Terminal QRS Distortion in ST Elevation Myocardial Infarction as a Prediction of Mortality: Systematic Review and Meta-Analysis.

BACKGROUND: Terminal QRS distortion reflects advanced stage and large myocardial infarction predisposing the heart to adverse outcomes. Recent studies suggest that terminal QRS distortion is associated with morbidity and mortality in ST elevation myocardial infarction (STEMI). However, a systematic review and meta-analysis of the literature have not been done. OBJECTIVE: We assessed the association between terminal QRS distortion in patients with STEMI and mortality by a systematic review of the literature and a meta-analysis. METHODS: We comprehensively searched the databases of MEDLINE and EMBASE from inception to September 2017. Included studies were published prospective or retrospective cohort studies that compared all-cause mortality in subjects with STEMI with QRS distortion versus those without QRS distortion. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals. RESULTS: Fifteen studies from January 1993 to May 2015 were included in this meta-analysis involving 7,479 subjects with STEMI (2,906 QRS distortion and 4,573 non-QRS distortion). QRS distortion was associated with increased mortality (pooled risk ratio = 1.81, 95% confidence interval: 1.37-2.40, p < 0.000, I2 = 41.6%). Considering the introduction of clopidogrel in 2004, we performed subgroup analyses before and after 2004, and the associated with higher mortality was still present (before 2004, RR 1.75, 95% CI 1.08-2.82, p = 0.022, I2 = 66.1%; after 2004, RR 1.96, 95% CI 1.44-2.65, p < 0.001, I2 = 0%). CONCLUSIONS: Terminal QRS distortion increased all-cause mortality by 81%. Our study suggests that terminal QRS distortion is an important tool to assess the risk in patients with STEMI.

The prognostic value of the combined use of QRS distortion and fragmented QRS in patients with acute STEMI undergoing primary percutaneous coronary intervention.

BACKGROUND: No study has investigated the prognostic importance of the combined use of QRS distortion and fragmented QRS (fQRS) for risk stratification in acute ST segment elevation myocardial infarction (STEMI). OBJECTIVE: To determine the prognostic value of the combined use of QRS distortion and fQRS in patients with acute STEMI undergoing primary percutaneous coronary intervention (pPCI). METHODS: A total of 454 patients with first STEMI who underwent pPCI were included in this study. Patients were categorized into three groups according to the presence of QRS distortion and fQRS on admission electrocardiography. Group I was defined as fQRS (-) and QRS distortion (-), group 2 was defined as fQRS (+) and QRS distortion (-), or fQRS (-) and QRS distortion (+), and group 3 was defined as both fQRS (+) and QRS distortion (+). RESULTS: Patients in group III had a significantly higher in-hospital mortality rate compared with patients in groups I and II. These patients also had lower left ventricular ejection fraction and ST resolution ratios, higher maximum troponin, and higher frequency of three-vessel disease. Multivariate analysis indicated that group III (OR: 8.84, 95% CI: 2.73-28.62, p<0.001) was an independent predictors of in-hospital mortality. CONCLUSION: The combined use of QRS distortion and fQRS provides additional prognostic value compared with the presence of QRS distortion or fQRS alone for early risk stratification in patients with STEMI treated with pPCI.

The relationship between terminal QRS distortion on initial ECG and final infarct size at 4months in conventional ST- segment elevation myocardial infarct patients.

BACKGROUND: In the Sclarovsky-Birnbaum Ischemia Severity Grading System for patients with ST-segment elevation myocardial infarction (STEMI), "Terminal QRS distortion" is considered as "Grade III". This evidence for most severe ischemia is associated with cardiovascular magnetic resonance imaging (CMR) markers of myocardial damage in the subacute phase. Our aim was to assess whether terminal QRS distortions on the initial electrocardiogram (ECG) is predictive for infarct size (IS) and left ventricular ejection fraction (LVEF) at 4months in anterior versus infarct locations. METHODS: Patient data of the HEBE, GIPS III and MAST, were pooled. ECGs of 411 STEMI patients were classified as absence (Grade II) or presence (Grade III) of terminal QRS distortion according to Sclarovsky-Birnbaum grading. CMR was performed at approximately 4months and included IS and LVEF. RESULTS: Grade III ischemia was present in 142 of 411 (35%) patients and was more frequently observed with inferior STEMI (P=0.01). In the total cohort and in anterior STEMI, no difference in LVEF or IS was observed between the two Grades. Whereas, in inferior STEMI Grade III was associated with a larger IS (P<0.01) and also, a trend towards a lower LVEF was observed (P=0.09). CONCLUSION: In inferior STEMI, terminal QRS distortion on the initial ECG is associated with a larger IS at approximately 4months, and can be used to identify a high-risk population in the acute phase. Also, a Grade III was associated with a trend towards a lower LVEF.

