Gerben J. de Roest

Comparison between three-dimensional speckle-tracking echocardiography and cardiac magnetic resonance imaging for quantification of left ventricular volumes and function

AIMS We evaluated the accuracy of three-dimensional speckle-tracking echocardiography (3DSTE) to evaluate left ventricular (LV) volumes, ejection fraction (EF), and global circumferential strain (CS) in comparison with cardiac magnetic resonance imaging (MRI) in a healthy population. METHODS AND RESULTS A total of 45 out of 50 consecutive healthy subjects (38 males, age 45 ± 15 years) successfully underwent both 3DSTE and MRI on the same day. Three-dimensional echocardiography data sets were analysed using speckle tracking to measure LV end-diastolic and end-systolic volumes, EF, and global CS. With MRI, the method of discs approximation was used to obtain volumes and the EF, whereas CS was acquired using myocardial tissue tagging. Inter-technique comparisons included regression and the Bland-Altman analysis. For quantification of LV volumes, 3DSTE correlated well with MRI (r: 0.75-0.81), but volumes were significantly underestimated with relatively large biases (13-34 mL) and wide limits of agreement (SD: 11-25 mL). However, excellent accuracy was revealed for measurement of EF by 3DSTE with a good correlation (r: 0.91), minimal bias, and narrow limits of agreement (0.6 ± 1.7%) compared with MRI. For measurement of CS, a large mean bias was found between techniques (10.0%), despite narrow limits of agreement (SD: 1.7%) and a good correlation between techniques (r: 0.80). CONCLUSION Although 3DSTE-derived LV volumes are underestimated in most patients compared with MRI, measurement of the LVEF revealed excellent accuracy. Measurements of CS were systematically greater (i.e. more negative) with 3DSTE than MRI, which likely reflects various inter-technique differences that preclude direct comparability of their measurements.

Prediction of long-term outcome of cardiac resynchronization therapy by acute pressure-volume loop measurements.

Invasive assessment of acute haemodynamic response to biventricular pacing has been proposed as a tool to determine individual response and to optimize the effects of CRT. However, the long‐term results of this approach have been poorly studied. The present study relates acute haemodynamic effects of CRT to long‐term outcome.

Loss of opposite left ventricular basal and apical rotation predicts acute response to cardiac resynchronization therapy and is associated with long-term reversed remodeling

BACKGROUND Normal left ventricular (LV) torsion is caused by opposite basal and apical rotation. Opposite rotation can be lost in heart failure, but might be restored by pacing; therefore, the predictive value of the loss of opposite base-apex rotation in heart failure patients for the response to cardiac resynchronization therapy (CRT) was studied. METHODS AND RESULTS In 34 CRT candidates and 12 controls, basal and apical LV rotations were calculated using magnetic resonance image tagging. Loss of opposite rotation was quantified by the correlation between both rotation curves: a negative correlation indicates normal, opposite rotation and a positive correlation indicates that base and apex rotate in the same direction. In patients, LV pressure was measured invasively during biventricular stimulation. Acute response to CRT was defined by >10% increase in dP/dt(max) relative to baseline. LV volume was determined at baseline and 8 months follow-up using echocardiography. The base-apex rotation correlation (BARC) was significantly higher in acute responders (n=22) than in nonresponders (n=12) and controls (0.64+/-0.51, -0.23+/-0.67, and -0.68+/-0.22, respectively; P=.001). The sensitivity and specificity for prediction of acute response were 82% and 83%, respectively, at a cutoff value of 0.5. At follow-up, volumes could be analyzed in 18 patients. In the group with BARC >0.5, end-diastolic volume decreased by 7% (NS), end-systolic volume by 16%, and ejection fraction increased by 28% (both P=.02), whereas in the group with BARC <0.5, no significant changes were observed. CONCLUSIONS The loss of opposite base-apex rotation in patients eligible for CRT is an excellent predictor of acute response and is associated with LV reverse remodeling.

