Prognostic significance of low QRS voltage on the admission electrocardiogram in acute coronary syndromes

Prevalence and clinical significance of low QRS voltages in healthy individuals, athletes, and patients with cardiomyopathy: implications for sports pre-participation cardiovascular screening

Low QRS voltages (LQRSV), defined as a QRS amplitude from peak to nadir < 0.5 mV in all limb leads, are an emerging diagnostic finding on the electrocardiogram (ECG). In healthy individuals and athletes, LQRSV are rare (2.2-4% of elite athletes, 0.5% of recreational athletes, and 0.3% of sedentary individuals). LQRSV athletes commonly show ventricular arrhythmias (VAs) on exercise, and up to 40% of those with LQRSV and VAs have late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). The prevalence of LQRSV in arrhythmogenic cardiomyopathy ranges from 17-40%, predicts left ventricular (LV) involvement, and is correlated with more extensive LGE replacement on CMR. In hypertrophic cardiomyopathy (HCM), LQRSV ranges from 0.7-11%. LQRSV-HCM patients have more segments with LGE, despite relatively smaller LV mass, suggesting a more advanced clinical stage and a worse prognosis. In dilated cardiomyopathy (DCM), LQRSV range from 6-7%, but may be higher (36%) in certain genetic forms of DCM. On a follow-up, LQRSV are independently associated with incident cardiac events, such as sudden death, sustained ventricular arrhythmia, or appropriate internal cardioverter defibrillator discharge. In cardiac amyloid, LQRSV range from 34-66% and demonstrate a negative prognostic value, with worse clinical outcomes regardless of underlying biologic, genetic, and clinical variables. In conclusion, LQRSV deserve careful consideration for exclusion of arrhythmogenic substrates in healthy individuals, athletes, and patients. While additional research is needed, it is reasonable that LQRSV should trigger clinical investigation to exclude underlying diseases at risk of life-threatening arrhythmias.

Beating the heart failure odds: long-term survival after myocardial ischemia in juvenile rainbow trout

Salmonid fish include some of the most valued cultured fish species worldwide. Unlike most other fish, the hearts of salmonids, including Atlantic salmon and rainbow trout, have a well-developed coronary circulation. Consequently, their hearts' reliance on oxygenation through coronary arteries leaves them prone to coronary lesions, believed to precipitate myocardial ischemia. Here, we mimicked such coronary lesions by subjecting groups of juvenile rainbow trout to coronary ligation, assessing histomorphological myocardial changes associated with ischemia and scarring in the context of cardiac arrhythmias using electrocardiography (ECG). Notable ECG changes resembling myocardial ischemia-like ECG in humans, such as atrioventricular blocks and abnormal ventricular depolarization (prolonged and fragmented QRS complex), as well as repolarization (long QT interval) patterns, were observed during the acute phase of myocardial ischemia. A remarkable 100% survival rate was observed among juvenile trout subjected to coronary ligation after 24 wk. Recovery from coronary ligation occurred through adaptive ventricular remodeling, coupled with a fast cardiac revascularization response. These findings carry significant implications for understanding the mechanisms governing cardiac health in salmonid fish, a family particularly susceptible to cardiac diseases. Furthermore, our results provide valuable insights into comparative studies on the evolution, pathophysiology, and ontogeny of vertebrate cardiac repair and restoration.NEW & NOTEWORTHY Juvenile rainbow trout exhibit a remarkable capacity to recover from cardiac injury caused by myocardial ischemia. Recovery from cardiac damage occurs through adaptive ventricular remodeling, coupled with a rapid cardiac revascularization response. These findings carry significant implications for understanding the mechanisms governing cardiac health within salmonid fishes, which are particularly susceptible to cardiac diseases.

Diagnostic test accuracy of life-threatening electrocardiographic findings (ST-elevation myocardial infarction equivalents) for acute coronary syndrome after out-of-hospital cardiac arrest without ST-segment elevation

AIM

Life-threatening electrocardiographic (ECG) findings aid in the diagnosis of acute coronary syndrome (ACS), which has not been well-evaluated in patients with out-of-hospital cardiac arrest (OHCA). This study aimed to evaluate the diagnostic test accuracy (DTA) of ST-elevation myocardial infarction (STEMI) equivalents following the return of spontaneous circulation (ROSC) in patients with OHCA to identify patients with ACS.

