Left Ventricular Geometry and Risk of Sudden Cardiac Arrest in Patients With Severely Reduced Ejection Fraction

Left Ventricular Mass as a Modulator of Ventricular Arrhythmia Risk and Sex Differences Following CRT for Non-Ischemic Cardiomyopathy and LBBB

BACKGROUND

Risk for ventricular arrhythmias (VA) following cardiac resynchronization therapy (CRT) has been associated with ischemic disease/scar, sex, and possibly left ventricular mass (LVM).

OBJECTIVE

To evaluate sex differences and baseline/post-implant change [Δ] of LVM on VA risk after CRT implant among patients with non-ischemic cardiomyopathy (NICM) and left bundle branch block.

METHODS

Among patients meeting the criteria, baseline and follow-up echocardiographic images were obtained for LVM assessment. VA events were reported from device diagnostics and therapies. VA risk was stratified by ROC (Youden-index cut-point) for baseline LVM and ΔLVM, and baseline patient characteristics using a multivariable Cox regression model.

RESULTS

118 patients (71[60.2%] female, age 60.5 ±11.3 years, LVEF 19.2 ±7.0%, QRS 165.6 ±20 ms, LVM 313.9 ±108.8 g) were enrolled and followed for median 90 (IQR 44-158) months. Thirty-five (29.6%) patients received appropriate shocks or anti-tachycardia pacing at a median of 73.5 (IQR 25-130) months post-implant. Males had a higher VA incidence (male 18/47 [38.3%] vs. female 17/71 [23.9%], P=0.02). Baseline LVM >308.9g separated patients with higher VA risk (P=0.001). Less than a 20% decrease in LVM increased VA risk (P<0.001). Baseline LVM was the only baseline characteristic predicting VA events in the Cox regression model (Hazard ratio 1.01 [95%CI, 1.001-1.009], Log-rank P=0.003). Sex differences in VA risk were eliminated by the baseline LVM parameters.

CONCLUSION

VA risk after CRT in NICM was associated with baseline LV >308.9g and a decrease in LVM ≤ 20%, without sex differences.

Feasibility of Left Ventricle Lead Implantation in Cardiac Resynchronization Therapy Guided by Gated SPECT and Ventricular Remodeling

BACKGROUND

Cardiac resynchronization therapy (CRT) may benefit patients with advanced heart failure (HF). Abnormal eccentricity index by gated SPECT is related to structural and functional alterations of the left ventricle (LV).

OBJECTIVE

The aim of this study is to evaluate the feasibility of LV lead implantation guided by phase analysis and its relationship to ventricular remodeling.

METHODS

Eighteen patients with indication for CRT underwent myocardial scintigraphy for implant orientation, and eccentricity and ventricular shape parameters were evaluated. P < 0.05 was adopted as statistical significance.

RESULTS

At baseline, most patients were classified as NYHA 3 (n = 12). After CRT, 11 out of 18 patients were reclassified to a lower degree of functional limitation. In addition, patients' quality of life was improved post-CRT. Significant reductions were observed in QRS duration, PR interval, end-diastolic shape index, end-systolic shape index, stroke volume, and myocardial mass post-CRT. The CRT LV lead was positioned concordant, adjacent, and discordant in 11 (61.1%), 5 (27.8%), and 2 (11.1%) patients, respectively. End-systolic and end-diastolic eccentricity demonstrated reverse remodeling post-CRT.

CONCLUSIONS

LV lead implantation in CRT guided by gated SPECT scintigraphy is feasible. The placement of the electrode concordant or adjacent to the last segment to contract was a determinant of reverse remodeling.

CarDiac magnEtic Resonance for prophylactic Implantable-cardioVerter defibrillAtor ThErapy in Non-Ischaemic dilated CardioMyopathy: an international Registry

AIMS

The aim of this registry was to evaluate the additional prognostic value of a composite cardiac magnetic resonance (CMR)-based risk score over standard-of-care (SOC) evaluation in a large cohort of consecutive unselected non-ischaemic cardiomyopathy (NICM) patients.