Scar tissue–guided left ventricular lead placement for cardiac resynchronization therapy in patients with ischemic cardiomyopathy: An acute pressure-volume loop study

BACKGROUND Response to cardiac resynchronization therapy (CRT) is hampered by the extent and location of left ventricular (LV) scar tissue. It is commonly advised to avoid scar tissue while placing the LV lead. However, whether individual patients benefit from this strategy remains unclear. METHODS Thirty-two CRT candidates with ischemic cardiomyopathy were enrolled from 2 successive clinical trials (TBS and E-pot study). Magnetic resonance imaging with late contrast enhancement was performed to assess location, degree and transmurality of LV scar tissue. Patients underwent invasive pressure-volume loop measurements to assess acute LV pump function changes during pacing at posterolateral (PL) and anterolateral LV sites. RESULTS In the study population (26 [81%] men, ejection fraction [EF] 22% ± 8%, QRS 149 ± 20 milliseconds), baseline mean stroke work (SW) and dP/dtmax were 4.4 ± 2.2 L∙mmHg and 849 ± 212 mmHg/s, respectively. The extent of scar tissue was inversely related to the acute increase in SW during pacing (R = -0.53, P = .002). Stimulating PL scar tissue resulted in deterioration of pump function (∆SW -17% ± 17%, P = .018), whereas pacing PL viable tissue led to an increase in pump function (∆SW +62% ± 51%, P < .001). Switching from pacing at the location of scar tissue, irrespective of the scar location, to viable tissue showed a significant increase in SW (-8% ± 20% vs +20 ± 40, P = .004). CONCLUSIONS The extent of LV scar tissue is inversely related to acute pump function improvement during CRT. Pacing at the location of (transmural) scar tissue at any site of the LV will generally deteriorate LV pump function. Placing the LV lead over viable myocardium significantly improves pump function as compared with pacing at the location of scar tissue in patients with ischemic cardiomyopathy.

Effects of QRS Duration and Pacing Location on Pressure-Volume Loop Evaluation of Cardiac Resynchronization Therapy in End-Stage Heart Failure

Cardiac resynchronization therapy (CRT) decreases the morbidity and mortality in patients with end-stage heart failure. However, patient selection remains challenging, because a considerable 30% to 50% do not respond. Controversy exists on the cutoff values for the QRS duration and the optimal lead location. The present study relates these parameters on an individual basis to acute pump function improvement using invasively obtained pressure-volume loops. Fifty-seven patients with symptomatic end-stage heart failure were included in our temporary biventricular stimulation study and were grouped according to the QRS duration (QRS <20 ms, QRS ≥120 ms but <150 ms, and QRS ≥150 ms). All patients underwent pressure-volume loop assessment of the response to biventricular pacing, comparing the baseline measurements to both right ventricular apex pacing combined with a left ventricular lead in the posterolateral and anterolateral region of the LV. Group analysis during conventional (posterolateral and right ventricular apex) CRT did not show improvement in stroke work and dP/dt(max) (-2%, p = NS; and -7%; p <0.001) in the narrow QRS group but a significant increase in the intermediate (+27%, p = 0.020, and +5%, p = 0.044) and wide (+48%, p = 0.002, and +18%, p <0.001) QRS groups. CRT using the anterolateral and right ventricular apex configuration evoked a consistently lower response compared to posterolateral and right ventricular apex, resulting in a significant hemodynamic deterioration in the narrow QRS group. However, analysis on an individual basis identified 25% of patients with narrow QRS duration showing possible hemodynamic benefit from CRT compared to 83% of patients with intermediate and wide QRS combined. In contrast, 15% of patients had deterioration by conventional (posterolateral right ventricular apex) CRT in the intermediate and wide QRS groups compared to 31% in the narrow QRS group; 19% of patients could be improved by lead placement in the anterolateral rather than the posterolateral region. In conclusion, the acute hemodynamic response to CRT is generally in line with the long-term results from large randomized trials; however, the individual variation is large. The temporary biventricular stimulation protocol might aid in individual patient selection and in research aiming at a reduction of nonresponders and improvement in lead positioning.

