Functional Contribution of Circumferential Versus Longitudinal Strain: Different Concepts Suggest Conflicting Results

Prognosis evaluation of chronic inflammatory cardiomyopathy with ring-like late gadolinium enhancement

AIMS

Ring-like late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging is a special LGE pattern in patients with chronic inflammatory cardiomyopathy (infl-CMP), which is associated with cardiac dysfunction and ventricular remodelling and attributed to viral infection followed by bacterial and parasitic infections. Data on the combination of CMR imaging and clinical parameters that can add long-term prognostic value in patients with infl-CMP are still rare. We aimed to evaluate the prognostic value of CMR in risk stratification in this kind of patients.

METHODS AND RESULTS

A total of 319 consecutive patients with clinically suspected myocarditis were retrospectively identified. Forty-seven patients with ring-like LGE on CMR who diagnosed as infl-CMP, and 72 patients with other LGE pattern were eligible for standardized follow-up. The left ventricle (LV) and right ventricle function and mass were analyses by CMR. Myocardial strain of the ventricles was evaluated by feature tracking. Major (cardiac death, resuscitated cardiac arrest, ventricular assist device, transplantation, and appropriate implantable cardioverter-defibrillator shock) and minor (rehospitalization due to heart failure and sustained atrial fibrillation) adverse cardiovascular events were assessed during follow-up since the date of nCMR examination. Cox proportional hazards model was used to investigate which of the prognostic factors identified by univariable analysis were significantly associated with cardiac events. In the ring-like LGE group, adverse cardiac events occurred in 14 (31.11%) patients, including 7 deaths (15.56%), 6 (13.33%) heart-failure hospitalizations, and 1 (2.22%) case of sustained atrial fibrillation during the mean follow-up period of 70.15 ± 45.68 months (interquartile range: 32.83-103.71 months). No major or minor adverse cardiac event occurred in the other LGE pattern group, except rehospitalization in one patient due to arrhythmia. Further analyses of ring-like LGE group by univariable and Multivariable Cox proportional hazard regression analysis showed that body mass index (BMI) (hazard ratio [HR]: 0.54, 95% confidence interval [CI]: 0.40-0.73, P = 0.000), right ventricle cardiac index (RVCI) (HR: 0.31, 95% CI: 0.14-0.71, P = 0.002), LV basal peak circumferential strain (LV-PCS_basal ) (HR: 1.26, 95% CI: 1.11-1.43, P = 0.000) were independently associated with the long-term outcome. Receiver operator characteristic curve indicated that the cut-off of LV-PCS_Basal was -7.95%, and it has added prognostic value to BMI and RVCI.

CONCLUSIONS

For infl-CMP patients with ring-like LGE on CMR, low BMI and RVCI were associated with a poor prognosis. LV-PCS_Basal with a cut-off of -7.95% can add prognostic value for patients with infl-CMP who have ring-like LGE.

Atrioventricular plane displacement and regional function to predict outcome in pulmonary arterial hypertension

To investigate if left and right atrioventricular plane displacement (AVPD) or regional contributions to SV are prognostic for outcome in patients with pulmonary arterial hypertension (PAH). Seventy-one patients with PAH and 20 sex- and age-matched healthy controls underwent CMR. Myocardial borders and RV insertion points were defined at end diastole and end systole in cine short-axis stacks to compute biventricular volumes, lateral (SVlat%) and septal (SVsept%) contribution to stroke volume. Eight atrioventricular points were defined at end diastole and end systole in 2-, 3- and 4-chamber cine long-axis views for computation of AVPD and longitudinal contribution to stroke volume (SVlong%). Cut-off values for survival analysis were defined as two standard deviations above or below the mean of the controls. Outcome was defined as death or lung transplantation. Median follow-up time was 3.6 [IQR 3.7] years. Patients were 57 ± 19 years (65% women) and controls 58 ± 15 years (70% women). Biventricular AVPD, SVlong% and ejection fraction (EF) were lower and SVlat% was higher, while SVsept% was lower in PAH compared with controls. In PAH, transplantation-free survival was lower below cut-off for LV-AVPD (hazard ratio [HR] = 2.1, 95%CI 1.2-3.9, p = 0.02) and RV-AVPD (HR = 9.8, 95%CI 4.6-21.1, p = 0.005). In Cox regression analysis, lower LV-AVPD and RV-AVPD inferred lower transplantation-free survival (LV: HR = 1.16, p = 0.007; RV: HR = 1.11, p = 0.01; per mm decrease). LV-SVlong%, RV-SVlong%, LV-SVlat%, RV-SVlat%, SVsept% and LV- and RVEF did not affect outcome. Low left and right AVPD were associated with outcome in PAH, but regional contributions to stroke volume and EF were not.

