Excessive vasoconstriction in rheumatic mitral stenosis with modestly reduced ejection fraction

AbstractObjectives. The primary hypothesis examined was that underfilling due to inflow obstruction accounts for modestly depressed ejection performance in mitral stenosis, Having found little evidence to support this hypothesis, we sought to determine other factors that might differentiate patients with different levels of ejection performance.Methods. Ventricular load and performance were compared in two groups of patients before and immediately after successful balloon valvuloplasty that was not complicated by mitral regurgitation: those in whom prevalvuloplasty ejection fraction was ≥0.55 (group I, n = 10) and those in whom it was <0.55 (group II, n =11).Results. Before valvuloplasty, mitral valve area was less in group II (0.65 cm2) than in group I (0.84 cm2, p = 0.02), but end-diastolic pressure (12 vs. 12 mm Hg in group I), end-diastolic wall stress (46 vs. 44 kdynes/cm2in group I) and end-diastolic volume (152 vs. 150 ml in group I) were not less in group II, nor were these variables significantly reduced compared with those of a normal control group. In group II, end-systolic volume was larger (77 vs. 55 ml in group I, p = 0.001) and cardiac output was less (3.1 vs. 3.6 liters/min in group I, p = 0.03), possibly owing to higher systemic vascular resistance (2,438 vs. 1,921 dynes·s·cm−5in group I, p = 0.05) and end-systolic wall stress (273 vs. 226 kdynes/cm2in group I, p = 0.06), although mean arterial pressure in the two groups was similar (91 vs. 84 mm Hg in group I, p = 0.22). Group II patients also had higher values for pulmonary vascular resistance (712 vs. 269 dynes·s·cm−5in group I, p = 0.03) and mean pulmonary artery pressure (47 vs. 29 mm Hg in group I, p = 0.02) despite similar values for mean left atrial pressure (20 vs. 18 mm Hg in group I, p = 0.35). After valvuloplasty, mitral valve area increased by 2.5- and 3-fold, respeditely, in group I (to 2.1 cm2and group II (to 2.0 cm2). Modest increases in left ventricular end-diastolic pressure, end-diastolic stress and end-diastolic volume (+9%) after valvuloplasty were statistically significant only for group II. End-systolic wall stress did not decline in either group II (281 kdynes/cm2) or group I (230 kdynes/cm2), and ejection fraction failed to increase significantly (0.49 to 0.51 for group II and 0.62 to 0.61 for group I) after valvuloplasty. Contractile performance estimated with a preload-corrected ejection fraction-afterload relation was within or near normal limits in all 19 patients in whom it was assessed.Conclusions. Excessive vasoconstriction may account for the higher afterload, lower ejection performance and tower cardiac output observed in a subset of patients with mitral stenosis because contractile dysfunction could not be detected and left ventricular filling—which was not subnormal despite severe inflow obstruction—improved only modestly after valvuloplasty

Impact of initiating carvedilol before angiotensin-converting enzyme inhibitor therapy on cardiac function in newly diagnosed heart failure

ObjectivesThe purpose of this research was to evaluate the therapeutic value of initiating a beta-blocker before an angiotensin-converting enzyme inhibitor (ACEI) in the treatment of heart failure.BackgroundAlthough ACEI and carvedilol produce benefits in heart failure, whether the order of initiation of therapy determines the impact on left ventricular (LV) function and New York Heart Association functional class (NYHA FC) has not been determined.MethodsA single-center, prospective, randomized, open-label study was performed. We evaluated whether initiation of therapy with carvedilol either before (n = 38) or after (n = 40) perindopril therapy in newly diagnosed patients in NYHA FC II to III heart failure with idiopathic dilated cardiomyopathy, with the addition of the alternative agent after six months, determined subsequent changes in NYHA FC and LV function (echocardiography and radionuclide ventriculography). Study drugs were titrated to maximum tolerable doses.ResultsThere were no differences in baseline characteristics between the study groups. After 12 months 11 patients died (6 in the group where the ACEI was initiated). At 12 months the group receiving carvedilol as initial therapy achieved a higher tolerable dose of carvedilol (43 ± 17 mg vs. 33 ± 18 mg, p = 0.03); a lower dose of furosemide (p &lt; 0.05); and better improvements in symptoms (NYHA FC, p &lt; 0.002), LV ejection fraction (radionuclide: 15 ± 16% vs. 6 ± 13%, p &lt; 0.05; echocardiographic, p &lt; 0.01), and plasma N-terminal pro-brain natriuretic peptide concentrations (p &lt; 0.02).ConclusionsAs opposed to the conventional sequence of drug use in the treatment of heart failure, initiation of therapy with carvedilol before an ACEI results in higher tolerable doses of carvedilol and better improvements in FC and LV function