Prediction of Acute Response to Cardiac Resynchronization Therapy by Means of the Misbalance in Regional Left Ventricular Myocardial Work

BACKGROUND Patients with left ventricular (LV) dyssynchrony have a marked misbalance in LV myocardial work distribution, with wasted work in the septum and increased work in the lateral wall. We hypothesized that a low septum-to-lateral wall (SL) myocardial work ratio at baseline predicts acute LV pump function improvement during cardiac resynchronization therapy (CRT). METHODS AND RESULTS Twenty patients (age 65 ± 10 y, 15 men) underwent cardiac magnetic resonance (CMR) tagging for regional LV circumferential strain assessment and invasive pressure-volume loop assessment at baseline and during biventricular pacing. Segmental work at baseline was calculated from regional strain rate and LV pressure. Subsequently, the SL work ratio was calculated and related to acute pump function (stroke work [SW]) improvement during CRT. During biventricular pacing, SW increased by 33% (P <.001). SL work ratio at baseline was found to be significantly related to SW improvement by means of CRT (R = -0.54; P = .015). Moreover, it proved to be the only marker that was significantly related to acute response to CRT, whereas QRS duration and other measures of dyssynchrony or dyscoordination were not. CONCLUSIONS The contribution of the septum to LV work varies widely in CRT candidates with left bundle branch block. The lower the septal contribution to myocardial work at baseline, the higher the acute pump function improvement that can be achieved during CRT.

Bifocal left ventricular stimulation or the optimal left ventricular stimulation site in cardiac resynchronization therapy: a pressure–volume loop study

AIMS Several implantation strategies have been proposed to improve response to cardiac resynchronization therapy (CRT), including bifocal left ventricular (LV) stimulation and optimal single-LV lead placement. This study aimed to compare these two strategies during invasive pressure-volume (PV) loop measurements. METHODS AND RESULTS Thirty-three patients eligible for CRT were included [21 (64%) men, 20 (61%) ischaemic aetiology, QRS 155 ± 23 ms], and underwent cardiac magnetic resonance (CMR) imaging and invasive PV loop measurements. Left ventricular pump function was characterized by stroke work (SW) and dP/dtmax (5.1 ± 3.4 L mmHg and 856 ± 190 mmHg/s, respectively). Haemodynamic response was assessed during stimulation at single-LV sites and during bifocal LV [anterolateral and posterolateral (PL)] stimulation. Response during bifocal LV stimulation was not significantly higher compared with standard PL pacing (SW; β = 9.4 ± 5.4, P = 0.080; dP/dtmax, β = 0.2 ± 1.9, P = 0.922). However, mean pump function improvement was significantly higher during stimulation at the optimal LV site compared with bifocal LV stimulation (SW; β = 12.7 ± 5.1, P = 0.012; dP/dtmax, β = 3.3 ± 1.2, P = 0.020). Myocardial tissue properties were assessed by CMR tissue tagging. Mechanical activation at the optimal LV site was significantly more delayed compared with the worst LV site (431 ± 93 ms vs. 326 ± 127 ms; P = 0.004). CONCLUSION Stimulation at the optimal LV site showed a significantly higher pump function improvement compared with bifocal LV stimulation. Mechanical activation at the optimal LV site was significantly more delayed compared with the non-optimal LV site. In general, these results suggest that implantation of a second LV lead yields no additional benefit over implantation of one optimally placed LV lead. However, a bifocal approach might be beneficial in the individual patient.

ELECTRICAL RESYNCHRONIZATION IS NOT RELATED TO HEMODYNAMIC RESPONSE IN CARDIAC RESYNCHRONIZATION THERAPY

Cardiac resynchronization therapy (CRT) is based on restoring left ventricular dyssynchrony. It is known that CRT induced changes in QRS duration poorly predict hemodynamic effect. This study assessed invasively obtained endocardial and epicardial left ventricular activation with and without CRT and

THE INFLUENCE OF RIGHT VENTRICULAR PACING ON RESPONSE TO BIVENTRICULAR PACING: AN ACUTE PRESSURE-VOLUME LOOP STUDY

Background: Cardiac resynchronization therapy (CRT) is an established therapy for end-stage heart failure. It is currently recommended to position the left ventricular (LV) lead at the postero-lateral (PL) wall. However, the position of the right ventricular (RV) lead remains controversial, since it may be associated with adverse hemodynamic effects. This may partly explain non-response to CRT. We hypothesized that RV pacing during biventricular pacing signiicantly modulates response. We studied the acute invasive hemodynamic response of RV, LV and biventricular pacing.