METHODS

Using the database of the Comprehensive Registry of In-Hospital Intensive Care for OHCA Survival study from 2012 to 2017, patients aged ≥18 years with non-traumatic OHCA and ventricular fibrillation or pulseless ventricular tachycardia on the arrival of emergency medical service personnel or arrival at the emergency department, who achieved ROSC, were included. Patients without ST-segment elevation or complete left bundle branch block on ECG and those who did not undergo ECG or coronary angiography, were excluded from the study. We evaluated the DTA of STEMI equivalents for the diagnosis of ACS: isolated T-wave inversion, ST-segment depression, Wellens' signs, and ST-segment elevation in lead aVR.

RESULTS

Isolated T-wave inversion and Wellens' signs had high specificity for ACS with 0.95 (95% confidence interval [CI], 0.87-0.99) and 0.92 (95% CI, 0.82-0.97), respectively, but their positive likelihood ratios were low, with a wide range of 95% CI: 1.89 (95% CI, 0.51-7.02) and 0.81 (95% CI, 0.25-2.68), respectively.

CONCLUSION

The DTA of STEMI equivalents for the diagnosis of ACS was low among patients with OHCA. Further investigation considering the measurement timing of the ECG after ROSC is required.

Prognostic value of initial QRS analysis in anterior STEMI: Correlation with left ventricular systolic dysfunction, serum biomarkers, and cardiac outcomes

BACKGROUND

The presence of pathologic Q waves on admission electrocardiogram (ECG) in patients with anterior ST-elevated myocardial infarction (STEMI) has been related to adverse cardiac outcomes. Our study evaluates the prognostic value of QRS complex and Q waves in patients with STEMI undergoing percutaneous coronary intervention.

METHODS

We prospectively analyzed the specific characteristics of QRS complex and pathologic Q waves on admission and on discharge ECG in 144 patients hospitalized for anterior STEMI. We correlated these findings with the development of left ventricular systolic dysfunction (LVSD), appearance of heart failure (HF) or death during follow-up, and levels of several biomarkers obtained 6 months after the index event.

RESULTS

Multivariate logistic regression analysis showed that QRS width (odds ratios [OR] 1.05, p = .001) on admission ECG and the sum of Q-wave depth (OR 1.06, p = .002) on discharge ECG were independent predictors of LVSD development. Moreover, QRS width on admission ECG was related to an increased risk of HF or death (OR 1.03, p = .026). Regarding biomarkers, QRS width on admission ECG revealed a statistically significant relationship with the levels of NT-pro-BNP at 6 months (0.29, p = .004); the sum of Q-wave depth (0.27, p = .012) and width (0.25, p = .021) on admission ECG was related to the higher levels of hs-cTnI; the sum of the voltages in precordial leads both on admission ECG (-0.26, p = .011) and discharge ECG (0.24, p = .046) was related to the lower levels of parathormone.

CONCLUSIONS

Assessment of QRS complex width and pathologic Q waves on admission and discharge ECGs aids in predicting long-term prognosis in patients with STEMI.

QRS complex characteristics and patient outcomes in out-of-hospital pulseless electrical activity cardiac arrest

BACKGROUND

Pulseless electrical activity (PEA) is increasingly observed in out-of-hospital cardiac arrest (OHCA), but outcomes are still poor. We aimed to assess the relationship between QRS characteristics and outcomes of patients with OHCA with initial PEA (OHCA-P).

METHODS

This prospective observational study included patients aged at least 18 years who developed OHCA-P between 1 January 2016 and 31 December 2018, and were enrolled in the Daegu Emergency Medical Services registry, South Korea. We performed multivariable logistic regression analyses to identify the associations between QRS characteristics and OHCA-P outcomes, in which QRS complexes were considered separately (model 1) and simultaneously (model 2). The primary outcome was survival to hospital discharge and the secondary outcome was a favourable neurological outcome.

RESULTS

Of the 3659 patients with OHCA, 576 were enrolled (median age 73 years; 334 men). A higher QRS amplitude was associated with survival to hospital discharge and a favourable neurological outcome in model 1 (adjusted OR (aOR) 1.077 and 1.106, respectively; 95% CI 1.021 to 0.136 and 1.029 to 1.190, respectively) and model 2 (aOR 1.084 and 1.123, respectively; 95% CI 1.026 to 1.145 and 1.036 to 1.216, respectively). A QRS width of <120 ms was associated with survival to hospital discharge and a favourable neurological outcome in model 1 (aOR 3.371 and 4.634, respectively; 95% CI 1.633 to 6.960 and 1.562 to 13.144, respectively) and model 2 (aOR 3.213 and 5.103, respectively; 95% CI 1.568 to 6.584 and 1.682 to 15.482, respectively). Survival to hospital discharge and neurological outcome were not associated with QRS frequency.

CONCLUSION

OHCA-P outcomes were better when the initial QRS complex showed a higher amplitude or narrower width.

