Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In our approach to dynamic cardiomyoplasty, which consists of wrapping a skeletal muscle around the heart and stimulating the former in synchrony with heart contractions to augment ventricular contractility, we have transferred a latissimus dorsi muscle flap to the heart by way of a partial resection of the second rib and subsequently suturing the muscle flap around the ventricles. The muscle flap is stimulated by a Cardio-Myostimulator burst-pulse generator (Medtronic SP 1005) connected to intramuscular electrodes. In preclinical animal research, the latissimus dorsi muscle flap was shown to maintain adequate contractile force and to increase its fatigue resistance by gradual conversion of glycolytic-fatigue-sensitive-to-oxidative-fatigue-resistant muscular fibers (100%). Histochemical and biochemical studies of chronically stimulated muscles showed a total transformation of muscle fast myosin to slow myosin with characteristics similar to those of myocardium. Electron microscopy showed preserved myofibrillar cytoarchitecture and increased mitochondrial density in the cell. At 9 months, cardiac output and ultrasonic Doppler studies showed a significant increase in ventricular function (cardiac output, +21%; peak blood velocity, +40% -80%; and stroke volume, +98% -102%) during muscle stimulation. In the clinical situation, long-term (range of follow-up interval, 4-42 months) beneficial cardiac effects of cardiomyoplasty have been documented in eight patients with various pathologies (ventricular tumor, left ventricular aneurysm, ischemic disease, and dilated cardiomyopathy). Our current understanding of this process is that dynamic cardiomyoplasty acts in two ways: 1) it promotes more vigorous systolic contraction, and 2) it appears to limit heart dilatation.
 ...
PMID:Effect of latissimus dorsi dynamic cardiomyoplasty on ventricular function. 318 Apr

The administration of beta-blocking agents to patients with poor left ventricular (LV) function may result in clinical and hemodynamic deterioration. The beta antagonist pindolol has intrinsic sympathomimetic activity (ISA) and therefore may be better tolerated. To test this hypothesis 30 patients with a precatheterization diagnosis of dilated cardiomyopathy were randomly assigned to three groups to receive intravenous injections of placebo, propranolol, or pindolol. The baseline ejection fraction and hemodynamics were similar for all groups. For propranolol 1 mg, 2 mg, 3 mg, and 4 mg doses were given 5 minutes apart until a maximum dose of 10 mg was reached, until a 25% reduction in the heart rate or mean arterial pressure occurred, or until clinical deterioration developed. For pindolol, 0.1 mg, 0.2 mg, 0.3 mg, and 0.4 mg boluses were used with the same end points. Baseline hemodynamics were measured and repeated 15 minutes after the last dose of each drug was administered. The mean number of doses given was similar for both groups: 3.3 doses for the propranolol group and 3.4 for the pindolol group. Compared to propranolol, pindolol caused less of a reduction in heart rate, cardiac output, cardiac index, stroke volume index, and stroke work index and less of an increase in the mean right atrial pressure, mean pulmonary arterial pressure, mean pulmonary capillary wedge pressure, left ventricular end-diastolic pressure, and pulmonary vascular resistance; there was a decrease in systemic vascular resistance. These differences were statistically significant for changes in heart rate, right atrial pressure, cardiac index, and systemic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Acute hemodynamic effects of pindolol and propranolol in patients with dilated cardiomyopathy: relevance of intrinsic sympathomimetic activity. 318 43

