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

Electrocardiographic referenced repetitive gradient echo magnetic resonance imaging (cine GRE) has been used to detect and quantify valvular regurgitation. Regurgitation is recognized as a signal void in the high intensity blood pool on these images. Mitral regurgitation causes a signal void in the left atrium in systole, and aortic regurgitation produces one in the left ventricle in diastole. The specificity, sensitivity, and diagnostic accuracy of cine GRE for the detection of mitral and aortic regurgitation was greater than 0.93, 0.89, and 0.92, respectively. The severity of regurgitation has been quantified as the difference in the stroke volume between the two ventricles by measuring the volume of the blood pool, as shown in the stack of magnetic resonance tomograms. Severity has also been assessed by measuring the volume of the signal void. Finally, measurements of the volume of aortic regurgitation have recently been achieved by using velocity-encoded cine GRE. This technique provides a direct measurement of retrograde flow in the aorta during diastole. New cine GRE imaging techniques provide a noninvasive means for quantification of valvular as well as ventricular function.
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PMID:Evaluation of valvular heart disease with cine gradient echo magnetic resonance imaging. 188 87

From July 1986 to January 1991, 123 patients with Wolff-Parkinson-White syndrome underwent operation for ablation of aberrant conduction pathways. There were 85 male and 38 female patients ranging in age from 11 months to 68 years. Associated anomalies included Ebstein's anomaly, sudden death syndrome, coronary artery disease, cardiomyopathy, abdominal aortic aneurysm, neurofibromatosis, other arrhythmias, or other complex congenital heart disease. Forty-one patients had multiple accessory pathways. Operative results showed a 7% initial failure rate, which dropped to 3% after reoperation. One patient had undergone previous operation for Wolff-Parkinson-White syndrome at another institution. Procedures performed concomitantly included mitral or tricuspid valve repair or replacement (6), right ventricular conduit replacement, subaortic resection, Fontan repair, corrected transposition repair, coronary artery bypass, and placement of an automatic internal cardioverter defibrillator. There was no operative mortality. Late follow-up is 27 +/- 16 months, and complications included mitral regurgitation and myocardial infarction. By comparison, in the last 12 months 124 patients with the Wolff-Parkinson-White syndrome underwent catheter ablation using radiofrequency current. There were 9 patients with multiple pathways. One hundred twelve patients (90%) had all accessory atrioventricular connections ablated and have remained free of symptomatic tachycardia. There have been 12 failures (10%), of which 5 have had operation and 7 are being treated medically. Mean follow-up is 7 +/- 5 months, and complications included circumflex coronary artery occlusion, excessive bleeding, valve perforation, and cerebral vascular accident.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Current treatment for Wolff-Parkinson-White syndrome: results and surgical implications. 189 33

The response of left ventricular (LV) geometry to altered loading conditions after mitral valvuloplasty has been incompletely described. Therefore, 15 patients with rheumatic mitral stenosis were studied using quantitative 2-dimensional echocardiography a mean of 1 +/- 2 months before and 11 +/- 5 months after percutaneous balloon mitral valvuloplasty. Mitral valve area (Gorlin) increased in all patients, from 1.0 +/- 0.3 to 1.9 +/- 0.5 cm2 (p less than 0.01). Mitral regurgitation (1+/4+) developed in 3 patients, and increased by 1 grade in 1 patient as a consequence of mitral valvuloplasty. After valvuloplasty, there were significant increases in LV end-diastolic volume (69 +/- 22 to 82 +/- 26 ml, p less than 0.01), stroke volume (34 +/- 13 to 46 +/- 19 ml, p less than 0.05) and mass (181 +/- 46 to 200 +/- 42 ml, p less than 0.005). LV end-systolic volume and ejection fraction did not change significantly. LV mass-to-volume ratio was unchanged (5.6 +/- 1.5 to 5.8 +/- 1.4 g/ml, p = not significant). Quantitatively similar results were obtained when these changes were indexed to body surface area. Thus, successful mitral valvuloplasty was associated with significant increases in LV end-diastolic volume and mass. These findings suggest that increased preload may be a stimulus to myocardial growth.
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PMID:Effects of percutaneous mitral valvuloplasty on left ventricular mass and volume. 192 54

