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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Right ventricular (RV) systolic time intervals and hemodynamic parameters were determined by micromanometric techniques in 13 subjects with normal right ventricles (NRV). These data were compared to those of 16 patients with pulmonary hypertension (PH) or predominant pressure overloading and 13 individuals with uncomplicated secundum atrial septal defects (ASD) or predominant volume overloading. In PH, the QP2 interval tends to remain within the normal range due to reciprocal changes in isovolumic contraction (ICT) and ejection (RVET) times. Elevations of pulmonary artery diastolic pressure are associated with increases in the mean rate of isovolumic pressure rise (MRIPR) (r = 0.84), but the latter change does not fully compensate for the widened ventriculoarterial diastolic pressure difference and ICT becomes prolonged (P less than 0.001). Factors other than stroke index depression which may contribute to the decreased duration of RVET (P less than 0.001) include tricuspid regurgitation and elevation of pulmonary vascular impedance. In ASD, QP2 is significantly prolonged (P less than 0.025) due to a significant increase in RVET (P less than 0.005). In contrast to NRV, a linear correlation of RVET and stroke index was not present, which suggested an alteration of ejection dynamics in this group. Despite a high incidence of complete or incomplete right bundle branch block the interval from QRS onset to rapid RV pressure upstroke was not prolonged. This is most probably the result of peripheral bundle branch block of genesis of the QRS pattern by right ventricular hypertrophy.
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PMID:Alterations of right ventricular systolic time intervals by chronic pressure and volume overloading. 126 38

The ECG is useful in diagnosing acute myocardial infarction and unrecognized Q-wave myocardial infarction in the elderly. Unrecognized myocardial infarction and myocardial infarction associated with clinical symptoms have a similar incidence of new coronary events. Ischemic ST-segment depression on the resting ECG is associated with an increased incidence of new coronary events. The ECG is useful in the diagnosis of LV hypertrophy but is less sensitive and less specific than echocardiography in diagnosing LV hypertrophy. ECG LV hypertrophy is associated with an increased incidence of cardiovascular events in the elderly. However, echocardiographic LV hypertrophy is more sensitive in predicting new coronary events, atherothrombotic brain infarction, and congestive heart failure than is ECG LV hypertrophy. The ECG is also useful in diagnosing conduction defects and arrhythmias in the elderly. In the elderly, left bundle branch block, intraventricular conduction defect, Type II second-degree atrioventricular block, and pacer rhythm are associated with an increased incidence of new cardiac events, whereas right bundle branch block, left anterior fascicular block, and first-degree atrioventricular block are not. In the elderly, atrial fibrillation is associated with an increased incidence of thromboembolic stroke and new cardiac events. Premature atrial complexes and paroxysmal supraventricular tachycardia are not associated with an increased cardiac risk. Complex ventricular arrhythmias on the resting ECG are associated with an increased incidence of cardiac events in elderly patients with heart disease but not in elderly patients without heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Usefulness of the resting electrocardiogram in the elderly. 147 52

To investigate hemodynamic changes in ventricular premature contractions (VPCs), the blood flow velocities at the left ventricular (LV) outflow and inflow tracts were analyzed by pulsed Doppler echocardiography in 23 patients with VPCs and in two patients with ventricular parasystoles. Percent LV stroke volume of the ectopic and the postectopic sinus beats to the other sinus beats and %LV inflow volume of the sinus beats preceding ectopic beats to the other sinus beats were calculated from the time integral of the blood flow velocity. The following results were obtained. The %LV stroke volume of VPCs or %LV inflow volume of the preceding sinus beats correlated positively with the coupling interval of VPCs (r = 0.69, p less than 0.001 and r = 0.67, p less than 0.001, respectively). The %LV stroke volume of VPCs correlated positively with %LV inflow volume of the preceding sinus beats (r = 0.84, p less than 0.001). In some patients with VPCs of the RBBB pattern and in one patient with VPCs of the LBBB pattern associated with abnormal right axis deviation, the %LV stroke volume of VPC was much more reduced. In patients with depressed rapid filling and increased atrial filling, %LV stroke volume of the VPC or %LV inflow volume of the preceding sinus beat was smaller than in the other patients with the same coupling interval of VPCs. In VPCs of right ventricular (RV) origin, deterioration of RV hemodynamics was more prominent than in those of LV origin, and vice versa. Increased LV stroke volume was observed in postextrasystolic sinus beats, related to the coupling intervals of VPCs. However, the sum of %LV stroke volume of VPC and the postextrasystolic sinus beat decreased as the coupling intervals of VPC shortened. These results suggest that not only the coupling interval and the origin of VPCs but the LV diastolic behavior, as well, are important factors determining the hemodynamics in VPCs. They also suggest that the increment of stroke volume in postextrasystolic beats is more prominent in VPCs with shorter coupling intervals, but the LV performance as a whole is more depressed in VPCs with a shorter coupling intervals. In conclusion, pulsed Doppler echocardiography proved a useful noninvasive technique for evaluating the hemodynamics of VPCs.
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PMID:[Pulsed Doppler echocardiographic evaluation of hemodynamics in premature ventricular contractions]. 244 82