In atrial fibrillation, the relation between the rhythm and volume of the pulse has long been of interest. However, changes in preload in this condition have not been fully addressed since beat to beat measurement of filling volume have been difficult until recently. In the present study, we evaluated left ventricular outflow and inflow velocity using pulsed Doppler echocardiography and correlated these results with the R-R interval in the individual patient. The study population consisted of 12 patients with atrial fibrillation, aged 36 to 69 years (mean 54 years). The etiology of atrial fibrillation was idiopathic in 10 and 2 patients had dilated cardiomyopathy. Stroke and filling volume were calculated as a pruduct of the flow velocity integral of left ventricular outflow and inflow velocity, and the cross-sectional area of aortic and mitral annulus, respectively. In 10 patients with idiopathic atrial fibrillation, significant positive correlations were observed between the preceding R-R interval and both the stroke volume and the filling volume of the preceding beat when the R-R interval was shorter than 600 msec. Stroke volume and filling volume of the preceding beat were almost constant, independent of the preceding R-R interval when the preceding R-R interval was longer than 600 msec, the interval necessary for the completion of the preceding rapid filling. In the same preceding R-R interval, a larger stroke volume was observed in a shorter pre-preceding R-R interval. In 2 patients with dilated cardiomyopathy no relationship could be observed between the preceding R-R interval and the filling volume of the preceding beat or the stroke volume. In patients with a normally functioning left ventricle (idiopathic atrial fibrillation), reduced cycle length and filling volume in the preceding cardiac cycle appear to be the underlying cause of the regulation of stroke volume, dependent on Starling's law. However, in patients with dilated cardiomyopathy no significant correlation was observed between the preceding R-R interval and both the filling volume of the preceding beat and the stroke volume. In these patients the left ventricle may have limited contractile reserve and altered diastolic re-coil forces possibly due to degenerative changes of myocardium. Pulsed Doppler echocardiography provides a non-invasive method of evaluating the instantaneous changes in left ventricular flow dynamics caused by atrial fibrillation and understanding its fundamental mechanism.
 ...
PMID:Relationship between beat to beat interval and left ventricular function in patients with atrial fibrillation. 324 36

In the present study 12 patients with severe chronic heart failure (7 with dilated cardiomyopathy and 5 with ischaemic heart disease) underwent right heart catheterization at rest and during isometric exercise by handgrip before and 6 months after treatment with captopril (mean dose 2 X 39.6 mg/day) while concomitant digitalis and diuretics were unchanged. After 6 months resting haemodynamics changed as follows: decrease in heart rate, mean arterial pressure, pulmonary capillary pressure and total vascular resistance; increase in stroke volume index and stroke work index. During handgrip the following changes were observed after captopril: decrease in total vascular resistance; increase in stroke volume index and stroke work index. Before captopril 11 patients showed no increase or even a decrease in stroke work index during isometric exercise, whereas after captopril 5 out of the 12 patients showed an increase in stroke work index. The results demonstrate that in patients with severe chronic heart failure long-term treatment with captopril lowers preload and afterload, which is accompanied by a significant improvement in left ventricular performance at rest. Furthermore, during isometric exercise after captopril an improvement in left ventricular function was found in 5 out of 12 patients.
 ...
PMID:Haemodynamics at rest and during isometric exercise under long-term treatment with captopril in dilated and ischaemic cardiomyopathy. 330 89

Although the success of cardiac transplantation has encouraged earlier referral of potential candidates, those with mild symptoms of heart failure are frequently considered "too well" for transplantation. Outcome was investigated for 28 patients with non-ischemic dilated cardiomyopathy and ejection fraction of 25 percent or less who were denied transplantation due to lack of severe symptoms. One-year survival without transplantation was 46 percent. Low stroke volume and history of ventricular arrhythmias were independent predictors of early mortality. High risk, defined as either stroke volume of 40 ml or less or history of ventricular arrhythmia, identified 13 of 14 patients who did not survive one year and only one of 12 one-year survivors (p less than 0.001). Low stroke volume predicted hemodynamic failure (p less than 0.05) whereas arrhythmic history predicted sudden death (p less than 0.001). Clinical status improved in only six patients, all of whom had symptom duration of seven or less months at initial evaluation (p less than 0.001). Thus, patients referred to transplantation for dilated cardiomyopathy with an ejection fraction of 25 percent or less have a poor prognosis even if symptoms are mild. Patients with high hemodynamic risk may require early transplantation, whereas those with high arrhythmia risk may require other aggressive therapy in order to avoid transplantation until symptoms become severe.
 ...
PMID:Poor survival of patients with idiopathic cardiomyopathy considered too well for transplantation. 331 98

