Persistent T-wave inversion predicts myocardial damage after ST-elevation myocardial infarction

Cardiac conduction system regeneration prevents arrhythmias after myocardial infarction

Arrhythmias are a hallmark of myocardial infarction (MI) and increase patient mortality. How insult to the cardiac conduction system causes arrhythmias following MI is poorly understood. Here, we demonstrate conduction system restoration during neonatal mouse heart regeneration versus pathological remodeling at non-regenerative stages. Tissue-cleared whole-organ imaging identified disorganized bundling of conduction fibers after MI and global His-Purkinje disruption. Single-cell RNA sequencing (scRNA-seq) revealed specific molecular changes to regenerate the conduction network versus aberrant electrical alterations during fibrotic repair. This manifested functionally as a transition from normal rhythm to pathological conduction delay beyond the regenerative window. Modeling in the infarcted human heart implicated the non-regenerative phenotype as causative for heart block, as observed in patients. These findings elucidate the mechanisms underpinning conduction system regeneration and reveal how MI-induced damage elicits clinical arrhythmogenesis.

Mechanisms and Implications of Electrical Heterogeneity in Cardiac Function in Ischemic Heart Disease

A healthy heart shows intrinsic electrical heterogeneities that play a significant role in cardiac activation and repolarization. However, cardiac diseases may perturb the baseline electrical properties of the healthy cardiac tissue, leading to increased arrhythmic risk and compromised cardiac functions. Moreover, biological variability among patients produces a wide range of clinical symptoms, which complicates the treatment and diagnosis of cardiac diseases. Ischemic heart disease is usually caused by a partial or complete blockage of a coronary artery. The onset of the disease begins with myocardial ischemia, which can develop into myocardial infarction if it persists for an extended period. The progressive regional tissue remodeling leads to increased electrical heterogeneities, with adverse consequences on arrhythmic risk, cardiac mechanics, and mortality. This review aims to summarize the key role of electrical heterogeneities in the heart on cardiac function and diseases. Ischemic heart disease has been chosen as an example to show how adverse electrical remodeling at different stages may lead to variable manifestations in patients. For this, we have reviewed the dynamic electrophysiological and structural remodeling from the onset of acute myocardial ischemia and reperfusion to acute and chronic stages post-myocardial infarction. The arrhythmic mechanisms, patient phenotypes, risk stratification at different stages, and patient management strategies are also discussed. Finally, we provide a brief review on how computational approaches incorporate human electrophysiological heterogeneity to facilitate basic and translational research.

The prognostic significance of Q waves and T wave inversions in the ECG of patients with STEMI: A substudy of the TOTAL trial

BACKGROUND

The prognostic significance of Q waves and T-wave inversions (TWI) combined and separately in STEMI patients undergoing primary PCI has not been well established in previous studies.

METHODS

We included 7,831 patients from the TOTAL trial and divided the patients into categories based on Q waves and TWIs in the presenting ECG. The primary outcome was a composite of cardiovascular death, recurrent myocardial infarction (MI), cardiogenic shock or new or worsening NYHA class IV heart failure within one year. The study evaluated the effect of Q waves and TWI on the risk of primary outcome and all-cause death, and whether patient benefit of aspiration thrombectomy differed between the ECG categories.

RESULTS

Patients with Q+TWI+ (Q wave and TWI) pattern had higher risk of primary outcome compared to patients with Q-TWI- pattern [33 (10.5%) vs. 221 (4.2%); adjusted hazard ratio (aHR) 2.10; 95% CI, 1.45-3.04; p<0.001] within 40-days' period. When analyzed separately, patients with Q waves had a higher risk for the primary outcome compared to patients with no Q waves in the first 40 days [aHR 1.80; 95% CI, 1.48-2.19; p<0.001] but there was no additive risk after 40 days. Patients with TWI had a higher risk for primary outcome only after 40 days when compared to patients with no TWI [aHR 1.63; 95% CI, 1.04-2.55; p=0.033]. There was a trend towards a benefit of thrombectomy in patients with the Q+TWI+ pattern.

