Conventional therapy with an ACE inhibitor diminishes left ventricular dyssynchrony during the progression of heart failure

Relationship between intraventricular mechanical dyssynchrony and left ventricular systolic and diastolic performance: An in vivo experimental study

Left ventricular mechanical dyssynchrony (LVMD) refers to the nonuniformity in mechanical contraction and relaxation timing in different ventricular segments. We aimed to determine the relationship between LVMD and LV performance, as assessed by ventriculo-arterial coupling (VAC), LV mechanical efficiency (LV_eff ), left ventricular ejection fraction (LVEF), and diastolic function during sequential experimental changes in loading and contractile conditions. Thirteen Yorkshire pigs submitted to three consecutive stages with two opposite interventions each: changes in afterload (phenylephrine/nitroprusside), preload (bleeding/reinfusion and fluid bolus), and contractility (esmolol/dobutamine). LV pressure-volume data were obtained with a conductance catheter. Segmental mechanical dyssynchrony was assessed by global, systolic, and diastolic dyssynchrony (DYS) and internal flow fraction (IFF). Late systolic LVMD was related to an impaired VAC, LV_eff , and LVEF, whereas diastolic LVMD was associated with delayed LV relaxation (logistic tau), decreased LV peak filling rate, and increased atrial contribution to LV filling. The hemodynamic factors related to LVMD were contractility, afterload, and heart rate. However, the relationship between these factors differed throughout the cardiac cycle. LVMD plays a significant role in LV systolic and diastolic performance and is associated with hemodynamic factors and intraventricular conduction.

The Therapeutic Benefit of Upgrade to Cardiac Resynchronization Therapy in Patients with Pacing Induced Cardiomyopathy

Background

Pacing-induced cardiomyopathy (PICM) is an important cause of heart failure in patients with a right ventricular pacing burden. Recent evidence suggests that an upgrade to cardiac resynchronization therapy (CRT) may confer benefit in PICM.

Objective

To assess the extent and identify predictors of improvement following upgrade to CRT in patients with PICM.

Methods

We retrospectively analyzed 43 patients undergoing CRT upgrade for PICM over the 10-year period of 2011 to 2021 at our center. All patients with PICM who underwent device upgrade from a dual- or single-chamber ventricular pacemaker to CRT were included. PICM was defined as a decrease of ≥10% in left ventricular ejection fraction (LVEF), resulting in an LVEF <50% among patients with ≥20% Right ventricular pacing burden without an alternative cause for cardiomyopathy.

Results

LVEF significantly improved from 28.7% preupgrade to 44.3% post-CRT upgrade (P < .01). Of 37 patients with severe LV dysfunction, 34 (91.9%) improved to an LVEF >35% and 13 (35.1%) improved to an LVEF >50%. The LV end-diastolic diameter decreased from 5.9 cm preupgrade to 5.4 cm postupgrade (P < .01). Using linear regression, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use was associated with significant LVEF improvement (+7.21%, P = .05). We observed a low rate of complications, and 1 in 4 CRT upgrades required venoplasty (n = 10 of 43, 23.3%).

Conclusion

We provide further evidence for the benefit of CRT upgrade in the management of patients with PICM.

Renal sympathetic denervation inhibits the development of left ventricular mechanical dyssynchrony during the progression of heart failure in dogs

Background

The purpose of this study was to investigate whether transcatheter renal sympathetic denervation (RSD) interfere with the development of left ventricular (LV) mechanical dyssynchrony during the progression of heart failure (HF).

Methods

Nineteen beagles were randomly divided into sham-operated group (six dogs), control group (seven dogs), and RSD group (six dogs). Sham-operated group were implanted with pacemakers without pacing; Control group were implanted with pacemakers and underwent 3 weeks of rapid right ventricular pacing; and RSD group underwent catheter-based RSD bilaterally and were simultaneously implanted with pacemakers. Both LV strain and LV dyssynchrony were analyzed via 2D speckle-tracking strain echocardiography to evaluate LV function. Longitudinal dyssynchrony was determined as the standard deviation for time-to-peak speckle-tracking strain on apical 4- and 2-chamber views. Radial and circumferential dyssynchrony was determined as the standard deviation for time-to-peak speckle-tracking strain in mid- and base-LV short-axis views. Each myocardial function was also evaluated by averaging the peak systolic strains. LV systolic pressure (LVSP) and LV end-diastolic pressure (LVEDP) were measured. The LV interstitial fibrosis was determined by histological analysis. Plasma angiotensin II (Ang II), aldosterone and norepinephrine (NE) levels were also measured.