QRS broadening due to terminal distortion is associated with the size of myocardial injury in experimental myocardial infarction.

INTRODUCTION: Not only repolarization, but also depolarization ECG indexes reflect the progression of ischemic injury. The aim was to assess the QRS duration and morphology dynamics during the prolonged coronary occlusion and their association with the myocardial area at risk (MaR) and final infarct size (IS). METHODS: In pigs, myocardial infarction was induced by inflation of an angioplasty balloon in the left descending artery (LAD), and ECG was continuously recorded. QRS duration was calculated on a beat-to-beat basis during the occlusion period. Single photon emission computed tomography (SPECT) was performed for the assessment of MaR, and IS was assessed by magnetic resonance imaging (MRI). RESULTS: All animals developed an anteroseptal infarction with MaR 40±9% and IS 23±7%. Two peaks of QRS widening were found in all animals: the early peak immediately after LAD occlusion and the late one 17.7±4.1min later. No association was found between MaR and IS and either QRS width or the degree of QRS widening at the early peak. QRS duration on the late peak correlated with both MaR (r=0.61; p=0.007) and IS (r=0.55; p=0.018). CONCLUSION: The QRS widening at the late peak, but not at the early peak, is associated with the size of myocardial injury, suggesting different underlying mechanisms.

The Predictive Value of Fragmented QRS and QRS Distortion for High-Risk Patients with STEMI and for the Reperfusion Success.

BACKGROUND: QRS fragmentation (fQRS) and QRS distortion were separately shown to be related to increased cardiovascular mortality and morbidity. To our knowledge, no study so far evaluated both parameters together in ST segment elevation myocardial infarction (STEMI). The main goal of our study is to find out if fQRS and QRS distortion can help us to determine high-risk STEMI patients, and the success of reperfusion. METHODS: Two hundred forty-eight eligible patients with acute STEMI that underwent coronary angiography consecutively between January 1, 2009, and July 1, 2011, were enrolled in this study. Twelve-lead electrocardiography (ECG) of the patients taken in the first 48 hours were analyzed. Patients with fQRS formed group 1, without fQRS formed group 2; with QRS distortion formed group 3, and without QRS distortion formed group 4. RESULTS: Group 1 have lower left ventricular ejection fraction (LVEF; P < 0.001), higher maximum troponin levels (P < 0.001), lower ST segment resolution (P < 0.001), more frequent proximal lesions (P < 0.001) when compared to group 2. Similar findings were observed in group 3 in comparison to group 4. Group 1 had also more frequent three vessels disease (P < 0.001), and higher rates of failed thrombolysis (P < 0.001). In-hospital mortality was found to be higher in group 1 and group 3. CONCLUSION: fQRS and QRS distortion may be useful for identifying patients at higher cardiac risk. fQRS can foresee thrombolytic therapy failure and three vessels disease whereas QRS distortion does not possess such quality. These findings may guide the physician deciding initial treatment modality in STEMI.

Pre-hospital evaluation of electrocardiographic grade 3 ischemia predicts infarct progression and final infarct size in ST elevation myocardial infarction patients treated with primary percutaneous coronary intervention.

BACKGROUND: In STEMI, grade-3 ischemia (G3) on admission ECG predicts larger infarct size (IS) than grade-2 (G2). We evaluated whether pre-hospital G3 and its temporal behavior are associated with IS and salvage after pPCI. METHODS: In 401 STEMI patients, pre-hospital and pre-PCI ECGs were classified as G3 or G2. IS was assessed by single-photon emission computed tomography (SPECT) at 30days. In 245 patients, pre-PCI SPECT was available to determine myocardium at risk (MaR). RESULTS: G3 criteria were met by 88, and G2 by 313 patients. G3 was independently associated with IS (p=0.006). With ST resolution (STR) group as a reference, G2->G2, G2->G3 and G3->G3 were associated with larger IS (B=4.4, p=0.004; B=5.4, p=0.01; B=10.2, p<0.001, respectively), whereas G3->G2 was not. Salvage was similar between G3 and G2 on pre-hospital ECG if treated early, however lower for G3 when treated later (>2.5h); 48% (35-78) vs 62% (40-87); p=0.04. CONCLUSION: Development or persistence of G3 is associated with larger IS and less salvage, but decreasing grade G3->G2 was not.