CONCLUSIONS

Q waves and TWI combined (Q+TWI+ pattern) in the presenting ECG is associated with unfavourable outcome within 40-days. Q waves tend to affect short-term outcome, while TWI has more effect on long-term outcome.

Estimating the extent of myocardial damage in patients with STEMI using the DETERMINE score

Background

Recently, a simple ECG score (DETERMINE score) has been proposed for estimating myocardial scar in patients with ischaemic cardiomyopathy. We sought to evaluate the usefulness of the DETERMINE score for the assessment of myocardial infarct size (IS) as well as microvascular obstruction (MVO), in the setting of ST-elevation myocardial infarction (STEMI).

Methods

This observational study enrolled 423 patients with STEMI (median age 56, 17% women), revascularised by primary percutaneous coronary intervention (PCI). For evaluation of the DETERMINE and Selvester scoring system (an established but complex ECG score for IS estimation), ECG was conducted before discharge (median: 4 (IQR 2–6) days). Cardiac magnetic resonance (CMR) was conducted within a week after infarction for determination of IS and MVO.

Results

Median DETERMINE score of the overall cohort was 8 points (IQR 5–11). A higher DETERMINE score was significantly associated with a larger IS (21% vs 11% of left ventricular myocardial mass (LVMM), p<0.001) as well as larger MVO (1.2% vs 0.0% of LVMM, p<0.001). In linear and binary multivariable logistic regression analysis, the DETERMINE score remained independently associated with IS (OR 1.09, 95% CI 1.02 to 1.17, p=0.014) and MVO (OR 1.12, 95% CI 1.04 to 1.21, p=0.003), after adjustment for Selvester score and clinical indicators of IS (high-sensitivity cardiac troponin T, high-sensitivity C reactive protein, N-terminal pro-B-type natriuretic peptide, TIMI flow pre-interventional and post-interventional PCI, anterior infarct localisation).

Conclusions

In patients undergoing PCI for STEMI, the DETERMINE score provides an easy and inexpensive tool for appropriate estimation of infarct severity as determined by CMR.

The prognostic significance of T-wave inversion according to ECG lead group during long-term follow-up in the general population

Background

Inverted T waves in the electrocardiogram (ECG) have been associated with coronary heart disease (CHD) and mortality. The pathophysiology and prognostic significance of T‐wave inversion may differ between different anatomical lead groups, but scientific data related to this issue is scarce.

Methods

A representative sample of Finnish subjects (n = 6,354) aged over 30 years underwent a health examination including a 12‐lead ECG in the Health 2000 survey. ECGs with T‐wave inversions were divided into three anatomical lead groups (anterior, lateral, and inferior) and were compared to ECGs with no pathological T‐wave inversions in multivariable‐adjusted Fine–Gray and Cox regression hazard models using CHD and mortality as endpoints.

Results

The follow‐up for both CHD and mortality lasted approximately fifteen years (median value with interquartile ranges between 14.9 and 15.3). In multivariate‐adjusted models, anterior and lateral (but not inferior) T‐wave inversions associated with increased risk of CHD (HR: 2.37 [95% confidence interval 1.20–4.68] and 1.65 [1.27–2.15], respectively). In multivariable analyses, only lateral T‐wave inversions associated with increased risk of mortality in the entire study population (HR 1.51 [1.26–1.81]) as well as among individuals with no CHD at baseline (HR 1.59 [1.29–1.96]).

Conclusions

The prognostic information of inverted T waves differs between anatomical lead groups. T‐wave inversion in the anterior and lateral lead groups is independently associated with the risk of CHD, and lateral T‐wave inversion is also associated with increased risk of mortality. Inverted T wave in the inferior lead group proved to be a benign phenomenon.

The high-risk ECG pattern of ST-elevation myocardial infarction: A substudy of the randomized trial of primary PCI with or without routine manual thrombectomy (TOTAL trial)

BACKGROUND

Useful tools for risk assessment in patients with STEMI are needed. We evaluated the prognostic impact of the evolving myocardial infarction (EMI) and the preinfarction syndrome (PIS) ECG patterns and determined their correlation with angiographic findings and treatment strategy.

