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PubMed1993

Noninvasive evaluation of right ventricular and pulmonary artery systolic pressures in patients with ventricular septal defects: simultaneous study of Doppler and catheterization data.

The method for evaluating right ventricular and pulmonary artery systolic pressures by subtracting the systolic pressure gradient across the ventricular septal defect from the cuff systolic blood pressure is documented. To confirm the reliability and accuracy of this method, simultaneous continuous wave Doppler echocardiography and left and right cardiac catheterization were performed in 66 patients with congenital ventricular septal defects. The comparisons between the Doppler-derived right ventricular or pulmonary artery systolic pressures and those measured by catheterization yielded an excellent correlation (r = 0.969, y = 1.035x - 3.627, SEE = 8.2 mm Hg, p < 0.001 and r = 0.972, y = 1.012x - 2.904, SEE = 7.6 mm Hg, p < 0.001), respectively. There was a close agreement between the Doppler-derived right ventricular or pulmonary artery systolic pressures and those measured by catheters, and the differences between the two measurements did not differ significantly from zero. It is concluded that Doppler echocardiography offers a reliable and accurate method for noninvasive assessment of right ventricular and pulmonary artery systolic pressures in patients with ventricular septal defects.

Adolescent↗
PubMed1994

Effect of altered contractility on the linearity of regional left ventricular end-systolic relations in intact hearts.

The purpose of these studies was to determine the effect of altered regional contractility on the linearity of regional left ventricular end-systolic relations. Significant change in the shape of these relations would limit their application as load-independent indices of regional contractility. In a paced, open-chest pig heart preparation (n = 7), the left ventricular end-systolic pressure-segment length relation (ESPLR) and pressure-wall thickness relation (ESPTR) were obtained over a wide range of end-systolic pressures (134 +/- 9 to 70 +/- 6 mm Hg). Regional inotropic state was varied with intracoronary calcium and verapamil. The shapes of the ESPLR and ESPTR were characterized by using linear and quadratic models. Both provided a good fit, although the quadratic model showed a slight concavity to the segment length and thickness axes (second-order coefficient < 0). In the linear model, calcium increased the slope of the ESPLR by 111% (p < 0.01) and the slope of the ESPTR by 170% (p < 0.01). At a pressure of 100 mm Hg, end-systolic segment length (L100) shifted to the left (p < 0.05) and end-systolic wall thickness (T100) to the right (p < 0.025). Verapamil decreased the slope of the ESPLR by 45% (p < 0.01) and of the ESPTR by 33% (p not significant) and produced significant shifts in L100 (p < 0.001) and T100 (p < 0.025). The values of L100 and T100 determined by the quadratic fit were nearly identical to those for the linear fit, and both showed similar significant shifts with altered contractility. There was no significant change in the shape of the quadratic fit (as assessed by the second-order coefficient) with different contractile states. It is concluded that the curvilinearity of the ESPLR and ESPTR under physiologic conditions is slight and appears to be independent of the contractile state. Furthermore, a linear model of regional end-systolic relations can be used to assess regional left ventricular function in intact hearts.

Animals↗
PubMed1979

Systolic hypertension: hemodynamic mechanism and choice of antihypertensive treatment.

Arterial compliance and indexes of ventricular ejection were measured in 27 men with systolic hypertension. The patients were separated into two age groups, younger or older than age 35 years, and matched with normotensive control subjects. Arterial compliance was estimated from analysis of the monoexponential blood pressure-time curve during diastole, according to a simple viscoelastic model. In the younger patients, arterial compliance and stroke volume were within normal ranges. Rapid ejection time was significantly reduced (P less than 0.001), indicating an increased venlocity in the first part of ventricular ejection. Systolic pressure decreased significantly after administration of propranolol, which also caused prolongation of rapid ejection time. In the older patients, indexes of ventricular ejection were within normal limits. arterial compliance was significantly reduced (P less than 0.01) and was negatively correlated with the level of systolic pressure (P less than 0.001). Systolic pressure decreased significantly after administration of sodium nitroprusside, which caused an increase in arterial compliance. These findings provide evidence that: (1) the hemodynamic mechanisms of systolic hypertension differ in younger and older patients, and (2) these hemodynamic differences should be taken into account when choosing drugs to decrease systolic pressure.

