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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Among various methods to treat ventricular tachyarrhythmia (VT) in the presence of acute myocardial infraction, the surgical approach is a somewhat unsatisfactory method in case of preoperative acute hemodynamic deterioration. The transatrial approach with the "topical" application of Lugol solution on left ventricular (LV) endocardium, without left ventriculotomy, i.e. a transatrial chemical ablation method; has been reported in our department as suggestive to being efficacious. The objective of the present study is to investigate the occurrence of left bundle branch block (LBBB) and the like, as well as to examine the impact on heart function, particularly LV function, by employing the just-above mentioned approach. 15 mongrel dogs were being experimented on. Through a left transatrial approach toward LV endocardium and the application of Lugol solution, with pulmonary artery flow being as constant; we measured pre- and post-operative left atrial (LA) pressure, LV pressure, aortic pressure, LV functional shortening, and stroke volume. In addition, the same protocol was also employed in another group, with the application of physiologic normal saline solution, instead. A comparative study was made between the two groups. In the Lugol solution group, postoperative LA pressure and LVEDP showed a tendency toward exhibiting higher values, when compared to preoperative readings. However, no significant difference was observed in this setting. Furthermore, in comparison with postoperative readings in the saline group, the mean LA pressure in the Lugol solution group exhibited a tendency toward somewhat higher values. Nonetheless, no significant difference was observed in LV functional shortening between the two groups; though it is known a LBB pattern could be noticed on ECG in the Lugol solution group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The effect of chemical ablation with lugol solution for ventricular tachyarrhythmia on cardiac function]. 229 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

Prospective data from Busselton, Western Australia, collected during triennial surveys from 1966-81 with follow-up of subjects to 1983, showed that atrial fibrillation (AF) was frequent in elderly people and associated with increased mortality. Of 1770 people aged over 60 years, 40 were in atrial fibrillation when first seen and a further 47 developed it during follow-up. Atrial fibrillation was positively associated with angina, history of a myocardial infarction and left bundle branch block. Relative mortality in those with atrial fibrillation compared with those without it, was 1.92 for all causes, 1.82 for death from cardiovascular causes (excluding stroke) and 3.78 for deaths from stroke, after adjustment by proportional hazards regression for confounding effects of age, sex, history of a myocardial infarction, an abnormal electrocardiogram, angina, cholesterol level systolic blood pressure and Quetelet's Index (weight/height2). The excess relative mortality declined with increasing age for both women and men. This raised relative mortality remained constant with time from the first detection of AF for all causes and cardiovascular causes but appeared to increase with time from detection for stroke death. The risk of death from stroke was greatest in the younger women. The observed risk of death from stroke in patients with AF suggests that anticoagulant use should be considered in selected patients.
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PMID:Atrial fibrillation and mortality in an elderly population. 278 8

The effects of atrioventricular (AV) sequential pacing-induced left bundle branch block (LBBB) on left ventricular (LV) performance were evaluated during cardiac catheterization in 9 randomly selected patients being investigated for chest pain. All patients were in normal sinus rhythm with a normal P-R interval and QRS duration. LV performance was assessed by both hemodynamic and angiographic measurements. The maximal rate of LV pressure increase (dP/dt), rate of maximal LV pressure decrease (-dP/dt), LV end-diastolic pressure (LVEDP), end-diastolic volume (LVEDV), end-systolic volume (LVESV), stroke volume and percent ejection (EF) were measured during right atrial and AV sequential pacing at a constant pacing rate. The average pacing rate was 97 +/- 3 beats/min (mean +/- standard error of the mean). In each patient, both dP/dt and -dP/dt decreased significantly (p less than 0.001) during AV sequential pacing compared with atrial pacing at the same rate, from 1,541 +/- 68 to 1,319 +/- 56 mm Hg/s for dP/dt and from 1,506 +/- 86 to 1,276 +/- 92 for -dP/dt. LVEDP did not change significantly when atrial (17 +/- 3 mm Hg) and AV sequential pacing (16 +/- 2 mm Hg) were compared. Mean LVEDV did not change during atrial (135 +/- 13 ml) or AV sequential pacing (137 +/- 14 ml). In contrast, the LVESV during AV sequential pacing was higher by 15 ml (23%) (from 48 +/- 10 to 63 +/- 12 ml) (p less than 0.001); as a result, the stroke volume was lower by 13 ml (15%) and the EF decreased by 10%, from 66 to 56% (-15%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Alteration of left ventricular performance by left bundle branch block simulated with atrioventricular sequential pacing. 669 Dec 84