Early/Subtle Electrocardiography Features of Acute Coronary Syndrome and ST-Segment Elevation Myocardial Infarction.

Chest pain is one of the most common presenting complaints in the emergency department. Interpreting a 12-lead electrocardiography (ECG) for evidence of ischemia is always challenging. Frank ECG changes such as ST-segment elevation and ST-segment depression can be easily identified by emergency physicians. However, identifying subtle or early features of ACS in the 12-lead ECG is essential in preventing significant mortality and morbidity from ACS. In the following case series, we describe five of the subtle/early ECG changes of ACS, namely (1) T-wave inversion in lead aVL; (2) terminal QRS distortion; (3) hyperacute T-waves; (4) negative U-waves in precordial leads; and (5) loss of precordial T-wave balance. In all these cases, the initial 12-lead ECG showed only subtle/early ECG changes which were followed up with serial ECGs which progressed to STEMI.

Prognostic significance of QRS distortion and frontal QRS-T angle in patients with ST-elevation myocardial infarction.

BACKGROUND: QRS distortion (G3I) and frontal QRS-T angle (fQRS-T angle) are both electrocardiographic (ECG) signs of ongoing ischemia and depolarization-repolarization heterogeneity, which always occur in patients with ST-segment elevation acute myocardial infarction (STEMI). METHODS: We retrospectively collected 592 STEMI patients who underwent coronary angiography and follow-up for 42 months. 1. We divided the patients into two groups according to whether they had G3I on admission, compared the differences in examination data and endpoint events between these two groups. 2. Group patients according to whether the endpoint events happened in hospital, at 12 and 42 months, compare whether there is a difference in fQRS-T angle at the same time point, and find out the predictive cutoff value of all-cause death. 3. Combined G3I and fQRS-T angle together to enhance the predictive value. RESULTS: G3I and fQRS-T angle are both independent risk factors for all-cause death in STEMI patients within 12 months (G3I P = 0.014, fQRS-T angle P < 0.001) and within 42 months (P < 0.001). The cutoff values of fQRS-T angle for predicting all-cause death are 66.5° at 12 months and 90.5° at 42 months. When G3I and fQRS-T angle are combined used to predict the mortality, the specificity is significantly improved, but the sensitivity decreased. CONCLUSIONS: G3I and fQRS-T angles are valuable in the prognostic assessment of STEMI patients, especially when combined. These findings help clinicians to identify high-risk patients early for more aggressive treatment.

QRS distortion in pre-reperfusion electrocardiogram is a bedside predictor of large myocardium at risk and infarct size (a METOCARD-CNIC trial substudy).

BACKGROUND: QRS distortion is an electrocardiographic (ECG) sign of severe ongoing ischemia in the setting of ST-segment elevation acute myocardial infarction (STEMI). We sought to evaluate the association between the degree of QRS distortion and myocardium at risk and final infarct size, measured by cardiac magnetic resonance (CMR). METHODS: A total of 174 patients with a first anterior STEMI reperfused by primary angioplasty were prospectively recruited. Pre-reperfusion ECG was used to divide the study population into three groups according to the absence of QRS distortion (D0) or its presence in a single lead (D1) or in 2 or more contiguous leads (D2+). Myocardium at risk and infarct size were determined by CMR one week after STEMI. Multiple regression analysis was used to study the association of QRS distortion with myocardium at risk and infarct size, with adjustment for relevant clinical and ECG variables. RESULTS: 101 patients (58%) were in group D0, 30 (17%) in group D1, and 43 (25%) in group D2+. Compared with group D0, presence of QRS distortion (groups D2+ and D1) was associated with a significantly adjusted larger extent of myocardium at risk (group D2+: absolute increase 10.4%, 95% CI 6.1-14.8%, p<0.001; group D1: absolute increase 3.3%, 95% CI 1.3-7.9%, p=0.157) and larger infarct size (group D2+: absolute increase 10.1%, 95% CI 5.5-14.7%, p<0.001; group D1: absolute increase 4.9%, 95% CI 0.08-9.8%, p=0.046). CONCLUSIONS: Distortion in the terminal portion of the QRS complex on pre-reperfusion ECG in two or more leads is independently associated with larger myocardium at risk and infarct size in the setting of primary angioplasty-reperfused anterior STEMI. QRS distortion in only one lead is independently associated with larger infarct size in this setting. Our findings suggest that QRS distortion analysis could be included in risk-stratification of patients presenting with anterior STEMI.