The importance of the mitral subvalvular apparatus in terms of left ventricular (LV) mechanics and energetic efficiency in the chronically dilated canine heart was assessed in nine dogs with surgically induced mitral regurgitation. Miniature radiopaque tantalum markers were implanted into the myocardium to measure LV volume. Biplane cinefluoroscopic images obtained 1 week and 3 months after creation of mitral regurgitation confirmed the presence of LV dilatation. Mitral valve replacement with preservation of all chordae tendineae was then performed. LV systolic function and derived energetics were then assessed during transient caval occlusion both before and after chordal division by using exteriorized snares. Global LV systolic mechanics, as assessed by the slopes of the end-systolic pressure volume (Ees) and end-systolic stress volume (Ms) relations, fell by 46% (11.7 +/- 2.8 versus 6.3 +/- 1.4 mm Hg/ml, p less than 0.001) and 33% (17.8 +/- 4.0 versus 12.0 +/- 5.1 kdyne/cm5, p = 0.0001), respectively, when the chordae were divided. Chordal severing also increased systolic LV wall stress or LV afterload. In terms of calculated myocardial energetics, the slopes of the stroke work-end-diastolic volume and pressure volume area-end-diastolic volume relations declined significantly by 20% (85 +/- 14 versus 68 +/- 16 mm Hg) and 11% (116 +/- 20 versus 104 +/- 20 mm Hg) after cutting the chordae, thereby indicating reduced external stroke work and mechanical energy generated at any given level of preload. Moreover, the efficiency of energy transfer from pressure volume area to external stroke work fell by 19% (p less than 0.001). Since effective systemic arterial elastance (Ea) did not change, the Ea/Ees ratio (index of ventriculoarterial [V-A] coupling) increased from 0.93 +/- 0.27 to 1.67 +/- 0.62 (p = 0.006). Therefore, chordal division in dilated dog hearts due to chronic mitral regurgitation resulted not only in deterioration of systolic LV mechanics but also deleterious changes in calculated LV energetics and efficiency due to exacerbated mismatch in V-A coupling between the left ventricle and the systemic arterial bed, unfavorable loading conditions, and exhaustion of preload reserve. These observations in the low-pressure, volume-overloaded heart due to chronic mitral regurgitation underscore the importance of the mitral subvalvular apparatus for optimal LV systolic performance and energetic efficiency.
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PMID:Mitral valve replacement in dilated canine hearts with chronic mitral regurgitation. Importance of the mitral subvalvular apparatus. 193 99

Although it is usually assumed that direct-acting vasodilators improve cardiac function in patients with congestive heart failure (CHF) by altering left ventricular preload and afterload, several studies have suggested that most of the benefit occurs as a result of a reduction in associated mitral regurgitation (MR), which is present in the majority of patients with severe CHF. To test his hypothesis, the hemodynamic response to oral hydralazine was examined in CHF patients with competent mitral prostheses (group 1) and patients with CHF due to severe MR and left ventricular dysfunction (group 2). Both groups demonstrated significant increases in cardiac, stroke volume, and stroke work indices, although these were greater in group 2. Only group 2 experienced a significant reduction in left ventricular filling pressure. Thus, the presence of MR is not essential for hemodynamic improvement but is associated with significantly greater responses.
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PMID:Does the magnitude of mitral regurgitation determine hemodynamic response to vasodilation in chronic congestive heart failure? 193 87

Radionuclide imaging is useful in the assessment of left and right ventricular function in patients with a variety of cardiac diseases. Measurements of particular interest in patients with mitral insufficiency concern the left ventricle: ejection fraction, end-systolic volume, end-systolic volume/end-systolic pressure ratio, and the right ventricle (mainly its ejection fraction). The ejection and filling parameters of the left ventricle as well as parameters of the left atrial volume curve can also be of interest. Quantification of mitral insufficiency relies on comparisons of total stroke volume of the left ventricle, determined relatively, or quantitatively, with the forward stroke volume. The latter is measured either as the right ventricular stroke volume (in the absence of pulmonary and tricuspid regurgitation) or as cardiac output divided by heart rate and is obtained using a radionuclide or an independent method. Severe mitral regurgitation, as demonstrated by a large regurgitant fraction, can occur in the presence or absence of increased end-diastolic volume. The regurgitant fraction is not heart-rate dependent and does not clearly decrease during exercise, although some variations appear to exist. Evaluation of right ventricular function during exercise can also contribute to the assessment of patients with mitral insufficiency. Quantitative radionuclide methods are useful to assess the severity of mitral regurgitation and its repercussions.
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PMID:Quantification of mitral insufficiency by radionuclide techniques. 193 15

A 26-year-old Ethiopian woman with past history of stroke, presented with complaints of weakness, dyspnea on exertion, headache, and orthopnea. She had severe hypertension, asynchronous pulses, radial-femoral lag, cardiomegaly, and left ventricular hypertrophy. Blood studies were normal. Arteriogram in America showed aortic and mitral incompetence, bilateral subclavian occlusion distal to the origin of the vertebral arteries, with occluded hepatic and superior mesenteric arteries. The infrarenal abdominal aorta and common and external iliac arteries were occluded bilaterally. Renal arteries were normal. Takayasu's arteritis, inactive, was diagnosed. She underwent bilateral carotid-subclavian bypass, thromboendarterectomy of the abdominal aorta, and aorto-iliac bypass grafts. 3 years later she is greatly improved. This is the first report of Takayasu's arteritis from Ethiopia. International studies on the disease are summarized.
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PMID:Takayasu's disease in an Ethiopian. 198 1

