Barbara Berko

Antianginal effects of intravenous nitroglycerin over 24 hours.

To determine the constancy of hemodynamic and antianginal effects of the constant infusion of intravenous nitroglycerin (NTG) and their relationship to infusion rate and plasma NTG concentration, we administered maximal tolerated doses of intravenous NTG (range 10 to 120 micrograms/min, mean = 52 +/- 33 micrograms/min) and placebo to 10 patients with chronic stable angina for 25 hr each in a randomized, double-blind fashion. Sublingual NTG (0.4 mg) was given at 24.5 hr of infusion as a positive control. Bicycle exercise time (NIH protocol), blood pressure, heart rate, exercise ST response, and venous plasma NTG were determined before and at 1, 4, 8, 24, and 24.5 hr. Plasma NTG was linearly related to infusion rate, reached a steady state within 15 min and was unchanged over 24 hr (mean = 5.5 +/- 1.2 ng/ml). Mean plasma NTG clearance was 9.3 liters/min. However, during dose titration, patients demonstrated different relationships between plasma NTG and hemodynamic effects, with widely varying slopes and intercepts. Intravenous NTG produced a sustained reduction in blood pressure and a rise in heart rate at rest, and a reduction in blood pressure during submaximal exercise at as late as 24 hr, associated with reduced submaximal ST segment abnormality. In contrast, exercise tolerance to onset of angina showed a marked initial increase on intravenous NTG but fell progressively and did not differ from that with placebo at 24 hr. Increased exercise tolerance was associated with an increase in maximal heart rate and double product (heart rate X blood pressure), suggesting that direct coronary vasodilation and/or reduced left ventricular volume were the principal determinants of increased exercise tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Alterations in diastolic function in response to progressive left ventricular hypertrophy

To examine the time course of the functional consequences of progressive left ventricular hypertrophy, diastolic left ventricular inflow and wall thinning variables were analyzed in 13 dogs before and 2, 4, 8 and 12 weeks after creation of perinephritic hypertension. Left ventricular echocardiograms were digitized for dimensions, mass and peak rates of wall thinning (-dh/dt/h) and cavity enlargement (dD/dt/D). Doppler recordings of left ventricular inflow were analyzed for peak early (E) and late (A) diastolic inflow velocities, their ratio and atrial filling fraction. At 2 weeks, systolic blood pressure increased from 151 to 233 mm Hg, wall stress from 52 to 80 kdynes/cm2 and posterior wall thickness from 0.68 to 0.84 cm (all p less than 0.05). Left ventricular mass increased from 90 to 115 g over 12 weeks (p less than 0.05). Heart rate, cavity size and systolic shortening were unchanged at all data points. Diastolic abnormalities accompanied the developing hypertrophy and included impairment of early function, as demonstrated by a peak rate of wall thinning, from -13.4 to -8.9 l/s at 2 weeks (p less than 0.05), increased dependence on atrial systolic filling, a decrease in E/A from 1.68 to 1.29 at 4 weeks (p less than 0.05) and an increase in atrial filling fraction from 30% to 43% at 8 weeks (p = NS). Thus, diastolic dysfunction is an early consequence of experimental left ventricular hypertrophy. Different aspects of diastolic impairment are sensitively reflected by echocardiographic Doppler recordings, suggesting that these methods should be useful for the detection of diastolic dysfunction in human patients.

Echocardiographic visualization of coronary artery anatomy in the adult

In the light of technologic advances and the development of new imaging planes, the feasibility of two-dimensional echocardiographic visualization of coronary artery anatomy was reevaluated in the adult. Thirty-five subjects were studied using an ultrasonograph equipped with a 3.5 and 5.0 MHz annular array transducer, digital processing and cine loop review. There were 18 normal subjects and 17 patients with heart disease, including 9 patients with valvular, 5 patients with coronary, 2 patients with congenital and 1 patient with cardiomyopathic disease. The mean age was 47 +/- 18 years (range 17 to 79). Modifications of standard parasternal and apical views permitted high quality images of portions of each of the major epicardial vessels adequate for assessment of luminal diameter. The left main coronary artery was seen in 30 (86%) of the 35 subjects and its bifurcation was seen in 15. The left anterior descending coronary artery was seen in 30 subjects (mean length 3.9 +/- 2.3 cm, maximal length 7.5), the left circumflex artery in 11 (1.1 +/- 1.0, maximal 3.0) and the right coronary artery in 32 (5.6 +/- 2.6, maximal 12). Proximal and mid portions of the left anterior descending artery were seen in 23 and 11 subjects, respectively. The average proximal length visualized was 4.2 cm, and the average luminal diameter visualized was 4.9 mm. The average length of the mid left anterior descending coronary artery seen was 1.9 cm and the average luminal diameter seen was 4.6 mm. The proximal right coronary artery was seen in 17 subjects (average visualized length 2.7 cm and average diameter 3.1 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Disparity between ejection and end-systolic indexes of left ventricular contractility in mitral regurgitation.