Adult↗
PubMed1983

Effects of enhanced afterload (methoxamine) and contractile state (dobutamine) on the left ventricular late-systolic wall stress-dimension relation.

Although the left ventricular (LV) end-systolic pressure-dimension relation is a load-independent, sensitive index of contractile state, its accurate determination requires afterload manipulation. The slope value of the late-systolic stress-dimension relation determined under resting conditions has been suggested as an alternative index of contractility that can be assessed without pharmacologic intervention. To evaluate this relation, 14 normal subjects were studied by M-mode echocardiography, phonocardiography and indirect carotid pulse tracings during infusion of methoxamine to increase afterload. Seven of these subjects were also studied after infusion of dobutamine to increase contractility. Continuous systolic stress-dimension trajectories were computer generated from digitized tracings. The late-systolic portions of these curves were found to be linear and the slope and intercept were determined. The slope value was sensitive to both afterload and contractility, and the magnitude of change in slope value was relatively greater during afterload enhancement than during inotropic stimulation. A strong correlation of slope value with peak systolic stress was found. Thus, the late-systolic stress-dimension relation is linear with a slope value which is dependent on both LV contractility and afterload. Like other ejection phase indexes, the usefulness of this index is limited by its inability to distinguish changes in contractile state from alterations in loading conditions.

Adolescent↗
PubMed1985

Effects of training on systolic time intervals at rest and during isometric exercise in men and women 61 to 64 years old.

To determine whether regular exercise improves left ventricular (LV) contractile function in persons 60 years and older, systolic time intervals (STIs) were measured in 10 healthy men and women (mean age 62 +/- 1 year [+/- standard deviation]) before and after 6 months of intense endurance training. STIs, systolic and diastolic blood pressure (BP) and heart rate (HR) were determined at rest and in response to isometric handgrip exercise. Systolic BP, diastolic BP and HR increased acutely from rest in response to handgrip (p less than 0.002). The indexes of total electromechanical systole and LV ejection time (ET) index increased (p less than 0.01), preejection period (PEP) index increased (p less than 0.05) or remained unchanged and PEP/LVET did not change from values at rest in response to handgrip. Training resulted in an 18% increase in maximal oxygen uptake (p less than 0.01). After training, systolic and diastolic BP were reduced at rest (p less than 0.002) and, along with HR, were lower in response to handgrip (p less than 0.002). However, training did not alter STIs at rest or during handgrip. These findings indicate that healthy persons in their 60s have a normal LV response to isometric exercise. Prolonged, intense endurance training does not alter LV contractile function at rest or in response to isometric exercise. However, training can significantly reduce BP at rest, and markedly lower the HR-systolic BP product attained during acute isometric stress, even in normotensive older subjects.

Aged↗
PubMed1985

Intact systolic left ventricular function in clinical congestive heart failure.

Clinical congestive heart failure (CHF) is traditionally associated wtih significant left ventricular (LV) systolic dysfunction. Over a 1-year period, 58 patients with CHF and intact systolic function (LV ejection fraction [EF] 62 +/- 11%) were identified. An objective clinical-radiographic CHF score was used to document the clinical impression. Based on radionuclide evaluation of peak filling rate, 38% of these patients were found to have a significant abnormality in diastolic function as measured by peak filling rate (less than 2.50 end-diastolic volume/s). An additional 24% of the patients had probable diastolic dysfunction with borderline abnormal peak filling rate measurements (2.5 to 3.0 end-diastolic volume/s). The disease states most frequently associated with CHF and intact systolic function were coronary artery disease and systemic hypertension. During a 3-month sampling period 42% of patients with clinical diagnosis of CHF referred to the nuclear cardiology laboratory were found to have intact systolic function; thus, intact systolic function is not uncommon in patients with clinical CHF. Abnormal diastolic function is the most frequently encountered mechanism for the occurrence of CHF. Definition of systolic and diastolic function appears relevant for development of optimal therapeutic strategies for the treatment of patients with CHF.

Adult↗
PubMed1986

Relation between left ventricular functional reserve during exercise and resting systolic loading conditions in chronic aortic regurgitation.

