ex and RD and 201Tl washout rate [WOR] map) were made from myocardial tomograms. In 23 patients with LBBB, 15 patients (65%) developed myocardial perfusion abnormality. In 10 (67%) of these 15 patients, transient perfusion defect appeared in the entire septum (diffuse type). On the other hand in 5 patients (33%), localized fixed perfusion defect developed at the boundary between septum and anterior wall (focal type). In focal type, every patient had other disease such as hypertension, aortic stenosis or sick sinus syndrome. While in patients with diffuse type, other diseases were observed in 30% (p less than 0.05) and they were limited to hypertension or diabetes mellitus. These facts suggested that mechanisms of perfusion abnormalities might be different between these two groups. We compared the perfusion abnormality between LBBB diffuse type and CAD. The extent of the defects was not different between two groups. Although apex was included within the defect in 89% of CAD population, apical defect was observed in only 20% of diffuse type (p less than 0.05). Minimal 201Tl WOR and 201Tl uptake ratio of septum to lateral wall indicated that exercise induced septal defect was slighter in diffuse type than CAD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Myocardial perfusion in patients with left bundle branch block and without coronary artery disease]. 160 38

This report presents 72 cases with mitral annulus calcification. The diagnosis was made by echocardiogram. There were 21 males and 51 females, aged from 38 to 93 (mean 71). The associated clinical findings in these 72 patients included: hypertension, 28 cases; valvular aortic stenosis, 3 cases; hypertrophic cardiomyopathy, 7 cases; chronic renal failure, 14 cases; congestive heart failure, 29 cases, calcified aortic valve, 27 cases; mitral regurgitation, 46 cases; cerebral infarct, 19 cases; peripheral arterial embolism, 2 cases. Their electrocardiographic findings included: atrial fibrillation, 25 cases; conduction defects, 21 cases; sick sinus syndrome, 3 cases (one case required permanent pacemaker implantation). We conclude that mitral annulus calcification is not a senile change only, and that it also results in some complications such as: mitral regurgitation, cerebral embolism, peripheral arterial embolism, atrial fibrillation and conduction defects. Echocardiography is a useful diagnostic tool in the evaluation of patients with mitral annulus calcification.
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PMID:[Mitral annulus calcification: clinical observation on 72 patients]. 167 8

beta blockers and Ca antagonists are popular therapeutic agents for hypertension and ischemic heart disease. Although these are reported to induce various bradycardiac arrhythmias, clinical studies remain insufficient. The author performed a clinical study of sinus node dysfunction caused by drugs for heart and circulatory diseases. Seventy-seven of the 1,734 patients admitted to the CCU of our hospital during the past 11 years, were the subjects of this study. They showed sinus node dysfunction on electrocardiographs (ECG). Forty-two subjects had drug-induced sinus node dysfunction (DISD) and 35 had sick sinus syndrome (SSS). Rubenstein's classification based on 12-lead ECG was used to diagnose DISD and SSS. All patients underwent chest X-ray examination, ECG, echocardiogram and blood chemistry and were divided into DISD and SSS groups. The DISD group was subdivided into an older group (65 years or more), and a younger group. Ten patients in the DISD group were examined electrophysiologically. SSS II and III types appeared in 22 DISD patients (52.3%) and in 31 SSS patients (88.5%). Bradycardia in the DISD group was milder than in the SSS group, because the DISD group had a higher minimum heart-rate and a shorter maximum R-R interval. However, the DISD group showed significantly lower blood pressure and renal function and a higher grade on the New York Heart Association's (NYHA) classification. Echocardiographic findings following recovery were similar in the two groups. Electrophysiological examination revealed abnormal sinus node function in 3 of the 10 DISD patients (30.0%). In the DISD group, 27 were older patients (3.2%). This was significantly more than the 15 who were younger patients (1.6%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A clinical study of drug-induced sinus node dysfunction]. 197 57