To examine left ventricular function in mitral regurgitation (MR), we compared the ejection phase indexes of left ventricular contractility with maximal systolic elastance (Emax) in an experimental preparation of MR. In eight anesthetized open-chest dogs, pressure-volume loops were derived during afterload manipulation with methoxamine and nitroprusside from simultaneous left ventricular pressure and dimensional (sonomicrometry techniques) data before and after creation of MR. From these data maximal systolic elastance (Emax), the end-systolic pressure-volume relationship (ESPVR), and the end-systolic stress-volume relationship (ESSVR) were determined by linear regression analysis. After creation of MR, end-diastolic volume increased significantly (40 +/- 13 to 53 +/- 18 ml, p less than .001); likewise end-systolic volume increased (28 +/- 11 to 33 +/- 15 ml, p less than .05). Ejection fraction increased after MR (35 +/- 6% to 44 +/- 8%, p less than .005), as did the mean velocity of fiber shortening (0.62 +/- 0.20 to 1.02 +/- 0.39 sec-1, p less than .02). In contrast, Emax declined significantly (4.63 +/- 2.5 to 3.54 +/- 1.94 mm Hg/ml, p less than .05); ESPVR and ESSVR showed similar directional changes. An inverse relationship was found between systolic elastance and end-diastolic volume in both control and MR states. When Emax, ESPVR, and ESSVR were normalized to end-diastolic volume, they were unchanged after MR. These results suggest that either there was a decline in left ventricular contractile state after MR, or that contractility was unchanged (if elastance is normalized for increased contractility, but occurred as a consequence of increased preload with no significant change in afterload.

Valvular Heart Disease in Osteogenesis Imperfecta: Presentation of a Case and Review of the Literature

Osteogenesis imperfecta (OI) is a rare inheritable disorder of connective tissue. While musculoskeletal abnormalities are well known, cardiovascular involvement is rare. Aortic root dilation is the most common cardiovascular manifestation. OI preferentially affects the left‐sided heart valves, for unclear reasons, leading to aortic and mitral regurgitation. Valve replacement surgery carries a unique set of issues in this population, and fewer than 40 cases have been reported. We report a case of chronic severe aortic regurgitation in a patient with OI complicated by the development of a flail aortic valve leaflet and presenting with a transient ischemic attack. The patient subsequently underwent successful combined bioprosthetic aortic valve replacement and coronary artery bypass grafting. We review the literature on valvular disease and other cardiovascular manifestations in OI and the related surgical considerations relevant to this patient population. (Echocardiography 2010;27:69‐73)

Recognition of cardiac tamponade in the presence of severe pulmonary hypertension

Excerpt The clinical features of cardiac tamponade in a patient with a pericardial effusion may include dyspnea, elevated systemic venous pressure, and pulsus paradoxus. Right ventricular diastolic...

Origin of the third heart sound: comparison of ventricular wall dynamics in hyperdynamic and hypodynamic types.

To investigate the left ventricular wall dynamics conducive to the third heart sound (S3) in both hyper- and hypodynamic filling conditions, eight dogs were studied in which an S3 was produced by hypoxemia and in eight others by acute mitral regurgitation. Pulse transit sonomicrometry crystals were used to measure external left ventricular dimension dynamics in the two principal axes. A miniature accelerometer was used to detect the epicardial S3 vibration. The development of the S3 was invariably associated with an increased peak velocity of long-axis external dimensional expansion in early diastole. This enhanced long-axis filling activity was not dependent on increased global chamber or short-axis filling dynamics and sometimes occurred when global filling rate was unchanged. In addition, the short-axis filling rate was sometimes reduced as the S3 developed. It is concluded that the common denominator of S3 generation in this acute dog model is exaggerated long-axis diastolic expansion activity which is present in both hyper- and hypodynamic left ventricular filling.

Radiation-induced cardiovascular dysfunction.

Coronary artery disease and valvular dysfunction are long-term complications of mediastinal irradiation. We describe 3 patients who underwent successful combined coronary artery bypass grafting and valve replacement for symptoms related to radiation-induced coronary artery and valvular disease.

Variable responses of mitral valve motion and flow in systemic hypertension and in idiopathic dilated cardiomyopathy

The relation between transmitral flow and diastolic mitral valve motion were examined in 17 normal persons, 14 patients with hypertension and 12 patients with idiopathic dilated cardiomyopathy. M-mode echograms were analyzed for early and late diastolic mitral leaflet separations, their ratio and E-F slope. Pulsed Doppler transmitral flow was analyzed for early and late velocities, their ratio and early flow deceleration. Early diastolic mitral valve leaflet separation was reduced in patients with hypertension (at 28 +/- 5 mm [p less than 0.05] ) and in patients with cardiomyopathy (at 22 +/- 3 mm [p less than 0.01] ). Flow velocity was also reduced in patients with hypertension (at 52 +/- 11 cm/s [p less than 0.05] ) and in patients with cardiomyopathy (at 48 +/- 15 cm/s [p less than 0.01] ). However, early leaflet separation and flow velocity were not related (r = 0.26). Late diastolic leaflet separation was similar (at 25 +/- 5 mm) in normal subjects and in those with hypertension (at 23 +/- 6 mm), but was reduced in patients with cardiomyopathy (at 18 +/- 3 mm [p less than 0.01] ). In contrast, late flow velocity was increased in patients with hypertension (at 52 +/- 12 cm/s [p less than 0.05] ) but unchanged in patients with cardiomyopathy (at 42 +/- 16 cm/s). The ratio of early to late leaflet separation was similar in all groups, whereas the ratio of flow velocities was reduced in hypertensive patients. Neither the E-F slope not early flow deceleration was altered in either pathologic group. Thus, hypertension and cardiomyopathy had similar effects in early rather than late diastole.(ABSTRACT TRUNCATED AT 250 WORDS)