Acute correction of electromechanical dyssynchrony and response to cardiac resynchronization therapy

Predictive value of apical rocking and septal flash for subclinical left ventricular systolic dysfunction in complete left bundle branch block patients with normal left ventricular ejection fraction

BACKGROUND

This study aimed to evaluate the effects of apical rocking(ApRock) and septal flash(SF) on left ventricular function in complete left bundle branch block(CLBBB) patients with normal left ventricular ejection fraction(LVEF), with the goal of improving risk stratification and clinical decision-making for these patients.

METHODS

Seventy-five CLBBB patients with normal LVEF, and 30 age- and sex-matched controls were enrolled in the study. Three independent physicians visually assessed the presence of ApRock and SF and left ventricular global longitudinal strain(LVGLS) and the standard deviation of time-to-peak strain in 18 segments(Ts-SD) were evaluated using two-dimensional speckle-tracking echocardiography.

RESULTS

CLBBB patients with normal LVEF had significantly decreased LV function and synchrony as evidenced by LVGLS and Ts-SD, and CLBBB patients with either ApRock or SF had lower LVGLS than those without ApRock or SF. LVGLS were further decreased and Ts-SD was further increased in CLBBB patients with both ApRock and SF (P < 0.001). Logistic regression analysis revealed that both ApRock (OR, 4.13; P = 0.04) and SF (OR, 4.12; P = 0.03) were independently associated with LVGLS>-20 %. Combination of ApRock and SF showed the highest area under the curve for identifying LVGLS>-20 %. Furthermore, combination of ApRock and SF improved reclassification compared to ApRock alone.

CONCLUSION

CLBBB patients with normal LVEF showed impaired left ventricular systolic function. The presence of both ApRock and SF was a stronger indicator of subclinical left ventricular impairment compared to either one alone, suggesting that increased attention should be paid to CLBBB patients with normal LVEF, particularly those with both ApRock and SF.

Device-therapy in chronic heart failure: Cardiac contractility modulation versus cardiac resynchronization therapy

AIMS

Cardiac implantable electrical devices such as cardiac resynchronization therapy with defibrillator (CRT-Ds) or cardiac contractility modulation (CCMs) are therapy options for patients with symptomatic heart failure (HF) and reduced left ventricular ejection fraction (LVEF) despite optimal medical treatment. As yet, a comparison between both devices has not been performed.

METHODS AND RESULTS

The Mannheim Cardiac Resynchronization Therapy Registry (MARACANA) and the Mannheim Cardiac Contractility Modulation Observational Study (MAINTAINED) included all patients who received CRTs or CCMs in our medical centre between 2012 and 2021. For the present analysis, we retrospectively compared patients provided with either CRT-Ds (n = 220) or CCMs with additional defibrillators (n = 105) regarding New York Heart Association classification (NYHA), LVEF, tricuspid annular plane systolic excursion (TAPSE), QRS-width and other HF modification aspects after 12 months. Before implantation, CCM patients presented with lower LVEF (23.6 ± 6.2 vs. 26.3 ± 6.5%) and worse NYHA (3.03 ± 0.47 vs. 2.81 ± 0.48, both P < 0.05), compared with CRT-D patients. Follow-up improvements in NYHA (2.43 ± 0.67 vs. 2.28 ± 0.72), LVEF (30.5 ± 10.7 vs. 35.2 ± 10.5%) and TAPSE (17.2 ± 5.2 vs. 17.1 ± 4.8 to 18.9 ± 3.4 vs. 17.3 ± 3.6 mm, each P < 0.05) were comparable. The intrinsic QRS-width was stable with CCM (109.1 ± 18 vs. 111.7 ± 19.7 ms, P > 0.05), while the paced QRS-width with CRT-D after 12 months was lower than intrinsic values at baseline (157.5 ± 16.5 vs. 139.2 ± 16 ms, P < 0.05). HF hospitalizations occurred more often for CCM than CRT-D patients (45.7 vs. 16.8%/patient years, odds ratio 4.2, P < 0.001).

CONCLUSIONS

Chronic heart failure patients could experience comparable 12-month improvements in functional status and ventricular reverse remodelling, with appropriately implanted CCMs and CRT-Ds. Differences in HF hospitalization rates may be due to the more advanced HF of CCM patients at implantation.

Ventricular dysfunction consequences of mechanical dyssynchrony in isolated complete right bundle branch block versus left bundle branch block

Background

Complete bundle branch block in individuals without structural heart disease is known as isolated complete bundle branch block. Isolated complete left bundle branch block (CLBBB) is correlated with ventricular dysfunction secondary to dyssynchrony; however, few studies have investigated isolated complete right bundle branch block (CRBBB), which was previously considered benign but was recently found to be associated with adverse cardiovascular outcomes. This study aimed to evaluate cardiac mechanical synchrony, and systolic and diastolic function in patients with isolated CRBBB and compare cardiac synchrony and function to patients with isolated CLBBB.

