Impaired Left and Right Ventricular Systolic and Diastolic Function in Response to Exercise in Patients with Diastolic Dysfunction

BACKGROUND

Diastolic dysfunction (DD) is associated with exercise intolerance. To evaluate mechanisms of exercise intolerance in patients with DD, we performed bicycle stress echocardiography.

METHOD AND RESULTS

Doppler measurements were performed at baseline, during exercise and recovery in 26 patients (58 ± 11 years) with DD and normal left ventricular ejection fraction and 6 normal controls (53 ± 5 years). Compared to controls, patients achieved similar target heart rates but lower METs (5.5 ± 2 vs. 9.8 ± 3, P < 0.01) and a higher peak pulmonary artery pressure (PAP) at peak exercise (50 ± 13 vs. 32 ± 7 mmHg, P < 0.01) despite similar PAP at rest and similar mean blood pressure at peak exercise (110.4 ± 18.0 vs. 106.9 ± 11.4 mmHg, P = NS). In patients versus controls, mitral E/E' was similar at baseline (10 ± 3 vs. 8 ± 1.3, P = NS) but higher at recovery (11 ± 2 vs. 7 ± 2, P < 0.05), % mitral filling time was shorter at baseline, onset, and peak exercise, whereas % LV and RV ejection time was similar to controls throughout exercise. Compared to controls, lateral mitral annular S' (11.8 ± 2.5 cm/sec vs. 14.9 ± 1.9 cm/sec, P < 0.02) and tricuspid annular S' (14.8 ± 4.1 cm/sec vs. 19.4 ± 4.0 cm/sec, P < 0.05) were lower at peak exercise in patients.

CONCLUSION

Diastolic filling time is reduced at rest and stress while LV ejection time increases normally during exercise in DD. There is a reduced systolic reserve in LV and RV during exercise in DD. These mechanisms contribute to exercise intolerance and elevation of left atrial and PAP in patients with DD.

Left Bundle Branch Block Negatively Affects Coronary Flow Velocity Reserve and Myocardial Contractile Reserve in Nonischemic Dilated Cardiomyopathy

BACKGROUND

Coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery (LAD) and myocardial contractile reserve are often impaired in nonischemic dilated cardiomyopathy (DCM). Whether they are affected by the presence of left bundle branch block (LBBB) remains unaddressed. The aim of the study was to investigate how LBBB influences CFVR of the LAD and myocardial contractile reserve in patients with DCM.

METHODS

One hundred eighty-one patients with DCM (116 men; mean age, 63 ± 12 years) underwent high-dose dipyridamole (0.84 mg/kg over 6 min) stress echocardiography with CFVR evaluation of the LAD by Doppler. All patients had ejection fractions < 40% (mean, 31 ± 8%) and angiographically normal or near normal coronary arteries. CFVR was defined as the ratio between hyperemic peak and basal peak diastolic coronary flow velocities. CFVR > 2.0 was considered normal. Inotropic reserve was defined as rest-stress variation in wall motion score index ≥ 0.20. This was a prospective analysis of an unselected sample consecutively enrolled and retrospectively selected.

RESULTS

The study group was separated on the basis of presence (n = 122) or absence (n = 59) of LBBB. Patients with LBBB were older (64 ± 11 vs 59 ± 12 years, P = .004) and had reduced resting ejection fractions (30 ± 9% vs 33 ± 7%, P = .02), CFVR of the LAD (1.96 ± 0.41 vs 2.23 ± 0.73, P = .001), and myocardial contractile reserve (variation in wall motion score index, -0.18 ± 0.17 vs -0.33 ± 0.28; P < .001). On multivariate logistic regression analysis, resting ejection fraction (hazard ratio [HR], 1.15; 95% CI, 1.03-1.29; P = .01), smoking habit (HR, 2.63; 95% CI, 1.23-5.62; P = .01), and LBBB (HR, 2.29; 95% CI, 1.05-5.04; P = .04) were independently associated with reduced CFVR, while restrictive transmitral pattern (HR, 2.56; 95% CI, 1.18-5.55; P = .02), end-diastolic volume (HR, 0.98; 95% CI, 0.67-0.99; P = .02), and LBBB (HR, 2.20; 95% CI, 1.11-4.34; P = .02) independently predicted reduced myocardial contractile reserve.