Effect of abrupt mitral regurgitation after balloon valvuloplasty on myocardial load and performance

AbstractThe concept that mitral regurgitation masks myocardial dysfunction by reducing afterload and augmenting ejection performance has not been well established in humans. The effect of abruptly produced mitral regurgitation on left ventricular loading and performance was therefore evaluated in five patients who developed this complication after an otherwise successful percutaneous balloon mitral valvuloplasty. Mitral valve area by Gorlin formula calculated with forward flow increased from 0.92 ± 0.14 to 2.75 ± 0.82 cm2. Mean left atrial pressure did not decrease (19 ± 4 to 19 ± 6 mm Hg). The size of the left atrial Vwave relative to mean left atrial pressure (peak V— mean left atrial pressure) increased from 7 ± 4 to 19 ± 6 mm Hg. Angiographic mitral regurgitation increased from 0+ or 1 + to >3+ in each patient and regurgitant fraction increased from 0.23 ± 0.11 to 0.55 ± 0.99 (p < 0.01).End-diastolic volume increased modestly from 148 ± 15 to 159 ± 15 ml (p = NS). Heart rate increased from 54 ± 5 to 71 ± 8 heats/min (p < 0.05), which may have prevented further increases in preload by shortening the filling period. End-systolic stress decreased by 32% from 277 ± 34 to 188 ± 52 kdyn/cm2(p < 0.01) as a result of a 25% decrease in end-systolic pressure from 121 ± 8 to 91 ± 7 mm Hg and a 16% decrease in end-systolic volume from 67 ± 13 to 56 ± 8 ml (p = NS). Contractility estimated from the preload-corrected ejection fraction-afterload relation decreased in one of the five patients and did not increase in the others despite an increase in heart rate, possibly as a result of myocardial depression from the balloon procedure itself. Nevertheless, the decrease in end-systolic volume could not be attributed to a net increase in contractility. The result of the changes in loading was an increase in ejection fraction from 0.55 ± 0.05 to 0.65 ± 0.04 (p < 0.05).Thus, abruptly produced mitral regurgitation increases ejection performance by reducing afterload without increasing contractility. This should be taken into consideration when anticipating the results of valve replacement for acute or subacute mitral regurgitation

Prevention of infective endocarditis associated with dental interventions : South African Heart association position statement, endorsed by the South African Dental Association

CITATION: Jankelow, D., et al. 2017. Prevention of infective endocarditis associated with dental interventions : South African Heart association position statement, endorsed by the South African Dental Association. SA Heart, 14(3):170-174, doi:10.24170/14-3-2716.The original publication is available at http://www.journals.ac.za/index.php/SAHJENGLISH ABSTRACT: Infective endocarditis (IE) is associated with significant morbidity and mortality. Prevention is therefore an important clinical entity. The maintenance of optimal oral health is likely to play the most important role in protecting those at risk for IE. Both patients and health care practitioners must be educated in this regard. Guidelines have recommended that antibiotic prophylaxis should be limited to individuals (undergoing certain high-risk dental procedures) with underlying cardiac conditions that are associated with the greatest risk of an adverse outcome from IE. These conditions include prosthetic valves, congenital heart disease and previous IE. In South Africa, and other developing countries, IE is often a disease of young patients with rheumatic heart disease (RHD) and carries a very poor prognosis. In contrast, IE in Europe/North America, where guidelines and indications for antibiotic prophylaxis have been reduced, has a different spectrum of factors. These patients are older with degenerative valve disease. IE may also occur as a result of invasive health care associated procedures or in the setting of prosthetic valves and implantable cardiac devices. Recently published international guidelines cannot be automatically applied to countries where RHD is common and oral hygiene is poor. We therefore recommend that patients with RHD should also receive antibiotic prophylaxis prior to the listed dental procedures. Antibiotic prophylaxis should be prescribed after stressing the role of good oral health and why the approach differs in South Africa. There should be close cooperation between the dental practitioner and clinician as to who should receive prophylaxis and who should not.http://www.journals.ac.za/index.php/SAHJ/article/view/2716Publisher's versio