METHODS

This substudy of the randomized Trial of Routine Aspiration Thrombectomy with PCI versus PCI Alone in Patients with STEMI (TOTAL) included 7860 patients with STEMI and either the EMI or the PIS ECG pattern. The primary outcome was a composite of death from cardiovascular causes, recurrent MI, cardiogenic shock, or New York Heart Association (NYHA) class IV heart failure within one year.

RESULTS

The primary outcome occurred in 271 of 2618 patients (10.4%) in the EMI group vs. 322 of 5242 patients (6.1%) in the PIS group [AdjustedHR, 1.54; 95% CI, 1.30 to 1.82; p < .001]. The primary outcome occurred in the thrombectomy and PCI alone groups in 131 of 1306 (10.0%) and 140 of 1312 (10.7%) patients with EMI [HR 0.94; 95% CI, 0.74-1.19] and 162 of 2633 (6.2%) and 160 of 2609 (6.1%) patients with PIS [HR 1.00; 95% CI, 0.81-1.25], respectively (p_interaction = 0.679).

CONCLUSIONS

Patients with the EMI ECG pattern proved to have an increased rate of the primary outcome within one year compared to the PIS pattern. Routine manual thrombectomy did not reduce the risk of primary outcome within the different dynamic ECG patterns. The PIS/EMI dynamic ECG classification could help to triage patients in case of simultaneous STEMI patients with immediate need for pPCI.

Aortic Stiffness and Infarct Healing in Survivors of Acute ST-Segment-Elevation Myocardial Infarction

Background

In survivors of acute ST‐segment–elevation myocardial infarction (STEMI), increased aortic stiffness is associated with worse clinical outcome; however, the underlying pathomechanisms are incompletely understood. We aimed to investigate associations between aortic stiffness and infarct healing using comprehensive cardiac magnetic resonance imaging in patients with acute STEMI.

Methods and Results

This was a prospective observational study including 103 consecutive STEMI patients treated with primary percutaneous coronary intervention. Pulse wave velocity (PWV), the reference standard for aortic stiffness assessment, was determined by a validated phase‐contrast cardiac magnetic resonance imaging protocol within the first week after STEMI. Infarct healing, defined as relative infarct size reduction from baseline to 4 months post‐STEMI, was determined using late gadolinium‐enhanced cardiac magnetic resonance. Median infarct size significantly decreased from 17% of left ventricular mass (interquartile range 9% to 28%) at baseline to 12% (6% to 17%) at 4‐month follow‐up (P<0.001). Relative infarct size reduction was 36% (interquartile range 15% to 52%). Patients with a reduction >36% were younger (P=0.01) and had lower baseline NT‐proBNP (N‐terminal pro–B‐type natriuretic peptide) concentrations (P=0.047) and aortic PWV values (P=0.003). In a continuous (odds ratio 0.64 [95% CI, 0.49–0.84]; P=0.001) as well as categorical (PWV <7 m/s; odds ratio 4.80 [95% CI, 1.89–12.20]; P=0.001) multivariable logistic regression model, the relation between aortic PWV and relative infarct size reduction remained significant after adjustment for baseline infarct size, age, NT‐proBNP, and C‐reactive protein.

Conclusions

Aortic PWV independently predicted infarct size reduction as assessed by cardiac magnetic resonance, revealing a novel pathophysiological link between aortic stiffness and adverse infarct healing during the early phase after STEMI treated with contemporary primary percutaneous coronary intervention.

Complete versus simplified Selvester QRS score for infarct severity assessment in ST-elevation myocardial infarction

Background

Complete and simplified Selvester QRS score have been proposed as valuable clinical tool for estimating myocardial damage in patients with ST-elevation myocardial infarction (STEMI). We sought to comprehensively compare both scoring systems for the prediction of myocardial and microvascular injury assessed by cardiac magnetic resonance (CMR) imaging in patients with acute STEMI.