CONCLUSIONS

CFVR during vasodilator stress echocardiography is a suitable tool for assessing microvascular dysfunction in routine clinical practice. Patients with DCM and LBBB show more severe forms of microvascular dysfunction, which is related to worse left ventricular function and lack of contractile reserve. Therapeutic interventions to restore microvascular function may improve left ventricular function parameters in patients with DCM.

Left ventricular dyssynchrony in patients with heart failure and preserved ejection fraction

AIMS

Mechanical dyssynchrony has been postulated to play a pathophysiologic role in heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

We quantified left ventricular (LV) systolic dyssynchrony in 130 HFpEF patients with NYHA class II-IV symptoms, ejection fraction (EF) ≥45%, and NT-proBNP levels >400 pg/mL enrolled in the PARAMOUNT trial, and compared them to 40 healthy controls of similar age and gender. Dyssynchrony was assessed by 2D speckle tracking as standard deviation (SD) of time to peak longitudinal systolic strain in 12 ventricular segments and related to measures of systolic and diastolic function. Heart failure with preserved ejection fraction patients (62% women, mean age of 71 ± 9 years, body mass index of 30.2 ± 5.9 kg/m(2), systolic blood pressure 139 ± 15 mmHg) demonstrated significantly greater dyssynchrony than controls (SD of time to peak longitudinal strain; 90.6 ± 50.9 vs. 56.4 ± 33.5 ms, P < 0.001), even in the subset of patients (n = 63) with LVEF ≥55% and narrow QRS (≤100 ms). Among HFpEF patients, dyssynchrony was related to wider QRS interval, higher LV mass, and lower early diastolic tissue Doppler myocardial velocity (E'). Greater dyssynchrony remained significantly associated with worse diastolic function even after restricting the analysis to patients with EF≥55% and adjusting for age, gender, systolic blood pressure, LV mass index, and LVEF.

CONCLUSION

Heart failure with preserved EF is associated with greater mechanical dyssynchrony compared with healthy controls of similar age and gender. Within an HFpEF population, the severity of dyssynchrony is related to the width of QRS complex, LV hypertrophy, and diastolic dysfunction.

Association of left ventricular diastolic function with systolic dyssynchrony: a population study

AIMS

Left ventricular (LV) (dys)synchrony has an important impact on LV function and structure. Our study aimed to describe the distribution and determinants of LV mechanical delay indexes in the general population and to assess an association of different Doppler indexes reflecting LV diastolic function with LV mechanical delay indexes.

METHODS AND RESULTS

In 200 subjects enrolled in a family-based population study (46.5% women; mean age, 57.9; 48% hypertensive), we performed echocardiography with tissue synchronization imaging (TSI) and two-dimensional speckle tracking. We measured the maximum difference in time to peak systolic velocity between any 2 of 12 LV segments (Ts-max); the standard deviation of time to peak systolic velocity of 12 segments (Ts-sd); the difference in time to peak systolic velocity and strain between septal and lateral LV walls and the strain delay index in septal and lateral walls [septal and lateral (SDI)]. In univariable and multivariable regression analyses, TSI indexes and lateral SDI independently increased with age (P ≤ 0.027) and body mass index (P ≤ 0.010). Ts-max and Ts-sd also increased with female sex (P ≤ 0.0002) and decreased with heart rate (P ≤ 0.0004). Septal SDI only increased with female sex (P < 0.0001). Among the Doppler indexes of LV diastolic function, only E/e' was significantly and positively associated with TSI indexes (P ≤ 0.037) and lateral SDI (P = 0.0026), but not with septal SDI (P = 0.69). In participants with advanced stage of LV diastolic dysfunction, TSI indexes were prolonged compare with subjects with normal LV diastolic function (P ≤ 0.002).

CONCLUSION

We demonstrated that in unselected subjects LV diastolic dysfunction was associated with mechanical LV dyssynchrony as assessed by echocardiography.