The aim of this study was to compare, both subjectively and objectively, four modern rate-responsive pacing modes in a double-blind crossover design. Twenty-two patients, aged 18 to 81 years, had an activity-sensing dual chamber universal rate-responsive (DDDR) pacemaker implanted for treatment of high grade atrioventricular block and chronotropic incompetence. They were randomly programmed to VVIR (ventricular demand rate-responsive), DDIR (dual chamber demand rate-responsive), DDD (dual chamber universal) or DDDR (dual chamber universal rate-responsive) mode and assessed after 4 weeks of out-of-hospital activity. Five patients, all with VVIR pacing, requested early reprogramming. The DDDR mode was preferred by 59% of patients; the VVIR mode was the least acceptable mode in 73%. Perceived "general well-being," exercise capacity, functional status and symptoms were significantly worse in the VVIR than in dual rate-responsive modes. Exercise treadmill time was longer in DDDR mode (p less than 0.01), but similar in all other modes. During standardized daily activities, heart rate in VVIR and DDIR modes underresponded to mental stress. All rate-augmented modes overresponded to staircase descent, whereas the DDD mode significantly underresponded to staircase ascent. Echocardiography revealed no difference in chamber dimensions, left ventricular fractional shortening or pulmonary artery pressure in any mode. Cardiac output was greater at rest in the dual modes than in the VVIR mode (p = 0.006) but was similar at 120 beats/min. Beat to beat variability of cardiac output was greatest in VVIR mode (p less than 0.0001), with DDIR showing greater variability than DDD or DDDR modes (p less than 0.05). Mitral regurgitation estimated by Doppler color flow imaging was similar in all modes, but tricuspid regurgitation was significantly greater in VVIR than in dual modes (p less than 0.03). Subjects who preferred the DDDR mode and those who found the VVIR mode least acceptable had significantly greater increases in stroke volume when paced in the DDD mode than in the ventricular-inhibited (VVI) mode at rest (22%) when compared with subjects who preferred other modes (2%, p = 0.03). No other objective variable was predictive of subjective benefit from any rate-responsive pacing mode. Thus, dual sensor rate-responsive pacing (DDDR) is superior objectively and subjectively to single sensor (VVIR, DDIR and DDD) pacing and subjective benefit from dual chamber rate-augmented pacing is predictable echocardiographically.
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PMID:A randomized double-blind crossover comparison of four rate-responsive pacing modes. 199 90

Mitral valve prolapse is found in 2-5% of the whole population and is thus the most common valvular anomaly. The vast majority of patients are asymptomatic and remain free of complications during the follow-up. The most important complications are severe mitral regurgitation, bacterial endocarditis, cerebral ischemic stroke and arrhythmias. The risk of these complications is increased in patients with a holosystolic murmur, enlarged left atrium and/or ventricle, and redundant, thickened mitral leaflets. The complication rate increases with age and is generally higher in males. The risk of complications is very low in patients with an isolated systolic click or silent prolapse. Prophylactic treatment for endocarditis is recommended for patients with a systolic murmur. For patients surviving ischemic stroke, aspirin is recommended. Where the left atrium is enlarged and rhythm disturbances are present, anticoagulation treatment is preferable. Rhythm disturbances should be treated only when symptomatic. In cases of severe mitral regurgitation surgery should be considered early, since reconstruction of the valve can be achieved in the majority of patients.
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PMID:[Mitral valve prolapse--clinical significance of a frequent diagnosis]. 204 27

In previous reports that evaluated pulsed Doppler transmitral filling, the sampling site has varied; we examined the effect of the sample volume location on Doppler measurements. Studied were 97 patients: 58 with normal echocardiograms, 20 with mitral regurgitation, and 19 with miscellaneous cardiac diseases. Transmitral filling was recorded at the mitral anulus and at the left atrial and left ventricular (LV) sides of the mitral tips. As the sample volume was moved from the mitral anulus to the LV side, the peak velocity and time-velocity integral of early diastole increased (40.6 +/- 13.8 versus 59.0 +/- 19.0 cm/sec, 5.26 +/- 1.65 versus 8.35 +/- 2.37 cm; p less than 0.001) as did those of late diastole (48.7 +/- 11.5 versus 57.5 +/- 17.0 cm/sec, 3.48 +/- 0.97 versus 4.59 +/- 1.39 cm; p less than 0.001). The late-to-early diastolic peak velocity and time-velocity integral ratios and the late-to-total diastolic time-velocity integral ratio decreased (1.33 +/- 0.51 versus 1.06 +/- 0.41, 0.71 +/- 0.24 versus 0.58 +/- 0.19, 0.40 +/- 0.09 versus 0.36 +/- 0.08; p less than 0.001). The dependency of these indices on the sampling site was in the same degree in all three groups. However, the peak filling rate normalized to mitral stroke volume (4.71 +/- 1.43 versus 4.63 +/- 1.32 l/sec; p = NS) was not influenced by the sample volume location; thus this parameter may be more reliable for assessing LV filling.
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PMID:Dependency of the pulsed Doppler-derived transmitral filling profile on the sampling site. 206 34


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