The clinical effectiveness of flecainide acetate was evaluated in 36 patients (29 male and 7 female, average age 56 years) in whom therapy with previous antiarrhythmic agents had failed. All patients had documented ventricular tachycardia on Holter electrocardiographic recording and 31 of 36 (86%) had had syncope or required cardiopulmonary resuscitation, or both. Angiographic findings demonstrated significant coronary artery disease in 22 (61%) and primary left ventricular dysfunction in 14 (39%), with a left ventricular ejection of 0.39 +/- 0.4. Patients were treated with an average flecainide dose of 302 +/- 76 mg/day. The follow-up time was 101 +/- 156 days. Thirty-two of 36 patients (89%) had complete elimination of ventricular tachycardia from Holter monitoring and only 2 patients had flecainide discontinued because of noncardiac side effects (numbness, blurred vision and ataxia). However, the drug was subsequently discontinued in 5 patients because of cardiac side effects (proarrhythmic effect in 2, sinus bradycardia in 1, complete atrioventricular block in 1 and new left bundle branch block in 1) and 10 patients died during flecainide therapy (1 with cerebral stroke, 3 with congestive heart failure and 6 with incessant ventricular tachycardia). A comparison of the general cardiac features of those who died with those who did not revealed a significantly lower ejection fraction (0.24 +/- 0.1 vs 0.45 +/- 0.1, p less than 0.05) and a significantly higher flecainide dose (350 +/- 85 versus 276 +/- 59 mg/day, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of flecainide acetate in the management of patients at high risk of sudden cardiac death. 669 14

Exercise tests were performed on 50 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 19 patients with hypertrophic nonobstructive cardiomyopathy (HNCM) of NYHA classes I to IV, and on 16 patients with congestive cardiomyopathy (CCM) of NYHA classes III and IV as well as, for detection of latent cardiomyopathy (LCM), i.e. functional impairment during exercise with normal findings at rest, on 102 patients with typical or atypical angina pectoris and ECG abnormalities of unknown etiology (left bundle branch block or ST segment depression) but normal coronary arteries and normal left and right ventriculogram. Measurements included heart rate, stroke volume, cardiac output, pulmonary artery pressure and minimal cardiac transit times of Indium-113m. Furthermore, in a large number of patients with latent cardiomyopathy, thallium-201 myocardial imaging and measurements of myocardial lactate extraction during high-rate atrial pacing were performed. The findings suggest that 1. the functional classification based on the patients' complaints often differs from the grade of hemodynamic impairment detected by exercise testing, 2. therapeutic effects (propranolol or surgery in HOCM, prazosin in CCM) are more pronounced under exercise as compared with resting conditions. Latent cardiomyopathy can be diagnosed only by detection of impaired function during exercise (increased pulmonary artery pressure, impaired myocardial lactate extraction during high-rate stimulation), since ventricular function and hemodynamics are normal at rest.
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PMID:[Exercise studies in patients with cardiomyopathy (author's transl)]. 720 Sep 43