The relation between systolic loading conditions at rest and left ventricular (LV) functional response to exercise was assessed in 31 patients with aortic regurgitation (AR) (20 asymptomatic, 11 symptomatic) and 10 control subjects. Peak and end-systolic wall stress determined from echocardiography and cuff systolic pressure at rest were used as indirect measures of LV systolic loading and were compared with LV ejection fraction response to handgrip and bicycle exercise by radionuclide ventriculography. Both peak and end-systolic wall stress were significantly higher in both asymptomatic (164 +/- 33 and 90 +/- 25 X 10(3) dynes/cm2) and symptomatic (196 +/- 33 and 134 +/- 17 X 10(3) dynes/cm2) patients with AR than in the control subjects (125 +/- 22 and 61 +/- 14 X 10(3) dynes/cm2 p less than 0.01), and correlated inversely with the changes in LV ejection fraction during handgrip (r = -0.63 and r = -0.73) and bicycle (r = -0.68 and r = 0.87) exercise. In patients with AR, resting systolic loading conditions closely reflect LV functional reserve during exercise.

Adult↗
PubMed1987

Differential effects of milrinone and dobutamine on right ventricular preload, afterload and systolic performance in congestive heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

To compare the effects of intravenous dobutamine and milrinone on right ventricular (RV) systolic function, 14 patients with severe congestive heart failure underwent simultaneous radionuclide-hemodynamic study. Patients were randomized to receive intravenous milrinone (50 micrograms/kg bolus then 0.5 microgram/kg/min) or dobutamine (2.5 to 15 micrograms/kg/min) to achieve equal increases in cardiac output. Both drugs significantly improved cardiac performance, with identical 24% increases in mean cardiac index (p less than 0.05 vs baseline; difference not significant for milrinone vs dobutamine) and no change in heart rate. Neither drug substantially altered RV preload, as reflected by mean right atrial pressure and RV end-diastolic volume. Both drugs caused similar increases in RV ejection fraction (mean +/- standard deviation; dobutamine: 0.32 +/- 0.09 to 0.40 +/- 0.11; p less than 0.05; milrinone: 0.35 +/- 0.19 to 0.43 +/- 0.21; p less than 0.05) resulting from reductions in RV end-systolic volume. RV afterload reduction contributed substantially to drug effect on RV systolic performance in patients treated with milrinone but not those treated with dobutamine. With doses effecting equal increases in cardiac index and RV systolic performance, pulmonary artery end-systolic pressure was significantly reduced by milrinone (40 +/- 12 to 33 +/- 12 mm Hg; p less than 0.05), but not by dobutamine. Thus, in patients with congestive heart failure milrinone's effect on RV systolic function is explainable, at least in part, by RV afterload reduction, whereas RV inotropic augmentation contributed more strongly to dobutamine's effect.

Adult↗
PubMed1991

Trends in systolic blood pressure, 24-hour sodium excretion, and stroke mortality in the elderly in Belgium.

Data from six surveys of systolic blood pressure conducted in Belgium between 1967 and 1986 were analyzed. The mean ages of the six groups of 3,328 subjects ranged from 70 to 81 years. The prevalence of systolic blood pressure levels above 159 mm Hg decreased between 1967 and 1986 from 51% to 21% in men and 66% to 22% in women; severe hypertension (systolic blood pressure greater than 220 mm Hg) nearly disappeared. During the same period, body mass index increased 1.1 kg/m2 in men and was unchanged in women; mean systolic blood pressure decreased from 159 to 142 mm Hg in men and from 171 to 147 mm Hg in women; the proportion of subjects receiving treatment for hypertension increased from 10% to 36% in men and from 18% to 41% in women; and the mean standardized 24-hour sodium excretion decreased from 265 to 188 mmol in men and from 208 to 160 mmol in women. Systolic blood pressure levels were significantly and independently related to sodium excretion in the 1967 and 1972 studies. The decrease in systolic blood pressure in Belgium was influenced by the combined effects of more and better treatment for hypertension and a decrease in sodium intake.

Adult↗
PubMed1996

Repair of coarctation of the aorta in adults: the fate of systolic hypertension.