Methods

In this prospective observational study, 201 revascularized STEMI patients were included. Electrocardiography was conducted at a median of 2 (interquartile range 1–4) days after the index event to evaluate the complete and simplified QRS scores. CMR was performed within 1 week and 4 months thereafter to determine acute and chronic infarct size (IS) as well as microvascular obstruction (MVO).

Results

Complete and simplified QRS score showed comparable predictive value for acute (area under the curve (AUC) = 0.64 vs. 0.67) and chronic IS (AUC = 0.63 vs. 0.68) as well as for MVO (AUC = 0.64 vs. 0.66). Peak high sensitivity cardiac troponin T (hs-cTnT) showed an AUC of 0.88 for acute IS and 0.91 for chronic IS, respectively. For the prediction of MVO, peak hs-cTnT represented an AUC of 0.81.

Conclusions

In reperfused STEMI, complete and simplified QRS score displayed comparable value for the prediction of acute and chronic myocardial as well as microvascular damage. However, both QRS scoring systems provided inferior predictive validity, compared to peak hs-cTnT, the clinical reference method for IS estimation.

Baseline LV ejection fraction by cardiac magnetic resonance and 2D echocardiography after ST-elevation myocardial infarction - influence of infarct location and prognostic impact

Objectives

The comparability of left ventricular ejection fraction (LVEF) measurements by cardiac magnetic resonance (CMR) and 2D echocardiography (2DE) early after ST-elevation myocardial infarction (STEMI) remains unclear.

Methods

In this study, LVEF measured by CMR and 2DE (Simpson’s method) were compared in 221 patients after STEMI treated by primary percutaneous coronary intervention. 2DE image quality was systematically assessed and studies reported by an accredited examiner. Intermodality agreement was assessed by the Bland–Altman method. Major adverse cardiac events (MACE) were defined as the composite of death, myocardial infarction or hospitalisation for heart failure. Patients were followed up for a median of 40.9 months (IQR 28.1–56).

Results

After non-anterior STEMI, LVEF measurements by 2DE (single and biplane) were consistently underestimated in comparison to CMR (CMR 55.7 ± 9.5% vs. 2DE-4CV 49 ± 8.2% (p = 0.06), 2DE-2CV 52 ± 8% (p < 0.001), 2DE-biplane 53.5 ± 7.1% (p = 0.01)). After anterior STEMI, there was no significant difference in LVEF measurements by 2DE and CMR with acceptable limits of agreement (CMR 49 ± 11% vs. 2DE-4CV 49 ± 8.2% (p = 0.8), 2DE-2CV 49 ± 9.2% (p = 0.9), 2DE-biplane 49.6 ± 8% (p = 0.5)). In total, 15% of patients experienced a MACE during follow-up. In multivariate Cox regression analysis, reduced LVEF (< 52%) as assessed by either 2DE or CMR was predictive of MACE (2DE HR = 2.57 (95% CI 1.1–6.2), p = 0.036; CMR HR = 2.51 (95% CI 1.1–5.7), p = 0.028).

Conclusions

At baseline after non-anterior STEMI, 2D echocardiography significantly underestimated LVEF in comparison to CMR, whereas after anterior infarction, measurements were within acceptable limits of agreement. Both imaging modalities offered similar prognostic values when a reduced LVEF < 52% was applied.

Key Points

• After non-anterior STEMI, 2D-echocardiography significantly underestimated LVEF compared with cardiac MRI

• An ejection fraction of < 52% in the acute post-infarct period by both 2D echocardiography and CMR offered similar prognostic values

Prognosis-based definition of left ventricular remodeling after ST-elevation myocardial infarction

Objectives

Cardiac magnetic resonance (CMR) is the gold-standard modality for the assessment of left ventricular (LV) remodeling in ST-elevation myocardial infarction (STEMI) patients. However, the commonly used remodeling criteria have never been validated for hard clinical events. We therefore aimed to define clear CMR criteria of LV remodeling following STEMI with proven prognostic impact.