This 3-part discussion of captopril, the first oral angiotensin converting enzyme (ACE) inhibitor, focuses on the clinical use and superiority of this agent to standard treatments and the new observations that use can improve the overall poor survival associated with heart failure. Today, as in the past, treatment of CHF includes digoxin and diuretics. Vasodilators have been relegated by some to the role of supplementing therapeutic regimens when patients remain symptomatic. Recently, controlled studies have shown that the introduction and supplementation of therapeutic regimens with ACE inhibitions and specifically captopril is associated with substantial clinical benefits: Symptoms are reduced as hemodynamics and exercise capacity improve, metabolic derangements (including fluid retention, potassium and magnesium loss and sympathetic nervous activation) are reduced with resultant favourable effects on arrhythmia frequency and finally the newest and most dramatic observation of improved survival. This review will briefly summarize these developments and assist in the clinically important aspects of this therapy for practicing physicians. Guidelines for the clinical use of captopril: In patients with confirmed dilated cardiomyopathy, captopril improves stroke volume in response to afterload reduction, but in volume-contracted patients vasodilation may be associated with hypotension. Therefore, prior to initiating captopril, the diuretic dosage should be reduced, particularly in low serum sodium concentration states if intravascular volume is depleted. Potassium supplements should be stopped due to the expected decrease of aldosterone production and improved potassium retention. Initial therapy should be started with a low captopril dosage (2 to 3 times 6.25 mg/day), maintenance dosages are 25 or 50 mg b.i.d. or t.i.d. Superiority to other vasodilator drugs and use in mild cases: In studies of acute and chronic CHF, captopril improves hemodynamics, exercise tolerance, and reduces symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Captopril in the treatment of congestive heart failure. 332 93

Dopexamine hydrochloride (Dopacard) is a new synthetic catecholamine compound, which possesses potent beta 2-adrenergic and DA1-dopaminergic agonistic properties. It is free of alpha-adrenergic activity, has no beta 1-adrenergic activity and is less potent at DA2-dopaminergic receptors than dopamine. In the present study the acute haemodynamic effects of dopexamine hydrochloride were compared to those of dobutamine and nitroprusside in 12 patients with idiopathic congestive cardiomyopathy in an open crossover study. With dopexamine hydrochloride, there were dose-dependent increases from control in cardiac output and stroke volume, decreases in blood pressure, right and left atrial pressure, systemic vascular resistance and pulmonary vascular resistance and little change in heart rate. Similar effects were seen with nitroprusside, apart from a marked increase in heart rate, and with dobutamine, except that systolic aortic blood pressure increased and there was no change in diastolic or mean pressure or pulmonary artery systolic pressure. In general, dopexamine hydrochloride produced effects between those produced by the other two treatments. This suggests that dopexamine with its combined vasodilator and inotropic action has a desirable cardiovascular profile with advantages over the beta 1-receptor agonist dobutamine and the pure vasodilator sodium nitroprusside.
 ...
PMID:Comparison of acute haemodynamic effects of dopexamine hydrochloride, dobutamine and sodium nitroprusside in chronic heart failure. 340 66

The presence and severity of functional mitral regurgitation were quantified by Doppler echocardiography in 17 patients with dilated cardiomyopathy and no evidence of primary valvular disease. Mitral regurgitant fraction was greater than 20% in 11 of the 17 patients, and exceeded 40% in four patients. Total stroke volume, calculated from the difference between end-diastolic and end-systolic volumes obtained by two-dimensional echocardiography, correlated well with mitral valve inflow determined by Doppler echocardiography (r = 0.90, p less than 0.001). Similarly, mitral regurgitant volume, calculated as the difference between echocardiographic total stroke volume and forward aortic volume obtained by Doppler echocardiography, correlated well with regurgitant volume calculated as the difference between mitral valve inflow and forward aortic flow, both determined by Doppler echocardiography (r = 0.90, p less than 0.001). Accordingly, functional mitral regurgitation can be conveniently demonstrated in patients with dilated cardiomyopathy by two different Doppler echocardiography methods, whose results are closely correlated. Mitral regurgitant fraction is greater than 20% in two thirds of the patients with a dilated cardiomyopathy.
 ...
PMID:Noninvasive quantification of mitral regurgitation in dilated cardiomyopathy: correlation of two Doppler echocardiographic methods. 341 90