BACKGROUND: The benefit of coarctation repair in adults has been questioned by suggesting that hypertension may not be relieved by the operation and that surgical intervention may have no impact on the natural history of the disease. METHODS: To delineate the impact of surgical intervention on systolic hypertension, we conducted a retrospective review of 26 adults with a mean age of 32 +/- 10 years who underwent coarctation repair between 1987 and 1993. All patients were hypertensive (mean systolic blood pressure, 174 +/- 21 mm Hg; range, 140 to 220 mm Hg), and 18 patients (69%) were on a regimen of at least one hypertensive medication at the time of surgical admission. All patients underwent catheterization, and the mean peak systolic gradient across the coarctation was 61 +/- 25 mm Hg (range, 25 to 120 mm Hg). Operation included resection and end-to-end anastomosis (3 patients), resection with an interposition tube graft (6 patients), a bypass graft (11 patients), and patch angioplasty (6 patients). There was no hospital mortality or late morbidity. RESULTS: Intermediate follow-up was available at a mean of 2.3 +/- 2 years (range, 1 to 7 years). At last follow-up, the peak systolic gradient between the upper and lower body was trivial (< or = 10 mm Hg) in 23 patients (88%) and mild (11 to 20 mm Hg) in 3 (12%). All patients had significant improvement in systolic blood pressure (p < 0.001) compared to preoperative values, and the majority (23, 88%) were normotensive. More than half of the patients (14, 54%) were still on a regimen of antihypertensive medication at last follow-up, with a trend (p = 0.06) toward older patients requiring medication. CONCLUSIONS: Surgical repair of coarctation in adults is an effective, low-risk procedure, which results in a significant improvement in systolic hypertension and a decreased requirement of antihypertensive medications.

Adult↗
PubMed1992

Epidemiology of isolated systolic hypertension in Pu-Li, Taiwan.

The clinical significance of isolated systolic hypertension (systolic blood pressure greater than or equal to 160 mmHg and diastolic blood pressure less than 90 mmHg) has long been recognized, but its prevalence and correlates have not been well characterized. A community-based study was carried out by the Yang-Ming Crusade in 1987-1988 in Pu-Li Town, Taiwan. Of the 2573 registered residents over 30 years old, 1738 were interviewed, and their fasting blood samples were drawn and tested. The prevalence of isolated systolic hypertension was 2.1%. Age-specific prevalence increased with age. No significant difference was found between men and women. No trend was found at the urbanizational level. To study the significant correlates of isolated systolic hypertension, univariate analyses were applied first. Stratified analyses by age and by sex were used for interaction assessment. Based on the above findings as well as from the clinical point of view, logistic regression was used for multivariate analyses. Logistic regression analysis showed that after controlling the covariates simultaneously, four variables were significantly correlated with isolated systolic hypertension: age (greater than or equal to 50 vs. less than 50 years, OR = 3.4, 95% CI = 1.6-7.2); diabetes (yes vs. no, OR = 2.4, 95% CI = 1.2-4.7); blood urea nitrogen (greater than or equal to 25 vs. less than 25 mg/dl, OR = 2.1, 95% CI = 1.2-3.9); and physical activity (frequent vs. infrequent, OR = 1.8, 95% CI = 1.0-3.1). In comparison with definite (greater than or equal than 160/95 mmHg) and borderline (140/90-160/95 mmHg) hypertension as defined by WHO, the different sets of predictors and the possible adverse effect of frequent physical activity on isolated systolic hypertension were found and discussed.

Adult↗
PubMed1993

Assessment of regional myocardial performance with end-systolic pressure length and thickness relationships.