The role of temporary percutaneous endocardial pacing has been examined in a retrospective analysis of all paced patients admitted to one coronary care unit over a 6 year period. The majority of 162 cases (84.6%) were paced for complete heart block complicating acute myocardial infarction. These patients had a higher incidence of previous hypertension, myocardial infarction and diabetes, compared to matched controls (P less than 0.05, less than 0.02 and less than 0.001, respectively). Admission blood glucose levels were also higher (P less than 0.05). The in-hospital mortality was high (46.7%), especially for those with anterior myocardial infarction (74.5%). Twenty-five (15.4%) patients without recent myocardial infarction were paced for symptomatic brady-dysrhythmias, usually due to chronic complete heart block (Lenegre's disease) or sick sinus syndrome. Most later required permanent pacing. Complications of temporary pacing were more frequent in those who died, the most common being dysrhythmias during pacemaker insertion. Review of our cases suggests that whilst facilities for temporary pacing were extremely valuable, many cases treated were not haemodynamically compromised and probably did not require pacing. Guidelines should be established on coronary care units to prevent the unnecessary morbidity, mortality and expense of the procedure.
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PMID:Temporary transvenous cardiac pacing: 6 years experience in one coronary care unit. 259 96

A new class of beta-adrenergic blockers with the pharmacologic property of intrinsic sympathomimetic activity (ISA) is emerging for use in the treatment of hypertension. These agents decrease blood pressure and systemic vascular resistance, while the heart rate and cardiac output at rest are maintained. Beta blockers with ISA may be used in clinical situations where non-ISA beta blockers are relatively contraindicated, such as sinus bradycardia, sick sinus syndrome, Raynaud-like symptoms and chronic obstructive lung disease.
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PMID:Beta blockers with intrinsic sympathomimetic activity. 285 59

PN 200-110 (isradipine) is a new dihydropyridine calcium antagonist with selective actions on the heart as well as the peripheral circulation. It selectively inhibits the sinus node but not atrioventricular conduction and its negative inotropic action is minimal, about 20 times weaker than its negative chronotropic effect. This in vitro pattern also expresses itself in vivo: partial suppression of the reflex tachycardia induced by its peripheral vasodilatation and no effect on the P-Q interval on the electrocardiogram even at large doses. The presence of first- or second-degree heart block should therefore not limit its use, whereas the sick sinus syndrome might. PN 200-110 does not decrease myocardial contractile force even in vagotomized animals with full beta blockade. PN 200-110 nevertheless lowers myocardial oxygen consumption mainly by its action on afterload. It should therefore be useful in angina pectoris. PN 200-110 is a powerful peripheral vasodilator. It preferentially dilates coronary, cerebral and skeletal muscle vasculature. Its long lasting (24 to 48 hours) antihypertensive action is not accompanied by tachycardia in spontaneously hypertensive rats and it enhances sodium and water excretion in normotensive rats. It should be useful in the treatment of hypertension, and, considering its pattern of cardiac actions, perhaps also as an after-load-reducing agent for the treatment of heart failure. Antiarteriosclerotic effects in conscious rabbits were found at reasonably small doses, suggesting that such effects might occur in man at therapeutic doses.
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PMID:Selective effects of PN 200-110 (isradipine) on the peripheral circulation and the heart. 294 86

The mechanism of sinus node dysfunction caused by cardiac lymphostasis was studied in dogs with histological and electrophysiological methods. A total of seventeen mongrel dogs were used in this study. Out of them 12 animals were operated to induce cardiac lymphostasis and sacrificed 3, 6, and 10 days after operation. In 3 of the dogs, in addition to cardiac lymphostasis, local cardiac hypertension was induced by constricting the descending aorta (artificial coarctation of the aorta). The other five dogs were sacrificed as normal controls. The signs of deteriorated pacemaker function of the sinus nodes; sinus arrest escape rhythm, and bradycardia were observed in electrocardiographic (ECG) tracings in dogs with cardiac lymphostasis. The sinus node cells of the animals revealed cytoplasmic oedema, and swelling of the cells developed progressively parallel to the time elapsed after the operation. The pathological changes in the animals with combined lymphostasis and local hypertension were more severe than those seen in the animals with lymphostasis only. In one out of the three dogs with combined operation, scattered foci of necrobiotic sinus node cells and necrobiosis of the medial smooth muscle cells in sinus node arteries were also observed. It was concluded in the present study that cardiac lymphostasis induced water and electrolyte imbalance in sinus nodes. The disturbed water and electrolyte homeostasis resulted in alterations in the electrophysiological activity of the sinus nodes. In order to elucidate the exact relationship between cardiac lymphostasis and human sick sinus syndrome, further experimental and clinical studies will be necessary.
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PMID:Effects of cardiac lymphostasis on sinus nodes. A histological study in canine experiment. 311 44


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