Methods

This observational study included 224 patients suffering from acute STEMI. CMR was performed within 1 week and 4 months after infarction to evaluate different remodeling criteria including relative changes in LV end-diastolic volume (%∆LVEDV), end-systolic volume (%∆LVESV), ejection fraction (%∆LVEF), and myocardial mass (%∆LVMM). Primary endpoint was the occurrence of major adverse cardiovascular events (MACE) including all-cause death, re-infarction, stroke, and new congestive heart failure 24 months following STEMI. Secondary endpoint was defined as composite of primary endpoint and cardiovascular hospitalization. The Mann–Whitney U test was applied to assess differences in LV remodeling measures between patients with and without MACE. Values for the prediction of primary and secondary endpoints were assessed by c-statistics and Cox regression analysis.

Results

The incidence of MACE (n = 13, 6%) was associated with higher %∆LVEDV (p = 0.002) and %∆LVMM (p = 0.02), whereas %∆LVESV and %∆LVEF were not significantly related to MACE (p > 0.05). The area under the curve (AUC) for the prediction of MACE was 0.76 (95% confidence interval [CI], 0.65–0.87) for %∆LVEDV (optimal cut-off 10%) and 0.69 (95%CI, 0.52–0.85) for %∆LVMM (optimal cut-off 5%). From all remodeling criteria, %∆LVEDV ≥ 10% showed highest hazard ratio (8.68 [95%CI, 2.39–31.56]; p = 0.001) for MACE. Regarding secondary endpoint (n = 35, 16%), also %∆LVEDV with an optimal threshold of 10% emerged as strongest prognosticator (AUC 0.66; 95%CI, 0.56–0.75; p = 0.004).

Conclusions

Following revascularized STEMI, %∆LVEDV ≥ 10% showed strongest association with clinical outcome, suggesting this criterion as preferred CMR-based definition of post-STEMI LV remodeling.

Key Points

• CMR-determined %∆LVEDV and %∆LVMM were significantly associated with MACE following STEMI.

• Neither %∆LVESV nor %∆LVEF showed a significant relation to MACE.

• %∆LVEDV ≥ 10 was revealed as LV remodeling definition with highest prognostic validity.

Prognostic value of frontal QRS-T angle in patients undergoing myocardial revascularization or cardiac valve surgery

BACKGROUND

An abnormal frontal QRS-T angle (fQRSTa) is associated with increased risk of death in primary and secondary cardiovascular prevention. The aim of this study was to evaluate the fQRSTa prognostic role in patients undergoing myocardial revascularization and/or cardiac valve surgery.

METHODS

We enrolled and prospectively followed for 48 ± 26 months 939 subjects with available QRS and T axis data; mean age was 68 ± 12 years, 449 patients (48%) underwent myocardial revascularization, 333 (35%) cardiac valve surgery, 94 (10%) valve plus bypass graft surgery and 63 (7%) cardiac surgery for other cardiovascular (CV) diseases. The ECG variables were collected at the end of the cardiac rehabilitation program and fQRSTa was considered normal if <60°, abnormal if >120°, borderline otherwise. Endpoints were overall and CV mortality.

RESULTS

The fQRSTa was normal in 333 patients (36%), borderline in 285 (30%) and abnormal in 321 (34%). Overall (p = 0.012) and cardiovascular (p = 0.007) mortality were significantly higher in patients with abnormal fQRSTa even after adjusting separately for gender, PR-, QTc- intervals, presence of right or left bundle branch block and left atrial volume index. The predictive value was confirmed in patients with stable coronary artery disease (SCAD), not in patients with acute coronary syndrome or valve disease. SCAD patients with abnormal both fQRSTa and QRS axis had higher risk of overall (hazard ratio = 2.9, p < 0.0001) and CV (hazard ratio = 4.4, p < 0.0001) mortality compared with SCAD patients with normal fQRSTa, even after multivariate adjustment for age, gender, ECG intervals, left-ventricle ejection fraction and mass index.

CONCLUSIONS

In SCAD patients undergoing myocardial revascularization, abnormal fQRSTa is independent predictor of overall and CV mortality.