Although end-systolic pressure length and thickness relationships (ESPLR, ESPTR) are now widely used as substitutes for the end-systolic pressure volume relationships, there are some reservations about their use as an index of left ventricular (LV) performance. This study addressed three issues, namely: (1) which loading technique (decreasing preload by inferior vena cava (IVC) balloon occlusion or increasing systolic pressure by aortic constriction) is the most likely to yield usable data; (2) reproducibility of these relationships over a 30 min period; and (3) whether by using end-ejection (zero aortic flow) as a definition of end-systole, ESPLR and ESPTR can be used to characterize myocardial performance independent of load. Thirteen anesthetized beagles, weighing 16-25 kg, were used for this study, and were instrumented with sonomicrometers. We found that when ESPLR and ESPTR were constructed from data derived during aortic constriction, the slopes of these relationships were steeper and more curvilinear than when they were constructed from data recorded during IVC occlusion. In addition, the mean between ESPLR, ESPTR obtained 30 min apart was small, although there was a fair degree of variability between the first and second measurements. Using end-ejection to define end-systole, both ESPLR and ESPTR were relatively insensitive to loading conditions (LV end-diastolic pressure of 8-12 mmHg and 14-18 mmHg, aortic systolic pressure of 7-10 mmHg and 20-25 mmHg above baseline (in terms of the slope and shift (leftward or rightward) in these relationships, but were sensitive to inotropic interventions (dobutamine 2.5 micrograms/kg per min and 5 micrograms/kg per min). We conclude that, ESPLR and ESPTR, defined from measurements at end-ejection, can be used as adequate descriptors of regional myocardial performance if they were constructed from data over a similar pressure range during IVC balloon occlusion.

Animals↗
PubMed1993

Abnormal systolic blood pressure response during exercise recovery in patients with angina pectoris.

OBJECTIVES: This study was conducted to clarify the mechanisms of the abnormal systolic blood pressure response after exercise in patients with angina pectoris. BACKGROUND: An abnormal systolic blood pressure response in patients with angina pectoris has been observed not only during exercise but also during the recovery period after exercise. However, the mechanisms of this abnormal response during recovery have not been elucidated. METHODS: Thirty-five patients with angina pectoris and 17 control subjects underwent bicycle ergometric studies after insertion of a Swan-Ganz catheter. RESULTS: In control subjects, all hemodynamic variables decreased rapidly after exercise. In 7 of the 35 patients, systolic blood pressure increased after exercise. The patients with angina were classified into two groups. In group I (17 patients), changes in systolic blood pressure during recovery were smaller than those in control subjects. In group II (18 patients) recovery of systolic blood pressure was normal. Changes in stroke index from rest to peak exercise were smaller in group I than in group II. Stroke index in both patient groups increased paradoxically during recovery. The increase in systemic vascular resistance index during recovery and the ratio of plasma norepinephrine concentration to cumulative work load were greater in group I than in group II. CONCLUSIONS: An abnormal systolic blood pressure response after physical exercise in patients with angina pectoris is indicative of severe myocardial ischemia during exercise and may be caused by an increase in stroke volume due to recovery from myocardial ischemia and increased systemic vascular resistance secondary to exaggerated sympathetic nervous activity.

Adult↗
PubMed2005

Can pro-brain natriuretic peptide be used as a noninvasive predictor of elevated left ventricular diastolic pressures in patients with normal systolic function?

OBJECTIVES: This study was sought to investigate whether plasma N-terminal pro-brain natriuretic peptide (proBNP) can help identify patients with an elevated left ventricular end-diastolic pressure (LVEDP) or filling pressures in patients with a normal systolic function. BACKGROUND: The proBNP is a good predictor of an elevated LVEDP in patients with a systolic dysfunction. However, whether proBNP can predict an elevated LVEDP in patients with a normal systolic function remains to be determined. METHODS: The LV pressures were measured by fluid-filled catheters in 216 patients (125 men, mean age 60 +/- 10 years) with a normal systolic function (ejection fraction 66% +/- 8%, range 50%-81%) who were undergoing diagnostic cardiac catheterization. The proBNP was sampled at the time of cardiac catheterization and was measured using a quantitative electrochemiluminescence immunoassay. RESULTS: The log-transformed proBNP levels correlated significantly with the LVEDP (r = 0.33, P = .001) and LV pre-A-wave pressure (pre-A pressure) (r = 0.31, P = .001). An elevated proBNP, defined as >315 pg/mL, predicted an LVEDP > or = 15 mm Hg with a sensitivity of 16% and a specificity of 95% as well as a pre-A pressure > or = 15 mm Hg with a sensitivity of 36% and a specificity of 95%. However, among the 93 patients with an LVEDP > or = 15 mm Hg, 77 (83%) patients had a normal proBNP concentration (< 315 pg/mL). CONCLUSION: The proBNP level showed weak correlations with the LVEDP and LV pre-A pressure in patients with a normal systolic function. Although high proBNP levels can predict an elevated LV diastolic pressure with high specificity, the sensitivity was quite low. Because the majority of patients with an elevated LVEDP had a normal proBNP, the proBNP level may not be suitable as a screening test for assessing LV filling pressures in the presence of normal systolic function.