Results

After 3 weeks, all of the dogs in both the control and RSD groups showed greater LV end-diastolic volume compared with the sham-operated group; however, the dogs in the RSD group had a higher LV ejection fraction (LVEF) than the dogs in the control group (p < 0.001). The LV systolic strains were higher in the RSD group than in the control group (p < 0.001 for longitudinal, circumferential and radial strain, respectively). The levels of LV dyssynchrony were lower in the RSD group than in the control group (p < 0.001 for longitudinal, circumferential and radial dyssynchrony, respectively). Compared with dogs with control alone, RSD dogs had lower LV end-diastolic pressures and less fibrous tissue. The levels of plasma Ang II, aldosterone and NE were lower in the RSD group than in the control group.

Conclusions

RSD inhibites the development of left ventricular mechanical dyssynchrony during the progression of heart failure in dogs.

Assessment of left ventricular dyssynchrony in patients with psoriasis

BACKGROUND

Psoriasis is an inflammatory disorder, which has been reported to be associated with cardiovascular (CV) risks. Although increased CV risks in psoriasis are well established, there are no data about changes of contraction synchrony in psoriasis. Therefore, we aimed to study the left ventricular (LV) contraction synchrony in patients with psoriasis with narrow QRS and normal ejection fraction.

METHODS

Fifty patients with psoriasis and 50 age- and sex-matched control subjects were included in the study. LV dyssynchrony was investigated by color-coded tissue Doppler imaging.

RESULTS

In the psoriasis group, the mean high-sensitive C-reactive protein values were significantly higher compared with the controls. Peak A velocity, deceleration time, isovolumetric relaxation time, and E/E' values were higher in the psoriasis group; however, E/A ratio and average Em were higher in the control group. LV systolic dyssynchrony parameters [including standard deviation of Ts of the 12 LV segments (Ts-SD-12), maximal difference in Ts between any two of the 12 LV segments, standard deviation of Ts of the six basal LV segments, and maximal difference in Ts between any two of the six basal LV segments] were found to be higher in the psoriasis group. The patients with ventricular dyssynchrony (a Ts-SD-12 >34.4 ms) were higher in the psoriasis group than the control group (34% vs. 6%, P < 0.01).

CONCLUSION

In patients with psoriasis with normal ejection fractions and narrow QRS, LV systolic dyssynchrony is an early manifestation of heart involvement and may coexist with diastolic dysfunction.

Assessment of left ventricular dyssynchrony in dipper and non-dipper hypertension

BACKGROUND

Ventricular dyssynchrony is an co-determinant of progression and exacerbation of heart failure (HF). The co-existence of ventricular dyssynchrony with hypertension (HT) and HF were shown, however there is no data regarding the effect of circadian rhythm of blood pressure (BP) on ventricular synchrony. Therefore, we aimed to study the left ventricular synchrony in dipper and non-dipper normotensive and hypertensive participants.

METHODS

Participants (n = 142) were categorized into four groups as "Normotensive-Dipper" (NT-D) (n = 40), "Normotensive-Non-dipper" (NT-ND) (n = 30), "Hypertensive-Dipper" (HT-D) (n = 38) and "Hypertensive-Non-dipper" (HT-ND) (n = 34). Left ventricular dyssynchrony was investigated by color-coded tissue Doppler imaging.

RESULTS

Non-dippers had higher 24-h and night-time BP both in normotensives and hypertensives. The incidence of ventricular dyssynchrony (a Ts-SD-12 > 34.4 ms) was higher in the hypertensive group (47.2% vs 24.3%, p = 0.005). The frequency of ventricular dyssynchrony was higher in the HT-ND group than the HT-D group (58.8% vs 36.8%, p = 0.05); however, the frequency of ventricular dyssynchrony was similar among the normotensives (26.7% vs 22.5%, p = 0.45). Ts-SD-12 and Ts-12 were higher in NT-ND group than the NT-D group.

CONCLUSIONS

Non-dipping BP pattern was associated with impaired left ventricular contraction synchrony in both normotensive and hypertensive participants, which may be related with short- and long-term effects of HT on myocardium.

Left ventricular dyssynchrony is an early manifestation of heart involvement in sickle cell anemia

BACKGROUND

Sickle cell anemia (SCA) is the most common inherited anemia. Although heart involvement in SCA is well-established, there is no data about changes of contraction synchrony in SCA. Therefore, we aimed to study the left ventricular contraction synchrony in SCA patients with narrow QRS and normal ejection fraction (EF).

METHODS

Thirty-six patients with SCA and 37 age- and gender-matched control subjects were included in the study. Left ventricular dyssynchrony was investigated by color-coded tissue Doppler imaging.