Significance of terminal QRS distortion on the electrocardiogram in acute inferior myocardial infarction / 中国医师进修杂志

Objective To investigate whether terminal QRS distortion on the electrocardiogram in acute inferior myocardial infarction could be as a standard for the infarct-related artery,through comparing to coronary angiography.Methods Fifty-seven patients with acute inferior myocardial infarction were enrolled,among which,the right coronary artery (RCA) occlusion (RCA occlusion group) was present in 29 cases,and left circumflex coronary artery (LCX) occlusion (LCX occlusion group) was in 28 cases.The changes of electrocardiogram was analyzed in 12 hours after the acute episode.Results The incidence of terminal QRS distortion in leads Ⅱ,Ⅲ,aVF in RCA occlusion group was 44.8％(13/29) and 39.3％(11/28)in LCX occlusion group,and there was no significant difference (P ＞ 0.05).The incidence of terminal QRS distortion in leads V4R-V5R in RCA occlusion group was 17.2％(5/29) and 7.1％(2/28) in LCX occlusion group,and there was no significant difference (P ＞ 0.05).The incidence of terminal QRS distortion in leads V7-V9 in RCA occlusion group was 6.9％(2/29),which was lower than that in LCX occlusion group[53.6％(15/28)],and there was significant difference (P ＜ 0.05).For identifying LCX as the infarct-related artery of acute inferior myocardial infarction,the sensitivity,specificity,positive and negative value in terminal QRS distortion in leads V7-V9 were 53.6％ (15/28),93.1％ (27/29),88.2％ (15/17),67.5％ (27/40).The area under curve of terminal QRS distortion in leads V7-V9 in identifying LCX as the infarct-related artery of acute inferior myocardial infarction was 0.733 (95％ CI 0.599-0.868).Conclusion Terminal QRS distortion in leads V7-V9 may be of diagnostic value in identifying the infarct-related artery in acute inferior myocardial infarction.

Terminal QRS Complex Distortion on the Admission Electrocardiogram in Anterior Acute Myocardial Infarction and Association with Residual Flow and Infarct Size after Primary Angioplasty

BACKGROUND: Terminal QRS complex distortion on admission is a simple and reliable predictor of infarct size in patients with acute myocardial infarction (AMI). It is uncertain, however, whether this reflects reduced myocardial perfusion of the infarct area and a larger area of the myocardium at risk. This study was conducted to investigate whether terminal QRS distortion complex on admission is a reliable predictor of reduced residual flow and a larger area of the myocardium at risk compared to patients who are admitted without a terminal QRS distortion. METHODS: We evaluated the relationship between terminal QRS complex distortion and residual flow to the infarct zone and risk area in 46 anterior AMI patients undergoing primary angioplasty. 99mTc-sestamibi imaging was performed at baseline and 5-9 days after angioplasty. The study population was divided into those with (Group I, n=16) and without (Group II, n=30) terminal QRS complex distortion. RESULTS: Baseline characteristics were similar between the two groups. The area of the myocardium at risk was higher in Group I (59.9 +/- 15.3%) than in Group II (48.6 +/- 13.7%, p< 0.05; mean+SD) while the nadir measurement of the residual flow was lower in Group I (0.10 +/- 0.07) than in Group II (0.16 +/- 0.09, p< 0.05). Although the final infarct size was significantly higher in Group I (40.8 +/- 17.2%) than in Group II (27.1 +/- 18.1%, p< 0.05), the myocardial salvage index did not differ significantly between the two groups. CONCLUSION: Terminal QRS complex distortion seems to be associated with less residual flow to the infarct zone, a larger risk area and greater infarct size in patients with anterior AMI.