METHODS AND RESULTS

In the DERIVATE registry (www.clinicaltrials.gov/registration: RCT#NCT03352648), 1000 (derivation cohort) and 508 (validation cohort) NICM patients with chronic heart failure (HF) and left ventricular ejection fraction <50% were included. All-cause mortality and major adverse arrhythmic cardiac events (MAACE) were the primary and secondary endpoints, respectively. During a median follow-up of 959 days, all-cause mortality and MAACE occurred in 72 (7%) and 93 (9%) patients, respectively. Age and >3 segments with midwall fibrosis on late gadolinium enhancement (LGE) were the only independent predictors of all-cause mortality (HR: 1.036, 95% CI: 1.0117-1.056, P < 0.001 and HR: 2.077, 95% CI: 1.211-3.562, P = 0.008, respectively). For MAACE, the independent predictors were male gender, left ventricular end-diastolic volume index by CMR (CMR-LVEDVi), and >3 segments with midwall fibrosis on LGE (HR: 2.131, 95% CI: 1.231-3.690, P = 0.007; HR: 3.161, 95% CI: 1.750-5.709, P < 0.001; and HR: 1.693, 95% CI: 1.084-2.644, P = 0.021, respectively). A composite clinical and CMR-based risk score provided a net reclassification improvement of 63.7% (P < 0.001) for MAACE occurrence when added to the model based on SOC evaluation. These findings were confirmed in the validation cohort.

CONCLUSION

In a large multicentre, multivendor cohort registry reflecting daily clinical practice in NICM work-up, a composite clinical and CMR-based risk score provides incremental prognostic value beyond SOC evaluation, which may have impact on the indication of implantable cardioverter-defibrillator implantation.

Elevated Plasma Homocysteine Level Associated with Further Left Ventricular Structure and Function Damages in Type 2 Diabetic Patients: A Three-Dimensional Speckle Tracking Echocardiography Study

Aims: The aims of this study were to explore the left ventricular (LV) structural remodeling and its risk factors in type 2 diabetes mellitus (T2DM) patients with or without hyperhomocysteinemia (hHcy) and to detect the accompanied LV dysfunction using three-dimensional speckle tracking echocardiography (3DSTE). Methods: There were totally 80 T2DM patients with undamaged LV ejection fraction (≥55%) in this study, 40 of whom were also diagnosed with hHcy as co-morbidity. Forty age- and gender-matched controls were also recruited. The risk factors and corresponding diagnostic values for LV remodeling (LVR) were, respectively, determined using logistic regression and area under the receiver operating characteristic curves (AUC). The 3DSTE was used to measure global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS). Results: The constituent ratio of LV geometry showed significant differences among the study populations (P = 0.01). Compared with the controls, three types of LVR accounted for larger proportion in the two T2DM groups, whereas LV hypertrophy was most prevalent in those with T2DM and hHcy. Glycosylated hemoglobin (HbA1c), total plasma homocysteine (tHcy), and HbA1c plus tHcy were all significant risk factors associated with LVR in T2DM patients (AUC values: 0.741, 0.746 and 0.851, respectively). The patients with T2DM alone had significantly lower GLS and GAS than the controls (both P < 0.05). The patients with T2DM and hHcy had significantly lower GLS, GCS, GAS, and GRS than the controls (all P < 0.001), and also had significantly lower GLS, GCS, and GRS than the patients with T2DM alone (all P < 0.05). Conclusions: The 3DSTE plus conventional echocardiography could be used as an effective supplement for detecting early and occult cardiac damages in T2DM patients with plasma homocysteine at normal or elevated levels.

Left ventricular hypertrophy and sudden cardiac death

Sudden cardiac death (SCD) is among the leading causes of death worldwide, and it remains a public health problem, as it involves young subjects. Current guideline-directed risk stratification for primary prevention is largely based on left ventricular (LV) ejection fraction (LVEF), and preventive strategies such as implantation of a cardiac defibrillator (ICD) are justified only for documented low LVEF (i.e., ≤ 35%). Unfortunately, only a small percentage of primary prevention ICDs, implanted on the basis of a low LVEF, will deliver life-saving therapies on an annual basis. On the other hand, the vast majority of patients that experience SCD have LVEF > 35%, which is clamoring for better understanding of the underlying mechanisms. It is mandatory that additional variables be considered, both independently and in combination with the EF, to improve SCD risk prediction. LV hypertrophy (LVH) is a strong independent risk factor for SCD regardless of the etiology and the severity of symptoms. Concentric and eccentric LV hypertrophy, and even earlier concentric remodeling without hypertrophy, are all associated with increased risk of SCD. In this paper, we summarize the physiology and physiopathology of LVH, review the epidemiological evidence supporting the association between LVH and SCD, briefly discuss the mechanisms linking LVH with SCD, and emphasize the need to evaluate LV geometry as a potential risk stratification tool regardless of the LVEF.