Methods

This cross-sectional study was conducted at The First Hospital of China Medical University in Shenyang, China, from 2020 to 2021. A total of 44 isolated CRBBB patients, 44 isolated CLBBB patients, and 42 healthy subjects were enrolled in the study. Transthoracic echocardiography was performed in all subjects. Synchrony parameters, including the mechanical dispersion of the right ventricle [the standard deviation of time to the peak longitudinal strain of six right ventricular (RV) segments] and atrioventricular dyssynchrony parameter [the ratio of left ventricular (LV) diastolic filling time to the time interval between two adjacent R waves (RR interval) measured by tissue Doppler imaging]. RV and LV function were assessed by the global longitudinal strain (GLS) of six RV segments and 18 LV segments, and the ratio of the peak early diastolic flow velocity to annular velocity (E/e') of the tricuspid valve and mitral valve. Statistical analyses were performed, including an analysis of variance, Pearson correlation analysis, and linear regression analysis.

Results

Compared with the healthy subjects, the mechanical dispersion of the right ventricle was significantly increased, and ventricular function was impaired as evidenced by the decreased RV GLS and LV GLS, and the increased E/e' of the tricuspid valve and mitral valve in the isolated CRBBB patients (all P<0.001). Moreover, compared with the isolated CLBBB patients, the mechanical dispersion of the right ventricle and E/e' of the tricuspid valve were increased, and RV GLS was significantly reduced in the isolated CRBBB patients (all P<0.001). Mechanical dispersion of the right ventricle was independently associated with RV GLS [coefficient, 0.13; 95% confidence interval (CI): 0.004-0.26; P=0.04] in the isolated CRBBB patients. RV GLS (coefficient, 0.10; 95% CI: 0.01-0.20; P=0.03) and the ratio of the LV diastolic filling time to the RR interval measured (coefficient, -0.30; 95% CI: -0.53 to -0.07; P=0.01) were independent factors of LV GLS.

Conclusions

The isolated CRBBB patients had impaired cardiac mechanical synchrony and ventricular function, and more decreased RV synchrony and function than the isolated CLBBB patients. Right intraventricular synchrony was independently associated with RV systolic dysfunction in patients with isolated CRBBB. Atrioventricular synchrony and RV systolic function were independently associated with the LV systolic function. Therefore, comprehensive evaluations of echocardiography results and close monitoring is required for isolated CRBBB patients.

Potential Underestimation of Left Ventricular Mechanical Dyssynchrony in Dyssynchrony and Outcomes Assessment

Objective

Left ventricular (LV) mechanical dyssynchrony (LVMD) is fundamental to the progression of heart failure and ventricular remodeling. The status of LVMD in different patterns of bundle branch blocks (BBB) is unclear. In this study, we analyzed the relationship between LVMD and left ventricular systolic dysfunction using real-time three-dimensional echocardiography (RT-3DE).

Methods

RT-3DE and conventional two-dimensional echocardiography were performed on 68 patients with left bundle branch block (LBBB group), 106 patients with right bundle branch block (RBBB group), and 103 patients without BBB (Normal group). The RT-3DE data sets provided time-volume analysis for global and segmental LV volumes. The LV systolic dyssynchrony index (LVSDI) was calculated using the standard deviation (SD) and maximal difference (Dif) of time to minimum segmental volume (tmsv) for LV segments adjusted by the R-R interval. LVMD was considered if the LVSDI (Tmsv-16-SD) was greater than or equal to 5%.

Results

LVSDI is negatively and significantly correlated with left ventricular ejection fraction (LVEF), but not with BBB or QRS duration. The proportion of LVMD in the LBBB, RBBB, and Normal group was 30.88%, 28.30%, and 25.24%, respectively, and there was no significant difference.

Conclusion

In dilated cardiomyopathy, LVMD is more closely related to LVEF reduction than QRS morphology and duration.

Comparison of electrocardiographic parameters between left bundle optimized cardiac resynchronization therapy (LOT-CRT) and left bundle branch pacing-cardiac resynchronization therapy (LBBP-CRT)

BACKGROUND

In patients undergoing cardiac resynchronization therapy using left bundle branch area pacing (LBBP-CRT), the addition of a coronary sinus lead, that is, Left bundle optimized CRT (LOT-CRT) might confer additional benefits.