Cardiodynamic effects of acute experimental right bundle branch block (RBBB) were studied in canine hearts: group A included 15 normal hearts; group B-1 had seven hearts with mild right ventricular hypertrophy (RVH), and group B-2 had 11 hearts with marked RVH. The main sequential changes following RBBB were marked prolongation of the Q upstroke interval of the right ventricle and striking shortening of right ventricular systolic time that affected right and left ventricular interaction, particularly in the hearts with RVH. Hemodynamic changes were: the right ventricular end-diastolic pressure was elevated markedly (4.4 +/- 2.2----9.8 +/- 2.6 mm Hg, p less than 0.001) in group B-2, moderately (p less than 0.01) in group B-1, and not at all in group A. The right ventricular positive peak dp/dt decreased remarkably (1036 +/- 151----827 +/- 152 mm Hg/sec, p less than 0.001) in group B-2 and negligibly in the other groups. A significant correlation existed between the percentage of decrease in right ventricular peak dp/dt and the QRS duration of RBBB in each group (p less than 0.01). The left ventricular peak negative dp/dt decreased distinctly (2570 +/- 326----+/- 2055 +/- 362 mm Hg/sec, p less than 0.01) in group B-2 and not at all in the other groups. The stroke volume showed 12% decrease in group B-2 (p less than 0.001), 8% decrease in group B-1 (NS), and no decrease in group A. In the presence of RVH, acute RBBB causes significant impairment of right and left ventricular function. The magnitude of the impairment invariably depends upon both the prior degree of RVH and the width of the QRS complex.
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PMID:Cardiodynamic effects of experimental right bundle branch block in canine hearts with normal and hypertrophied right ventricles. 315 84

The electrocardiograms (ECGs) of 558 individuals, 83% of the total population aged 85 years or over in the city of Tampere in 1977, were assessed according to the Minnesota code in a health survey. The underlying causes of death were identified from the death certificates during the following five years. The total mortality rate was 70%, while the cardiovascular mortality was 51%. The lowest 5-year mortality from cardiovascular and cardiac diseases was observed in subjects with no codable or only minor ECG abnormality in the initial examination. The highest cardiovascular mortality rate was found in individuals with atrial fibrillation, atrioventricular blocks and left or right bundle branch block. The cardiac mortality was related to left or right bundle branch block and atrial fibrillation. Mortality from stroke showed the highest association with clockwise rotation and left high R waves.
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PMID:Electrocardiographic findings and 5-year cardiovascular mortality in very old people. 344 97

The cardiac output has been determined by radionuclide angiocardiography and by impedance cardiography in 93 elderly patients. The agreement between the two methods was excellent in patients in sinus rhythm, without regurgitant valvular lesions, and without severe airways obstruction or right bundle branch block. In atrial fibrillation the lack of correlation may be due to differences in heart rate during the two measurements, in regurgitant valvular lesions to the fact that impedance cardiography measures stroke output, whether forward or backward, in airways obstruction to high values for the basal thoracic impedance, and in right bundle branch block perhaps to the abnormal impedance wave-form often present.
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PMID:Accuracy of the impedance cardiogram in the measurement of cardiac output in the elderly. 405 Jun 5

Thirty-six of 42 consecutive patients who underwent corrective surgery for tetralogy of Fallot were operated upon without or with minimum right ventriculotomy and with repair of the pulmonary valve. The other six patients underwent conventional right ventriculotomy primarily because they required external valved conduits for repair. One of the 36 patients (2.8%) died 11 days postoperatively. Postoperative hemodynamic and angiocardiographic studies were performed randomly in eight patients. The results were compared with those obtained from 21 control patients who underwent conventional corrective surgery with right ventriculotomy and without repair of pulmonary valve. There were no differences in the degree of residual pulmonary stenosis. Moderate-to-severe pulmonary regurgitation occurred in none of the patients who underwent the new procedures and in 24% of the controls. Cardiac and stroke volume indexes at rest measured postoperatively did not differ significantly between the two series of patients. The cardiac index for both series of patients increased significantly during isoproterenol infusion, measuring 7.29 +/- 1.97 l/min/m2 for the present series of patients (p less than 0.005) and 5.76 +/- 1.64 l/min/m2 for the controls (p less than 0.001). These two values were significntly different (p less than 0.05). Stroke volume index in the present series of patients increased significantly during isoproterenol infusions., from 37 +/- 5 ml/m2 to 45 +/- 15 ml/m2 (p less than 0.05), whereas that for the controls decreased significantly, from 43 +/- 10 ml/m2 to 38 +/- 12 ml/m2 (p less than 0.01). These differences in the response to isoproterenol infusion in the two series of patients indicated that right ventricular function after corrective surgery for tetralogy of Fallot was well maintained in patients who underwent the new method of operation. The two series of patients did not differ with respect to the development of right bundle branch block.
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PMID:Corrective surgery for tetralogy of Fallot without or with minimal right ventriculotomy and with repair of the pulmonary valve. 724 16