Prognostic value of cardiovascular magnetic resonance left ventricular volumetry and geometry in patients receiving an implantable cardioverter defibrillator

BACKGROUND

Current indications for implantable cardioverter defibrillator (ICD) implantation for sudden cardiac death prevention rely primarily on left ventricular (LV) ejection fraction (LVEF). Currently, two different contouring methods by cardiovascular magnetic resonance (CMR) are used for LVEF calculation. We evaluated the comparative prognostic value of these two methods in the ICD population, and if measures of LV geometry added predictive value.

METHODS

In this retrospective, 2-center observational cohort study, patients underwent CMR prior to ICD implantation for primary or secondary prevention from January 2005 to December 2018. Two readers, blinded to all clinical and outcome data assessed CMR studies by: (a) including the LV trabeculae and papillary muscles (TPM) (trabeculated endocardial contours), and (b) excluding LV TPM (rounded endocardial contours) from the total LV mass for calculation of LVEF, LV volumes and mass. LV sphericity and sphere-volume indices were also calculated. The primary outcome was a composite of appropriate ICD shocks or death.

RESULTS

Of the 372 consecutive eligible patients, 129 patients (34.7%) had appropriate ICD shock, and 65 (17.5%) died over a median duration follow-up of 61 months (IQR 38-103). LVEF was higher when including TPM versus excluding TPM (36% vs. 31%, p < 0.001). The rate of appropriate ICD shock or all-cause death was higher among patients with lower LVEF both including and excluding TPM (p for trend = 0.019 and 0.004, respectively). In multivariable models adjusting for age, primary prevention, ischemic heart disease and late gadolinium enhancement, both LVEF (HR per 10% including TPM 0.814 [95%CI 0.688-0.962] p = 0.016, vs. HR per 10% excluding TPM 0.780 [95%CI 0.639-0.951] p = 0.014) and LV mass index (HR per 10 g/m2 including TPM 1.099 [95%CI 1.027-1.175] p = 0.006; HR per 10 g/m2 excluding TPM 1.126 [95%CI 1.032-1.228] p = 0.008) had independent prognostic value. Higher LV end-systolic volumes and LV sphericity were significantly associated with increased mortality but showed no added prognostic value.

CONCLUSION

Both CMR post-processing methods showed similar prognostic value and can be used for LVEF assessment. LVEF and indexed LV mass are independent predictors for appropriate ICD shocks and all-cause mortality in the ICD population.

Structural and Physiological Imaging to Predict the Risk of Lethal Ventricular Arrhythmias and Sudden Death

Identifying patients at risk of sudden cardiac death remains a major challenge in cardiovascular medicine. Advances in cardiovascular imaging have identified several anatomic and functional variables that can be quantified as continuous variables to predict the risk of developing lethal ventricular tachyarrhythmias in patients with depressed left ventricular (LV) systolic function. Some, such as LV mass, volume, and the dyssynchrony of contraction, can be derived from currently available echocardiographic and nuclear imaging modalities. Others require advanced cardiac imaging modalities with quantification of myocardial scar with gadolinium-enhanced cardiac magnetic resonance and myocardial sympathetic denervation using norepinephrine analogs and positron emission tomography or single-photon emission computed tomography offering the most promise. There is an immediate need to develop a sequential cost-effective approach that capitalizes on readily available clinical information complemented with advanced imaging modalities in selected patients to improve risk stratification for arrhythmic death beyond LV ejection fraction.

Application of data mining in a cohort of Italian subjects undergoing myocardial perfusion imaging at an academic medical center

INTRODUCTION

Coronary artery disease (CAD) is still one of the primary causes of death in the developed countries. Stress single-photon emission computed tomography is used to evaluate myocardial perfusion and ventricular function in patients with suspected or known CAD. This study sought to test data mining and machine learning tools and to compare some supervised learning algorithms in a large cohort of Italian subjects with suspected or known CAD who underwent stress myocardial perfusion imaging.

METHODS

The dataset consisted of 10,265 patients with suspected or known CAD. The analysis was conducted using Knime analytics platform in order to implement Random Forests, C4.5, Gradient boosted tree, Naïve Bayes, and K nearest neighbor (KNN) after a procedure of features filtering. K-fold cross-validation was employed.