OBJECTIVES

To compare the electrocardiographic characteristics between LBBP-CRT and LOT-CRT MATERIALS AND METHODS: Patients with non-ischemic cardiomyopathy (NICMP) and left bundle branch block (LBBB) with left ventricular ejection fraction <35% who underwent implantation of an atrial lead, a left bundle lead, and a coronary sinus lead were included in this prospective study. Digital 12-lead electrocardiograms were recorded in three pacing modes-AAI, DDD with pacing from the LBB lead (LBBP-CRT), and DDD with pacing from both left bundle and coronary sinus leads (LOT-CRT). QRS duration (QRSd), QRS area, QT interval, and T peak-T end (TpTe) intervals were compared.

RESULTS

Among 24 patients, QRSd reduced from 167 ± 21.2 ms to 134.5 ± 23.6 ms with LBBP-CRT (p < .001) and 129.5 ± 18.6 ms with LOT-CRT (p < .001) without a significant difference between LBBP-CRT and LOT-CRT (p = .15). Patients with QRS duration with LBBP-CRT > 131 ms showed a significant reduction in QRSd with LOT-CRT (p = .03). QT interval was reduced with both modes of CRT. LOT-CRT was associated with a greater reduction in QRS area (p = .001), TpTe interval (p = .03), and TpTe/QT ratio (p = .013) compared to LBBP-CRT.

CONCLUSIONS

In patients with NICMP and LBBB, there was no significant difference in QRSd with LOT-CRT compared to LBBP-CRT. However, in patients with QRSd > 131 ms after LBBP-CRT, LOT-CRT resulted in a significantly narrower QRS.

Pulse arrival time variation as a non-invasive marker of acute response to cardiac resynchronization therapy

AIMS

Successful cardiac resynchronization therapy (CRT) shortens the pre-ejection period (PEP) which is prolonged in the left bundle branch block (LBBB). In a combined animal and patient study, we investigated if changes in the pulse arrival time (PAT) could be used to measure acute changes in PEP during CRT implantation and hence be used to evaluate acute CRT response non-invasively and in real time.

METHODS AND RESULTS

In six canines, a pulse transducer was attached to a lower limb and PAT was measured together with left ventricular (LV) pressure by micromanometer at baseline, after induction of LBBB and during biventricular pacing. Time-to-peak LV dP/dt (Td) was used as a surrogate for PEP. In twelve LBBB patients during implantation of CRT, LV and femoral pressures were measured at baseline and during five different pacing configurations. PAT increased from baseline (277 ± 9 ms) to LBBB (313 ± 16 ms, P < 0.05) and shortened with biventricular pacing (290 ± 16 ms, P < 0.05) in animals. There was a strong relationship between changes in PAT and Td in patients (r2 = 0.91). Two patients were classified as non-responders at 6 months follow-up. CRT decreased PAT from 320 ± 41 to 298 ± 39 ms (P < 0.05) in the responders, while PAT increased by 5 and 8 ms in the two non-responders.

CONCLUSION

This proof-of-concept study indicates that PAT can be used as a simple, non-invasive method to assess the acute effects of CRT in real time with the potential to identify long-term response in patients.

Heart failure: an update from the last years and a look at the near future

In the last years, major progress occurred in heart failure (HF) management. Quadruple therapy is now mandatory for all the patients with HF with reduced ejection fraction. Whilst verciguat is becoming available across several countries, omecamtiv mecarbil is waiting to be released for clinical use. Concurrent use of potassium-lowering agents may counteract hyperkalaemia and facilitate renin-angiotensin-aldosterone system inhibitor implementations. The results of the EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure With Preserved Ejection Fraction (EMPEROR-Preserved) trial were confirmed by the Dapagliflozin in Heart Failure with Mildly Reduced or Preserved Ejection Fraction (DELIVER) trial, and we now have, for the first time, evidence for treatment of also patients with HF with preserved ejection fraction. In a pre-specified meta-analysis of major randomized controlled trials, sodium-glucose co-transporter-2 inhibitors reduced all-cause mortality, cardiovascular (CV) mortality, and HF hospitalization in the patients with HF regardless of left ventricular ejection fraction. Other steps forward have occurred in the treatment of decompensated HF. Acetazolamide in Acute Decompensated Heart Failure with Volume Overload (ADVOR) trial showed that the addition of intravenous acetazolamide to loop diuretics leads to greater decongestion vs. placebo. The addition of hydrochlorothiazide to loop diuretics was evaluated in the CLOROTIC trial. Torasemide did not change outcomes, compared with furosemide, in TRANSFORM-HF. Ferric derisomaltose had an effect on the primary outcome of CV mortality or HF rehospitalizations in IRONMAN (rate ratio 0.82; 95% confidence interval 0.66-1.02; P = 0.070). Further options for the treatment of HF, including device therapies, cardiac contractility modulation, and percutaneous treatment of valvulopathies, are summarized in this article.