Cardiac function is difficult to assess in patients with atrial fibrillation due to the widely fluctuating cycle lengths resulting in variable ventricular hemodynamics. With respect to ECG-gated blood pool scintigraphy, distortion of the time activity curve occurs due to a summation of irregular cycle lengths. Therefore, performing such a study has been regarded meaningless. To evaluate left ventricular function during atrial fibrillation using scintigraphic technique, a new processing algorithm was devised to make multiple gated images which are discriminated by the preceding R-R interval, and left ventricular filling and function curves were established. The left ventricular filling curve, obtained by plotting end-diastolic volume against the preceding R-R intervals demonstrated an impairment of blood filling in cases of mitral stenosis and constrictive pericarditis, which resolved after mitral commissurotomy in case of mitral stenosis. The left ventricular function curve, established by plotting stroke volume against end-diastolic volume, was analyzed according to indices such as "slope" and "position". Both of these indices were significantly reduced in relation to the severity of heart failure according to the NYHA's functional classification and cardiomegaly on chest radiography. On individual comparisons of underlying diseases, the indices decreased in the following order; lone atrial fibrillation, hyperthyroidism, aging, hypertension, mitral valve disease, ischemic heart disease, dilated cardiomyopathy and aortic regurgitation. The indices correlated closely with ejection fraction. In cases of mitral regurgitation, however, the function curves were situated to the right and above those of lone atrial fibrillation and decreased in slope despite the fairly well-maintained ejection fraction. After treatment with digitalis and/or diuretics, the function curves shifted to the left and upward. In conclusion, left ventricular filling and function curves based on a newly-devised algorithm of ECG-gated blood pool scintigraphy are of considerable clinical value in evaluating cardiac performance in patients with atrial fibrillation. They are widely applicable to the assessment of therapeutic and interventional effects.
 ...
PMID:[Left ventricular function during atrial fibrillation assessed by left ventricular function curve using ECG-gated blood pool scintigraphy]. 350 42

To examine the effects of acute oral milrinone administration (0.75 mg/kg) on dogs with severe idiopathic myocardial failure and the effect of prolonged milrinone administration on survival time, we measured hemodynamics before and 2 hours after drug administration and recorded survival time and cause of death in 13 dogs with dilated cardiomyopathy. Hemodynamics were measured using a Swan-Ganz catheter and femoral artery puncture along with recording an M-mode echocardiogram. Cardiac index increased from 1.92 +/- 0.54 to 3.06 +/- 0.81 L/min/m2, stroke volume index increased from 11.3 +/- 4.3 to 16.7 +/- 6.3 ml/beat/m2, and pulmonary capillary wedge pressure decreased from 23 +/- 8 to 12 +/- 8 mmHg. A clinically significant increase in heart rate was observed in seven dogs, resulting in a statistically significant increase in heart rate for the group from 174 +/- 34 to 194 +/- 44 beats/minute. Mean arterial blood pressure did not change significantly for the group but did decrease more than 20 mmHg in three dogs, suggesting a predominant primary vasodilating effect of milrinone in these dogs. An increase in contractility appeared to be the predominant reason for the improved hemodynamics in seven dogs. Eight dogs died of causes other than worsening heart failure, including four of eight Doberman pinschers that died suddenly, presumably from an acute tachyarrhythmia. Two dogs that had the greatest increase in an index of contractility are alive more than 2 years after the initiation of milrinone administration.
 ...
PMID:The acute hemodynamic effects of milrinone in dogs with severe idiopathic myocardial failure. 350 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>