Malposition of pacemaker leads has been described in several locations but rarely in the left ventricle. The incidence and clinical course of this pacemaker complication are unknown. We describe clinical, electrocardiographic, chest X ray, and echocardiographic findings in four patients in whom the transvenous pacing lead was inadvertently placed through the interatrial septum and mitral valve into the left ventricle. In these patients, lead misplacement was not recognized at the time of implantation and lead malposition was diagnosed a mean of 2 years later. All four patients had right bundle branch block configuration paced complexes. In retrospect, chest X rays suggested atypical lead position in all, but the initial posterior-anterior and lateral chest X rays were misinterpreted and contributed to the delay in diagnosis. When lead misplacement in the left ventricle was considered it was confirmed by two-dimensional echocardiography. One patient subsequently presented with a stroke and the remainder were diagnosed when they presented with other unrelated problems. Pacing thresholds were normal at the time of implantation and behaved normally during follow-up. The patient presenting with stroke was anticoagulated and the other three have been managed expectantly without anticoagulation. Diagnosis of left ventricular lead malposition is not difficult but requires a high index of suspicion. A 12-lead ECG and posterior-anterior and lateral chest X rays after implantation can be diagnostic. Patients with pacing lead in the left ventricle may remain asymptomatic with normal lead function during long-term follow-up. Anticoagulation should be considered when this problem comes to attention for the first time during follow-up.
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PMID:Malposition of transvenous pacing lead in the left ventricle. 769 12

A 32-year-old woman developed chronic progressive hearing impairment, trunkal ataxia, bilateral ptosis and external ophthalmoplegia. She also showed slowly progressive mild to moderate proximal dominant muscle weakness and atrophy. ECG showed incomplete right bundle branch block. An aerobic exercise test showed abnormal blood lactate elevation and muscle biopsy revealed ragged-red fibers in addition to the myopathic change. Analysis of mitochondrial DNA extracted from biopsied muscle and fibroblast samples revealed a 1,758bp deletion from the cytochrome b to ND6 coding regions. Common mutations in tRNALeu(UUR) coding region to the mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) were not present. She was diagnosed as having incomplete Kearns-Sayre syndrome (KSS). Since the age of 35, she developed complex partial seizure attacks with secondary generalization frequently and at the age of 42, she had a severe generalized seizure with delayed consciousness loss followed by left hemiplegia. MRI showed wide T2-high signal lesions in the right temporo-parieto-occipital area. The proton MR-spectroscopy showed prominent increase of lactate beyond the lesions detected by MRI, indicating diffuse aerobic metabolic dysfunction in the central nervous system. We reviewed two other KSS cases with a stroke like episode, who also had epilepsy and large deletion but no tRNALeu(UUR) mutation, in mitochondrial DNA. Patients with KSS who have seizure may develop the stroke-like episode as seen in MELAS patients.
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PMID:[A case of incomplete Kearns-Sayre syndrome with a stroke like episode]. 940 43

Combined alteration of the pyruvate dehydrogenase complex and respiratory chain function is described in a 21 year-old male patient with overlapping MELAS (mitochondrial encephalomyopathy, lactic acidosis, and 'stroke-like' episodes) and Kearns-Sayre syndrome. Progressive external ophthalmoplegia, pigmentary retinopathy and right bundle branch block were present when he experienced the first 'stroke-like' episode at 18 years old. The A>G tRNALeu(UUR) point mutation at nucleotide 3243 of the mitochondrial DNA was predominant in muscle tissue (79%) and present, but at lower levels in fibroblasts (49%) and blood cells (37%). Biochemical analysis revealed diminished activities of pyruvate dehydrogenase (23%) and respiratory chain complexes I and IV (57%, respectively) in muscle, but normal activities in the fibroblasts. Immunochemical studies of the muscular pyruvate dehydrogenase components showed normal content of E1alpha, E1beta and E2 protein. Molecular screening of the E1alpha gene did not indicate a nuclear mutation. These observations suggest that mitochondrial DNA defects may be associated with altered nuclear encoded enzymes which are actively imported into mitochondria and constitute components of the mitochondrial matrix. Biochemical workup of mitochondrial disorders should not be restricted to the respiratory chain even if mitochondrial DNA mutations are present.
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PMID:Pyruvate dehydrogenase complex deficiency and altered respiratory chain function in a patient with Kearns-Sayre/MELAS overlap syndrome and A3243G mtDNA mutation. 961 47


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