Adult↗
PubMed2006

Relation of right ventricular peak systolic pressure to major adverse events in patients undergoing cardiac resynchronization therapy.

The degree to which increased right-sided heart pressures influence outcome in cardiac resynchronization therapy (CRT) is unclear. High right ventricular (RV) pressures may contribute to septal malpositioning, thus hindering effective resynchronization. We hypothesized that patients with high RV systolic pressures before CRT implantation would have poorer outcome. We evaluated echocardiograms, electrocardiograms, and clinical records from 75 consecutive patients with CRT. RV systolic pressure was calculated from the peak tricuspid regurgitant, time-velocity profile. The primary end point was a composite of mortality, cardiac transplantation, or need for a left ventricular assist device. Events were evaluated by Kaplan-Meier curves and Cox proportional hazard ratios. Patients grouped by RV systolic pressure divided at the median of 35 mm Hg were similar except for more renal insufficiency and RV dysfunction when RV systolic pressure was >35 mm Hg. Univariate analysis identified RV systolic pressure >35 mm Hg (hazard ratio [HR] 3.32), diabetes (HR 2.45), renal insufficiency (HR 3.52), atrial fibrillation (HR 3.07), use of nonamiodarone antiarrhythmic medications (HR 2.86), atrial pacing (HR 2.57), and prolonged PR interval (HR 1.009) as associated with poorer outcome. Normal sinus rhythm at implantation (HR 0.34), baseline left bundle branch block (HR 0.44), and beta-blocker use (HR 0.47) were associated with improved outcome. In a multivariable model, high RV systolic pressure (HR 3.71, 95% confidence interval 1.31 to 10.4), renal insufficiency (HR 3.18, 95% confidence interval 1.29 to 7.86), and atrial fibrillation (HR 4.22, 95% confidence interval 1.54 to 11.6) remained significant. In conclusion, despite resynchronization, patients with high RV pressures have significantly decreased survival after adjusting for significant contributing influences.

Aged↗
PubMed2004

Losartan improves regional left ventricular systolic and diastolic function in patients with hypertension: accurate evaluation using a newly developed color-coded tissue doppler imaging technique.

BACKGROUND: Angiotensin II receptor antagonists have recently been accepted as antihypertensive therapy. Tissue Doppler imaging (TDI) has been developed as a noninvasive tool to assess quantitatively regional myocardial motion abnormalities. This study was designed to determine whether our newly developed technique of color-coded TDI may be a useful means of quantifying the improvement in regional left ventricular (LV) myocardial contractility and relaxation after treatment with losartan in patients with hypertension. METHODS AND RESULTS: Losartan (50 to 100 mg) was administered for 6 months to 37 previously untreated patients with essential hypertension. Averaged myocardial velocity profiles (MVPs) for color-coded TDI were recorded in the ventricular septum and LV posterior wall before and after treatment. Peak myocardial velocities and peak myocardial velocity gradients (MVGs) in the LV walls were determined during systole and early diastole. The plasma concentration of transforming growth factor (TGF)-beta1 also was measured in all patients. Blood pressure and plasma TGF-beta1 level decreased after initiation of losartan therapy. The LV mass index and LV meridional end-systolic wall stress also decreased after treatment with losartan. LV geometry changed from a pattern consistent with concentric hypertrophy to normal geometry in 10 patients and to a pattern consistent with concentric remodeling in 5 patients, and from concentric remodeling to normal geometry in 5 patients after treatment with losartan. The ratio of early to late diastolic filling for the transmitral flow velocity increased after losartan treatment. The peak systolic and early diastolic myocardial velocities and MVGs in the ventricular septum and LV posterior wall increased after treatment with losartan, although the values 6 months after treatment with losartan were still lower than those in normal individuals. There were good correlations between changes in plasma TGF-beta1 level and changes in systolic and early diastolic MVGs 6 months after losartan. However, there were no significant correlations between changes in the systolic blood pressure and LV end-systolic wall stress and changes in the TDI parameters. CONCLUSION: Losartan improves regional LV function in patients with hypertension. Our newly developed averaged MVP and MVG measurements may be useful for accurately evaluating regional LV myocardial contractility and relaxation in these patients.