Impact of antihypertensive treatment on left ventricular systolic dyssynchrony in treatment-naïve hypertensive patients

Dyssynchrony is common in asymptomatic patients with hypertension. We sought to investigate the impact of antihypertensive treatment on dyssynchrony in patients with hypertension. A total of sixty patients who had uncomplicated hypertension that had never been treated (treatment-naïve hypertensive patients) underwent echocardiographic evaluations of left ventricular (LV) dyssynchrony at baseline and after a 6-month treatment with antihypertensive drugs. The measured parameters were as follows: (1) the s.d. of 12 LV-segment time-to-peak systolic velocities (Ts-SD12), and (2) the maximal difference between peak systolic velocities of any 2 of the 12 segments (Ts-Max). Patients with Ts-SD12 ≥ 33 ms or Ts-Max ≥ 100 ms were regarded as having LV systolic dyssynchrony. Patients with systolic dyssynchrony (group 1, n = 29) and without systolic dyssynchrony (group 2, n = 31) were compared. Among the patients in group 1, antihypertensive treatment significantly improved LV systolic dyssynchrony (ΔTs-SD12, -13.1 ms; P<0.001 and ΔTs-Max, -34.0 ms; P = 0.003), whereas it did not demonstrate additional benefit among group 2 patients. The change in LV systolic dyssynchrony was significantly associated with changes in the mean annulus E' velocity, mean annulus S' velocity and mean annulus E'/A' ratio, but not with changes in blood pressure and LV mass index. It is likely that chronic antihypertensive treatment could reverse the LV systolic dyssynchrony and simultaneously improve subclinical systolic and diastolic function in patients with hypertension and LV systolic dyssynchrony.

Diastolic dysfunction and intraventricular dyssynchrony are restored by low intensity exercise training in obese men

The aim of this study was to evaluate the impact of a low-intensity training program on subclinical cardiac dysfunction and on dyssynchrony in moderately obese middle aged men. Ten obese and 14 age-matched normal-weight men (BMI: 33.6 ± 1.0 and 24.2 ± 0.5 kg/m(2)) were included. Obese men participated in an 8-week low-intensity training program without concomitant diet. Cardiac function and myocardial synchrony were assessed by echocardiography with tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE). At baseline, obese men showed diastolic dysfunction on standard echocardiography, lower strain values (systolic strain: 15.9 ± 0.9 vs. 18.8 ± 0.3%, diastolic strain rate: 0.81 ± 0.09 vs. 1.05 ± 0.06 s(-1)), and significant intraventricular dyssynchrony (systolic: 13.3 ± 2.1 vs. 5.4 ± 2.1 ms, diastolic: 17.4 ± 3.2 vs. 9.1 ± 2.1 ms) (P < 0.05 vs. controls for all variables). Training improved aerobic fitness, decreased systolic blood pressure and heart rate, and reduced fat mass without weight loss. Diastolic function, strain values (systolic strain: 17.4 ± 0.9%, diastolic strain rate: 0.96 ± 0.12 s(-1)) and intraventricular dyssynchrony (systolic: 3.3 ± 1.7 ms, diastolic: 5.5 ± 3.4 ms) improved significantly after training (P < 0.05 vs. baseline values for all variables), reaching levels similar to those of normal-weight men. In conclusion, in obese men, a short and easy-to-perform low intensity training program restored diastolic function and cardiac synchrony and improved body composition without weight loss.

Long-term cardiovascular outcomes in patients with angina pectoris presenting with bundle branch block

Long-term outcomes of unselected patients with angina pectoris and bundle branch block (BBB) on initial electrocardiogram are not well established. The Olmsted County Chest Pain Study is a community-based cohort of 2,271 consecutive patients presenting to 3 Olmsted County emergency departments with angina from 1985 through 1992. Patients were followed for major adverse cardiovascular events (MACEs) including death, myocardial infarction, stroke, and revascularization at 30 days and over a median follow-up period of 7.3 years and for mortality only through a median of 16.6 years. Cox models were used to estimate associations between BBB and cardiovascular outcomes. Mean age of the cohort on presentation was 63 years, and 58% were men. MACEs at 30 days occurred in 11% with right BBB (RBBB), 8.8% with left BBB (LBBB), and 6.4% in patients without BBB (p = 0.17). Over a median follow-up of 7.3 years, patients with BBB were at higher risk for MACEs (RBBB, hazard ratio [HR] 1.85, 95% confidence interval [CI] 1.44 to 2.38, p <0.001; LBBB, HR 2.04, 95% CI 1.62 to 2.56, p <0.001) compared to those without BBB. Over a median of 16.6 years, the 2 BBB groups had lower survival rates than patients without BBB (RBBB, HR 2.19, 95% CI 1.73 to 2.78, p <0.001; LBBB, HR 3.32, 95% CI 2.67 to 4.13, p ≤0.001), but after adjustment for multiple risk factors an increased risk of mortality for LBBB remained significant. In conclusion, appearance of LBBB or RBBB in patients presenting with angina predicts adverse long-term cardiovascular outcomes compared to patients without BBB.