Shortening of time-to-peak left ventricular pressure rise (Td) in cardiac resynchronization therapy

Aims

We tested the hypothesis that shortening of time‐to‐peak left ventricular pressure rise (Td) reflect resynchronization in an animal model and that Td measured in patients will be helpful to identify long‐term volumetric responders [end‐systolic volume (ESV) decrease >15%] in cardiac resynchronization therapy (CRT).

Methods

Td was analysed in an animal study (n = 12) of left bundle‐branch block (LBBB) with extensive instrumentation to detect left ventricular myocardial deformation, electrical activation, and pressures during pacing. The sum of electrical delays from the onset of pacing to four intracardiac electrodes formed a synchronicity index (SI). Pacing was performed at baseline, with LBBB, right and left ventricular pacing and finally with biventricular pacing (BIVP). We then studied Td at baseline and with BIVP in a clinical observational study in 45 patients during the implantation of CRT and followed up for up to 88 months.

Results

We found a strong relationship between Td and SI in the animals (R = 0.84, P < 0.01). Td and SI increased from narrow QRS at baseline (Td = 95 ± 2 ms, SI = 141 ± 8 ms) to LBBB (Td = 125 ± 2 ms, SI = 247 ± 9 ms, P < 0.01), and shortened with biventricular pacing (BIVP) (Td = 113 ± 2 ms and SI = 192 ± 7 ms, P < 0.01). Prolongation of Td was associated with more wasted deformation during the preejection period (R = 0.77, P < 0.01). Six patients increased ESV by 2.5 ± 18%, while 37 responders (85%) had a mean ESV decrease of 40 ± 15% after more than 6 months of follow‐up. Responders presented with a higher Td at baseline than non‐responders (163 ± 26 ms vs. 121 ± 19 ms, P < 0.01). Td decreased to 156 ± 16 ms (P = 0.02) with CRT in responders, while in non‐responders, Td increased to 148 ± 21 ms (P < 0.01). A decrease in Td with BIVP to values similar or below what was found at baseline accurately identified responders to therapy (AUC 0.98, P < 0.01). Td at baseline and change in Td from baseline was linear related to the decrease in ESV at follow‐up. All‐cause mortality was high among six non‐responders (n = 4), while no patients died in the responder group during follow‐up.

Conclusions

Prolongation of Td is associated with cardiac dyssynchrony and more wasted deformation during the preejection period. Shortening of a prolonged Td with CRT in patients accurately identifies volumetric responders to CRT with incremental value on top of current guidelines and practices. Thus, Td carries the potential to become a biomarker to predict long‐term volumetric response in CRT candidates.

Acute correction of electromechanical dyssynchrony and response to cardiac resynchronization therapy

Aims

Echocardiographic measures of dyssynchrony at baseline have not demonstrated a good ability to predict response to cardiac resynchronization therapy (CRT). The purpose of this study was to determine if the acute correction of electromechanical dyssynchrony, assessed by the change in simple pulsed‐Doppler measures, was related to CRT response at 6 months.

Methods and results

Echocardiography was performed at baseline and at pre‐discharge after CRT implantation. Intraventricular, interventricular, and atrioventricular dyssynchrony were evaluated by the left pre‐ejection interval (LPEI), the interventricular mechanical delay, and the ratio of left ventricular filling time to RR interval, respectivelxy. A patient was considered responder if he/she was alive without hospitalization for heart failure and had an absolute increase of left ventricular ejection fraction (LVEF) >5 points. Forty‐eight patients (mean age 67 ± 11 years, 73% male, mean LVEF 30 ± 5%) were included. CRT led to an acute correction of intraventricular and interventricular dyssynchrony but not to an acute correction of atrioventricular dyssynchrony. There were 31 (65%) responders at 6 months. Two factors were independently associated with CRT response in multivariate analysis: ischemic cardiomyopathy (odds ratio 0.19, 95% confidence interval 0.04–0.87; P= 0.032) and delta LPEI (odds ratio 1.03 per 1 ms decrease, 95% confidence interval 1.01–1.05; P = 0.007). By receiver operating characteristic analysis, the optimal cut‐off value of delta LPEI was −16 ms. The proportion of responders in patients without ischemic cardiomyopathy and with a delta LPEI greater than −16 ms was 85%.

Conclusions

Acute correction of intraventricular electromechanical dyssynchrony evaluated by the LPEI predicted CRT response at 6 months.