Layer-specific strain and dyssynchrony index alteration in new-onset systemic lupus erythematosus patients without cardiac symptoms

Background

Layer-specific speckle-tracking echocardiography (STE) is a noninvasive approach that assesses subclinical left ventricular dysfunction. We aimed to investigate the (I) alteration of layer-specific STE parameters and the dyssynchrony index; and (II) the disease parameters associated with layer-specific STE change in drug-naïve patients with new-onset systemic lupus erythematosus (SLE) without cardiac symptoms.

Methods

Thirty-five drug-naïve patients with new-onset SLE and twenty-five healthy controls were enrolled. All individuals received both conventional echocardiographic and two-dimensional STE assessment. The data of layer-specific global longitudinal strain (GLS), global circumferential strain (GCS), and peak systolic dispersion (PSD) were acquired in layer-specific STE.

Results

All patients had a normal left ventricular ejection fraction (LVEF)(mean LVEF: 58%) and conventional echocardiographic parameters were comparable between patients and controls. Decreased layer-specific GLS and elevated PSD were observed in SLE patients (whole layer GLS: -17.6%±3.0% versus -19.3%±2.6%, P=0.02; endocardial GLS: -20.0%±3.2% versus -22.1%±3.0%, P=0.01; epicardial GLS: -15.6%±2.7% versus -16.8%±2.4%, P=0.04; PSD: 41.0±18.9 versus 28.8±10.1 msec, P=0.007). In contrast, there was no difference in layer-specific GCS at three different levels between patients and controls (P>0.05). More severely impaired GLS was observed in patients with higher disease activity, high-risk antiphospholipid antibody (aPL) profile, or renal involvement. The PSD was increased in patients with higher disease activity or a high-risk aPL profile. Correlational analysis showed that GLS at three layers and PSD correlated with high-sensitivity C-reactive protein (hsCRP) levels (whole GLS: r=0.662, P<0.001; endocardial GLS: r=0.637, P<0.001; epicardial GLS: r=0.658, P<0.001; PSD: r=0.390, P=0.021). PSD correlated with epicardial GLS (r=0.360, P=0.047), when treating the hsCRP level, renal involvement, aPL profile, and disease activity as control variables. Multivariate regression showed the hsCRP level and epicardial GLS were predictors of layer-specific GLS impairment and elevated PSD, respectively.

Conclusions

Drug-naive patients with new-onset SLE are likely to have subclinical GLS impairment and left ventricular dyssynchrony, even in the presence of normal LVEF. SLE-related risk factors are associated with these dysfunctions.

Underfilling decreases left ventricular function in pulmonary arterial hypertension

To evaluate the association between impaired left ventricular (LV) longitudinal function and LV underfilling in patients with pulmonary arterial hypertension (PAH). Thirty-nine patients with PAH and 18 age and sex-matched healthy controls were included. LV volume and left atrial volume (LAV) were delineated in short-axis cardiac magnetic resonance (CMR) cine images. LV longitudinal function was assessed from atrio-ventricular plane displacement (AVPD) and global longitudinal strain (GLS) was assessed using feature tracking in three long-axis views. LV filling was assessed by LAV and by pulmonary artery wedge pressure (PAWP) using right heart catheterisation. Patients had a smaller LAV, LV volume and stroke volume as well as a lower LV-AVPD and LV-GLS than controls. PAWP was 6 [IQR 5––9] mmHg in patients. LV ejection fraction did not differ between groups. LV stroke volume correlated with LV-AVPD (r = 0.445, p = .001), LV-GLS (r = − 0.549, p < 0.0001) and LAVmax (r = .585, p < 0.0001). Furthermore, LV-AVPD (r = .598) and LV-GLS (r = − 0.675) correlated with LAVmax (p < 0.0001 for both). Neither LV-AVPD, LV-GLS, LAVmax nor stroke volume correlated with PAWP. Impaired LV longitudinal function was associated with low stroke volume, low PAWP and a small LAV in PAH. Small stroke volumes and LAV, together with normal LA pressure, implies that the mechanism causing reduced LV longitudinal function is underfilling rather than an intrinsic LV dysfunction in PAH.