Aged↗
PubMed2005

Close coupling of systolic and diastolic function: combined assessment provides superior prediction of exercise capacity.

BACKGROUND: Isolated diastolic dysfunction is thought to account for approximately 50% of cases of heart failure. We tested the hypotheses that (1) the use of different methods for assessing systolic and diastolic function may contribute to the apparent frequency with which they are dissociated and (2) that combined assessment of systolic and diastolic function is superior to either one alone. METHODS AND RESULTS: A total of 110 patients underwent echocardiography with tissue Doppler imaging (TDI) of the mitral annulus before maximal exercise testing. The correlation between left ventricular (LV) ejection fraction (EF) and exercise capacity was weak (r = 0.199). Among patients with EF greater than 55%, those with normal exercise capacity (>7 METs) had a higher systolic velocity of the mitral annulus than those achieving less than 7 METs (9.6 +/- 0.3 versus 7.5 +/- 0.4 cm/s, P = .001). The mitral annular systolic (Sa) and early diastolic (Ea) velocities each correlated moderately with exercise tolerance (r = 0.40 and 0.49, respectively). Sa and Ea correlated highly with each other (r = 0.79, P < .001). The sum of isovolumic contraction and relaxation times measured from TDI correlated moderately with exercise duration (r = -0.59). A combined index of systolic and diastolic function that includes isovolumic contraction and relaxation times and ejection time had the best correlation with achieved METs (r = -0.73, P < .001). A TDI index of cardiac performance higher than 0.52 had excellent sensitivity (86%) and specificity (100%) for predicting reduced exercise tolerance lower than 7 METs. CONCLUSION: When assessed with the same technique, LV systolic and diastolic function are tightly linked. A TDI-derived combined index of myocardial performance is the best predictor of exercise capacity.

Adult↗
PubMed2004

Enhanced sarcolemmal Ca2+ efflux reduces sarcoplasmic reticulum Ca2+ content and systolic Ca2+ in cardiac hypertrophy.

OBJECTIVE: Recent work has identified reductions in the systolic Ca(2+) transient in cardiac disease states. The aim of the present study was to identify the mechanisms responsible for perturbations of intracellular calcium homeostasis in isolated cardiac myocytes and determine if such changes can quantitatively explain the reduced systolic Ca(2+) transient. METHODS: Left ventricular hypertrophy (LVH) was induced by aortic coarctation in adult ferrets. Changes in intracellular Ca(2+) regulation, sarcolemmal Ca(2+) fluxes and SR function were measured in single left ventricular cardiac myocytes. RESULTS: Cardiac hypertrophy was associated with a 29% increase in action potential duration (APD(90)); a 48% reduction in the amplitude of and 19% slowing in the rate of decay of the systolic Ca(2+) transient; a 20% decrease in SR Ca(2+) content and a 36% increase in inward Na(+)-Ca(2+) exchange current for a given change in [Ca(2+)](i) (all P<0.05). Peak L-type Ca(2+) current density, integrated Ca(2+) influx and SERCA2a protein levels remained unchanged in hypertrophy. By determining the relationship between SR Ca(2+) content and systolic Ca(2+), the reduction in SR Ca(2+) content quantitatively explained the smaller systolic Ca(2+) transient. The reduced SR Ca(2+) content also accounted for a smaller fractional release of Ca(2+) from the SR and lower gain of excitation contraction coupling in cardiac hypertrophy. The increased sarcolemmal-mediated Ca(2+) efflux was sufficient to explain the reduction in SR Ca(2+) content. CONCLUSIONS: The findings indicate that the primary mechanism underlying the smaller systolic Ca(2+) transient amplitude in cardiac hypertrophy is decreased SR Ca(2+) content occurring as a consequence of reduced SR Ca(2+)-ATPase-mediated Ca(2+) uptake and increased sarcolemmal-mediated Ca(2+) efflux from the cell. The increased Na(+)-Ca(2+) exchange-mediated current for a given change in intracellular Ca(2+) concentration provides a mechanism for the development of arrhythmias in the face of a reduced SR Ca(2+) load in cardiac hypertrophy.

Action Potentials↗