RESULTS

Accuracy, error, precision, recall, and specificity were computed through the above-mentioned algorithms. Random Forests and gradients boosted trees obtained the highest accuracy (>95%), while it was comprised between 83% and 88%. The highest value for sensitivity and specificity was obtained by C4.5 (99.3%) and by Gradient boosted tree (96.9%). Naïve Bayes had the lowest precision (70.9%) and specificity (72.0%), KNN the lowest recall and sensitivity (79.2%).

CONCLUSIONS

The high scores obtained by the implementation of the algorithms suggests health facilities consider the idea of including services of advanced data analysis to help clinicians in decision-making. Similar applications of this kind of study in other contexts could support this idea.

Left ventricular eccentricity index measured with SPECT myocardial perfusion imaging: An additional parameter of adverse cardiac remodeling

BACKGROUND

Single-photon emission computed-tomography (SPECT) allows the quantification of LV eccentricity index (EI), a measure of cardiac remodeling. We sought to evaluate the feasibility of EI measurement with SPECT myocardial perfusion imaging and its interactions with relevant LV functional and structural parameters.

METHODS AND RESULTS

Four-hundred and fifty-six patients underwent myocardial perfusion imaging on a Cadmium-Zinc-Telluride (CZT) camera. The summed rest, stress, and difference scores were calculated. From rest images, the LV end-diastolic (EDV) and end-systolic volumes, ejection fraction (EF), and peak filling rate (PFR) were calculated. In every patient, the EI, ranging from 0 (sphere) to 1 (line), was computed using a dedicated software (QGS/QPS; Cedars-Sinai Medical Center). Three-hundred and thirty-eight/456 (74%) patients showed a normal EF (>50%), while 26% had LV systolic dysfunction. The EI was computed from CZT images with excellent reproducibility (interclass correlation coefficient: 0.99, 95% CI 0.98-0.99). More impaired EI values correlated with the presence of a more abnormal LV perfusion (P < .001), function (EF and PFR, P < .001), and structure (EDV, P < .001). On multivariate analysis, higher EDV (P < .001) and depressed EF (P = .014) values were independent predictors of abnormal EI.

CONCLUSIONS

The evaluation of LV eccentricity is feasible on gated CZT images. Abnormal EI associates with significant cardiac structural and functional abnormalities.

Circulating miRNAs and Risk of Sudden Death in Patients With Coronary Heart Disease

OBJECTIVES

This study evaluated whether plasma miRNAs were specifically associated with sudden cardiac and/or arrhythmic death (SCD) in a cohort of patients with coronary heart disease (CHD), most of whom were without primary prevention implantable cardioverter-defibrillators.

BACKGROUND

Novel biomarkers for sudden death risk stratification are needed in patients with CHD to more precisely target preventive therapies, such as implantable cardioverter-defibrillators. miRNAs have been implicated in regulating inflammation and cardiac fibrosis in cells, and plasma miRNAs have been shown to predict cardiovascular death in patients with CHD.

METHODS

We performed a nested case control study within a multicenter cohort of 5,956 patients with CHD followed prospectively for SCD. Plasma levels of 18 candidate miRNAs previously associated with cardiac remodeling were measured in 129 SCD cases and 258 control subjects matched on age, sex, race, and left ventricular ejection fraction.

RESULTS

miR-150-5p, miR-29a-3p, and miR-30a-5p were associated with increased SCD risk (odds ratios and 95% confidence intervals: 2.03 [1.12 to 3.67]; p = 0.02; 1.93 [1.07 to 3.50]; p = 0.02; 0.55 [0.31 to 0.97]; p = 0.04, respectively, for third vs. first tertile miRNA level). Unfavorable levels of all 3 miRNAs was associated with a 4.8-fold increased SCD risk (1.59 to 14.51; p = 0.006). A bioinformatics-based approach predicted miR-150-5p, miR-29a-3p, and miR-30a-5p to be involved in apoptosis, fibrosis, and inflammation.

CONCLUSIONS

These findings suggest that plasma miRNAs may regulate pathways important for remodeling and may be useful in identifying patients with CHD at increased risk of SCD.