RESULTS

The SCA patients had lower hemoglobin (Hb) and higher ferritin, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left ventricular mass index (LVMI), and pulmonary artery pressure. Peak A velocity, Dt, and E/E' values were higher in the SCA group however, E/A ratio and average Em were higher in the control group. LV systolic dyssynchrony parameters including Ts-SD-12, Ts-12, Ts-SD-6, and Ts-6 were found to be higher in SCA group when compared with controls. In addition to that, the patients with ventricular dyssynchrony (a Ts-SD-12 > 34.4 msec) were higher in the SCA group than the control group (55.6% vs. 8.1%, P < 0.001). In the correlation analysis, systolic dyssynchrony parameters were found to be correlated with Hb, ferritin, LVMI, E/A, Dt, Em.

CONCLUSION

Our results revealed that in SCA patients with normal EF and narrow QRS, left ventricular systolic dyssynchrony was an early manifestation of heart involvement and might be coexisted with or preceding diastolic dysfunction.

Dynamic dyssynchrony and impaired contractile reserve of the left ventricle in beta-thalassaemia major: an exercise echocardiographic study

BACKGROUND

Performance of the left ventricle during exercise stress in thalassaemia patients is uncertain. We aimed to explore the phenomenon of dynamic dyssynchrony and assess contractile reserve in patients with beta-thalassaemia major and determine their relationships with myocardial iron load.

METHODS AND RESULTS

Thirty-two thalassaemia patients (16 males), aged 26.8 ± 6.9 years, without heart failure and 17 healthy controls were studied. Their left ventricular (LV) volumes, ejection fraction, systolic dyssynchrony index (SDI), and myocardial acceleration during isovolumic LV contraction (IVA) were determined at rest and during submaximal bicycle exercise testing using 3-dimensional and tissue Doppler echocardiography. Myocardial iron load as assessed by T2* cardiac magnetic resonance in patients were further related to indices of LV dyssynchrony and contractile reserve. At rest, patients had significantly greater LV SDI (p<0.001) but similar IVA (p = 0.22) compared with controls. With exercise stress, the prevalence of mechanical dyssynchrony (SDI>4.6%, control+2SD) increased from baseline 25% to 84% in patients. Δ SDI(exercise-baseline) correlated with exercise-baseline differences in LV ejection fraction (p<0.001) and stroke volume (p = 0.006). Compared with controls, patients had significantly less exercise-induced increase in LV ejection fraction, cardiac index, and IVA (interaction, all p<0.05) and had impaired contractile reserve as reflected by the gentler IVA-heart rate slope (p = 0.018). Cardiac T2* in patients correlated with baseline LV SDI (r = -0.44, p = 0.011) and IVA-heart rate slope (r = 0.36, p = 0.044).

CONCLUSIONS

Resting LV dyssynchrony is associated with myocardial iron load. Exercise stress further unveils LV dynamic dyssynchrony and impaired contractile reserve in patients with beta-thalassaemia major.

Renin-angiotensin system blockers are associated with reduced mortality and heart failure hospitalization in patients paced for complete atrioventricular block

BACKGROUND

Right ventricular apical pacing can cause dyssynchronous activation of the ventricles, increase sympathetic activation, cause abnormalities in myocardial perfusion, worsen cardiac output and endothelial function, and may be associated with adverse cardiovascular effects. The use of rennin-angiotensin system blockers (RASBs) may be beneficial in counteracting these potentially harmful effects of right ventricular pacing.

OBJECTIVE

To explore the impact of RASB use on the outcome in patients with right ventricular pacemakers implanted for complete atrioventricular (AV) block.

METHODS

Patients implanted with right ventricular pacemakers for complete AV block between 1994 and 2009 were identified from the Tayside Pacing Registry. Cox proportional hazards model was used to assess differences in all-cause mortality and congestive heart failure hospitalizations for those receiving RASB during follow-up, adjusted for confounding variables. We also performed 2 sensitivity analyses--a propensity score-matched analysis and time-dependent analyses--to minimize bias.

RESULTS

Eight hundred twenty patients (57% men; median age 73 years; range 22-103 years) received pacemakers for complete AV block between 1994 and 2008 (54% dual-chamber pacemaker and 46% ventricular demand pacemaker). Two hundred seventy-eight (34%) patients had received RASBs. Mean follow-up was 4.9 ± 4.6 years, with 540 (65%) deaths. RASB use was independently associated with significantly reduced mortality (adjusted hazard ratio 0.67; 95% confidence interval 0.47-0.94; P = .017) and reduced heart failure hospitalization (adjusted hazard ratio 0.42; 95% confidence interval 0.17-0.92; P <.001).

CONCLUSIONS

This study suggests that RASBs may confer outcome benefits in patients with right ventricular pacemakers implanted for complete AV block.