Range Variability in CMR Feature Tracking Multilayer Strain across Different Stages of Heart Failure

Heart failure (HF) is associated with progressive ventricular remodeling and impaired contraction that affects distinctly various regions of the myocardium. Our study applied cardiac magnetic resonance (CMR) feature tracking (FT) to assess comparatively myocardial strain at 3 distinct levels: subendocardial (Endo-), mid (Myo-) and subepicardial (Epi-) myocardium across an extended spectrum of patients with HF. 59 patients with HF, divided into 3 subgroups as follows: preserved ejection fraction (HFpEF, N = 18), HF with mid-range ejection fraction (HFmrEF, N = 21), HF with reduced ejection fraction (HFrEF, N = 20) and a group of age- gender- matched volunteers (N = 17) were included. Using CMR FT we assessed systolic longitudinal and circumferential strain and strain-rate at Endo-, Myo- and Epi- levels. Strain values were the highest in the Endo- layer and progressively lower in the Myo- and Epi- layers respectively, this gradient was present in all the patients groups analyzed but decreased progressively in HFmrEF and further on in HFrEF groups. GLS decreased with the severity of the disease in all 3 layers: Normal > HFpEF > HFmrEF > HFrEF (Endo-: −23.0 ± 3.5 > −20.0 ± 3.3 > −16.4 ± 2.2 > −11.0 ± 3.2, p < 0.001, Myo-: −20.7 ± 2.4 > −17.5.0 ± 2.6 > −14.5 ± 2.1 > −9.6 ± 2.7, p < 0.001; Epi-: −15.7 ± 1.9 > −12.2 ± 2.1 > −10.6 ± 2.3 > −7.7 ± 2.3, p < 0.001). In contrast, GCS was not different between the Normal and HFpEF (Endo-: −34.5 ± 6.2 vs −33.9 ± 5.7, p = 0.51; Myo-: −21.9 ± 3.8 vs −21.3 ± 2.2, p = 0.39, Epi-: −11.4 ± 2.0 vs −10.9 ± 2.3, p = 0.54) but was, as well, markedly lower in the systolic heart failure groups: Normal > HFmrEF > HFrEF (Endo-: −34.5 ± 6.2 > −20.0 ± 4.2 > 12.3 ± 4.2, p < 0.001; Myo-: −21.9 ± 3.8 > −13.0 ± 3.4 > −8.0 ± 2.7. p < 0.001; Epi-: −11.4 ± 2.0 > −7.9 ± 2.3 > −4.5 ± 1.9. p < 0.001). CMR feature tracking multilayer strain assessment identifies large range differences between distinct myocardial regions. Our data emphasizes the importance of sub-endocardial myocardium for cardiac contraction and thus, its predilect role in imaging detection of functional impairment. CMR feature tracking offers a convenient, readily available, platform to evaluate myocardial contraction with excellent spatial resolution, rendering further details about discrete areas of the myocardium. Using this technique across distinct groups of patients with heart failure (HF), we demonstrate that subendocardial regions of the myocardium exhibit much higher strain values than mid-myocardium or subepicardial and are more sensitive to detect contractile impairment. We also show comparatively higher values of circumferential strain compared with longitudinal and a higher sensitivity to detect contractile impairment. A newly characterized group of patients, HF with mid-range ejection fraction (EF), shows similar traits of decompensation but has relatively higher strain values as patients with HF with reduced EF.

Heart filling exceeds emptying during late ventricular systole in patients with systolic heart failure and healthy subjects - a cardiac MRI study

Background

Total heart volume (THV) within the pericardium is not constant throughout the cardiac cycle and THV would intuitively be lowest at end systole. We have, however, observed a phase shift between ventricular outflow and atrial inflow which causes the minimum THV to occur before end systole. The aims were to explain the mechanism of the late‐systolic net inflow to the heart and determine whether this net inflow is affected by increased cardiac output or systolic heart failure.

Methods and Results

Healthy controls (n = 21) and patients with EF<35% (n = 14) underwent magnetic resonance imaging with flow measurements in vessels to and from the heart, and this was repeated in nine controls during 140 μgram kg⁻¹ min⁻¹ adenosine infusion. Minimum THV occurred 78 ± 6 ms before end of systolic ejection (8 ± 1% of the cardiac cycle) in controls. The late‐systolic net inflow was 12·3 ± 1·1 ml or 6·0 ± 0·5% of total stroke volume (TSV). Cardiac output increased 66 ± 8% during adenosine but late‐systolic net inflow to the heart did not change (P = 0·73). In patients with heart failure, late‐systolic net inflow of the heart′s left side was lower (3·4 ± 0·5%) compared to healthy subjects (5·3 ± 0·6%, P = 0·03).

Conclusions

Heart size increases before end systole due to a late‐systolic net inflow which is unaffected by increased cardiac output. This may be explained by inertia of blood that flows into the atria generated by ventricular systole. The lower late‐systolic net inflow in patients with systolic heart failure may be a measure of decreased ventricular filling due to decreased systolic function, thus linking systolic to diastolic dysfunction.