The potentially adverse influence of premature ectopic beats or tachyarrhythmias on cardiac performance was studied by assessing the echocardiographic left ventricular stroke volume in 21 patients with cardiac rhythm disturbances. The beat to beat stroke volume correlated closely with end-diastolic volume in each patient (average R = .9). Premature ventricular contractions decreased stroke volume by an average of 48 +/- 8 ml (-71%) compared with sinus beats; whereas the postextrasystolic beats, although preceded by a pause and higher end-diastolic volume, increased stroke volume by only 16 +/- 7 ml (18%) over the sinus beats. Those postextrasystolic beats with equivalent timing and end-diastolic volume to the sinus beats had a mean stroke volume only 8 ml higher, suggesting that postextrasystolic potentiation plays only a minor role in augmenting stroke volume. Transient aberrant ventricular conduction of intermittent left bundle branch block, ectopic beats or atrial fibrillation failed to alter stroke volume. Ventricular bigeminy, trigeminy and quadrigeminy lowered cardiac output by 1.3, .9 and .7 l/min. The onset of tachyarrhythmias was oftentimes associated with a continuously changing end-diastolic volume and stroke volume, with either alternation or progressive increment of these variables. It is apparent that premature contractions decrease stroke volume by virtue of their infringement on diastolic filing, the principle beat to be determinant of stroke volume in arrhythmias being left ventricular end-diastolic volume. Since premature beats decrease stroke volume to an extent greater than postextrasystolic beats increase it, they may reduce cardiac output by a substantial degree, depending on their frequency of occurrence and degree of prematurity.
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PMID:The influence of ectopic beats and tachyarrhythmias on stroke volume and cardiac output. 726 99

In sum, systolic dysfunction of the ventricle associated with left ventricular outlet obstruction and often with mitral valve regurgitation may be improved by myotomy, myomectomy, mitral valve replacement, and perhaps by the creation of left bundle branch block via DDD right ventricular pacing. Diastolic dysfunction of the ventricle may be improved by prolonging the diastolic filling period, shortening the isovolumic relaxation period with calcium channel blocking drugs, or perhaps by altering the atrioventricular activation time with a DDD pacemaker. The symptoms and complications of associated arrhythmias may be improved by medication, particularly with beta-blockers, which tend to stabilize the atrial rhythm and perhaps the ventricular rhythms. In treating patients with demonstrated ventricular arrhythmias, other antiarrhythmic agents may be helpful. (Table II summarizes the abnormalities, causes, and treatments of hypertrophic obstructive cardiomyopathy.) Epicardial coronary atherosclerosis is not rare in these patients, and arteriographic confirmation may lead to improvement by surgical bypass treatment. Since stroke volume is nearly fixed, cardiac output depends very much on heart rate. For this reason, each patient needs to receive the appropriate dosage of medications to achieve the optimal heart rate for his or her own physiologic state.
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PMID:Potential mechanisms of improvement after various treatments for hypertrophic obstructive cardiomyopathy. 764 95

Bioimpedance offers a simple non-invasive means of measuring systolic ejection volume and heart rate and thus cardiac output. Four pairs of electrodes are placed on precise locations on the chest and stroke volume is calculated according to the equation developed by Kubicek in 1966 and modified by Sramek in 1980. The aim of this work was to evaluate this method in patients with heart disease. In a series of 50 patients, the coefficient of correlation for cardiac index between impedance values (2.52 +/- 0.71 ml/min/m2) and thermodilution values (2.74 +/- 0.69 ml/min/m2) was 0.63 (p < 0.01). The mean difference was -0.2 l/min/m2 (confidence interval +1 l/min/m2 to -1.4 l/min/m2). There was no statistical correlation in patients with complete left bundle branch block, severe mitral or aortic regurgitation or dilatation of the aorta. In a group of 11 healthy volunteers, there was a good correlation between two measures taken at a 2 day interval (r = 0.95). The coefficient of variation ranged from 1.2 to 7% for ejection volume. Bioimpedance is reproducible and simple, authorizing its use for non-invasive monitoring of cardiac output in a given patient in various clinical situations.
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PMID:[Thoracic electric bioimpedance. A non-invasive method for the measurement of cardiac output]. 774 18


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