Added prognostic value of left ventricular shape by gated SPECT imaging in patients with suspected coronary artery disease and normal myocardial perfusion

BACKGROUND

Left ventricular (LV) remodeling is associated with adverse cardiovascular events. We evaluated the added prognostic value of LV shape index (SI) assessed by gated single-photon emission tomography (SPECT) in patients without known coronary artery disease (CAD).

METHODS AND RESULTS

We studied 674 patients with normal myocardial perfusion and normal LV ejection fraction (EF) on stress gated SPECT imaging. An automated software program was used to calculate end-diastolic and end-systolic LVSI. An LVSI ≤ 0.54 at end-systole was considered normal. Follow-up was 96% complete with a median follow-up of 37 months. During follow-up, 25 events occurred (3.8% cumulative event rate). Event-free survival was lower in patients with abnormal end-systolic LVSI (P < .001). Age (P = .021), diabetes (P = .048), and end-systolic LVSI (P < .001) were independent predictors of events. LVSI added prognostic information increasing the global chi-square of the model including age and diabetes from 15.15 to 25.97 (P < .001). The effect of diabetes on hazard ratio increased with increasing values of end-systolic LVSI. The probability of events at 48 months predicted by Weibull analysis progressively increased with increasing values of end-systolic LVSI and was higher in patients with diabetes as compared to those without. Decision curve analyses indicate that the model including end-systolic LVSI resulted in an increased net benefit between 5% and 30% threshold probability, indicating superior estimation of outcomes at low threshold probability levels.

CONCLUSIONS

The evaluation of LVSI may identify patients with early-stage LV remodeling and at higher risk of adverse cardiac events, even in the presence of normal myocardial perfusion.

Plasmatic Klotho and FGF23 Levels as Biomarkers of CKD-Associated Cardiac Disease in Type 2 Diabetic Patients

BACKGROUND

Research over the past decade has focused on the role of Klotho as a cardio protective agent that prevents the effects of aging on the heart and reduces the burden of cardiovascular disease CVD. The role of the interaction between fibroblast growth factor 23-(FGF-23)/Klotho in Klotho-mediated actions is still under debate. The main objective was to ascertain the potential use of plasmatic Klotho and FGF23 as markers for CKD-associated cardiac disease and mortality.

METHODS

This was a prospective analysis conducted in an outpatient diabetic nephropathy clinic, enrolling 107 diabetic patients with stage 2⁻3 CKD. Patients were divided into three groups according to their left ventricular mass index and relative wall thickness.

RESULTS

Multinomial regression analysis demonstrated that low Klotho and higher FGF-23 levels were linked to a greater risk of concentric hypertrophy. In the generalized linear model (GLM), Klotho, FGF-23 and cardiac geometry groups were statistically significant as independent variables of cardiovascular hospitalization (p = 0.007). According to the Cox regression model, fatal cardiovascular events were associated with the following cardiac geometric classifications; eccentric hypertrophy (p = 0.050); concentric hypertrophy (p = 0.041), and serum phosphate ≥ 3.6 mg/dL (p = 0.025), FGF-23 ≥ 168 (p = 0.0149), α-klotho < 313 (p = 0.044).

CONCLUSIONS

In our population, Klotho and FGF23 are associated with cardiovascular risk in the early stages of CKD.

Stress-induced alteration of left ventricular eccentricity: An additional marker of multivessel CAD

BACKGROUND

Abnormal left ventricular (LV) eccentricity index (EI) is a marker of adverse cardiac remodeling. However, the interaction between stress-induced alterations of EI and major cardiac parameters has not been explored. We sought to evaluate the relationship between LV EI and coronary artery disease (CAD) burden in patients submitted to myocardial perfusion imaging (MPI).

METHODS AND RESULTS

Three-hundred and forty-three patients underwent MPI and coronary angiography. LV ejection fraction (EF) and EI were computed from gated stress images as measures of stress-induced functional impairment. One-hundred and thirty-six (40%), 122 (35%), and 85 (25%) patients had normal coronary arteries, single-vessel CAD, and multivessel CAD, respectively. Post-stress EI was lower in patients with multivessel CAD than in those with normal coronary arteries and single-vessel CAD (P = 0.001). This relationship was confirmed only in patients undergoing exercise stress test, where a lower post-stress EI predicted the presence of multivessel CAD (P = 0.039).

CONCLUSIONS

Post-stress alterations of LV EI on MPI may unmask the presence of multivessel CAD.