Low QRS voltages in Olympic athletes: Prevalence and clinical correlates

BACKGROUND

Recently, novel interest in low QRS voltages was prompted by the observation that low QRS voltages are present in arrhythmogenic cardiomyopathy patients, even before occurrence of symptoms/events.

AIM

The purpose of this study was to assess prevalence and clinical correlates of low QRS voltages in Olympic athletes, evaluated and followed-up within our cardiovascular screening programme.

METHODS

Five hundred and sixteen athletes consecutively examined (2010-2011) were included in this study. A low QRS voltage was defined as amplitude of QRS <0.5 mV in limb and/or <1.0 mV in precordial leads. Cardiovascular evaluation included 12-lead and exercise electrocardiogram, echocardiography and, selectively, additional tests to confirm diagnosis. Athletes were followed-up for 5 ± 2 (1-9) years.

RESULTS

The majority of athletes (493; 96%) showed normal/increased R/S-wave voltages, but 23 (4%) had low QRS voltages. No differences were observed in low QRS voltage athletes compared to normal/increased QRS voltages for QRS duration, QTc and PR intervals, left ventricular cavity size and mass, or gender and sport participated. However, premature ventricular beats, occurred more frequently in low QRS voltages (39% vs 7%; p < 0.001), with patterns suggesting origin from left or right free wall. No diseases or events were registered in low QRS voltage athletes over the follow-up.

CONCLUSIONS

In Olympic athletes, the prevalence of low QRS voltages was 4%. Athletes with low QRS voltages did not differ from other athletes according to sport participated in or cardiac dimensions. However, more frequently (39% vs 7%) they showed premature ventricular beats, originating from either the left or right free ventricular wall. Therefore, long-term follow-up with serial clinical evaluations is needed in low QRS voltage athletes, in order to definitely clarify the clinical significance.

Low QRS Voltage on Presenting Electrocardiogram Predicts Multi-vessel Disease in Anterior ST-segment Elevation Myocardial Infarction

BACKGROUND

Low QRS voltage was reported to predict adverse outcomes in acute myocardial infarction in the pre-thrombolytic era. However, the association between low voltage and angiographic findings has not been fully addressed.

METHODS

We performed a retrospective analysis of patients with anterior ST-segment elevation myocardial infarction (STEMI). Low QRS voltage was defined as either peak to peak QRS complex voltage <1.0mV in all precordial leads or <0.5mV in all limb leads.

RESULTS

Among 190 patients, 37 patients (19%) had low voltage. Patients with low voltage had a higher rate of multi-vessel disease (MVD) (76% vs. 52%, p=0.01). Patients with low voltage were more likely to undergo coronary artery bypass grafting (CABG) during admission (11% vs. 2%, p=0.028). Low voltage was an independent predictor for MVD (OR 2.50; 95% CI 1.12 to 6.03; p=0.032).

CONCLUSION

Low QRS voltage was associated with MVD and in-hospital CABG in anterior STEMI.

ECG low QRS voltage and wide QRS complex predictive of centenarian 360-day mortality

We examined the electrocardiographic (ECG) findings of centenarians and associated them with >360-day survival. Physical and functional assessment, resting electrocardiogram and laboratory tests were performed on 86 study participants 101.9 ± 1.2 years old (mean ± SD) (70 women, 16 men) and followed for at least 360 days. Centenarian ECGs were assessed for left ventricular hypertrophy (LVH) according to the Romhilt-Estes score, Sokolow-Lyon criteria and Cornell voltage criteria which were positive for 12.8, 6.98, and 10.5 % of participants, respectively. Fifty-two study participants (60 %) survived ≥360 days. Multivariate logistic regression analysis revealed a negative relationship between 360-day survival and the following: R II <0.45 mV adjusted for CRP (odds ratio (OR) = 0.108, 95 % confidence interval (CI) = 0.034-0.341, P < .001), R aVF < 0.35 mV adjusted for CRP (OR = 0.151, 95 % CI = 0.039-0.584, P < .006), Sokolow-Lyon voltage <1.45 mV adjusted for CRP (OR = 0.178, 95 % CI = 0.064-0.492, P = .001), QRS ≥90 ms adjusted for CRP (OR = 0.375, 95 % CI = 0.144-0.975, P = .044), and Romhilt-Estes score ≥5 points adjusted for sex and Barthel Index (OR = 0.459, 95 % CI = 0.212-0.993, P = .048) in single variable ECG models. QRS voltage correlated positively with systolic and pulse pressure, serum vitamin B12 level, sodium, calcium, phosphorous, TIMP-1, and eGFR. QRS voltage correlated negatively with BMI, WHR, serum leptin, IL-6, TNF-α, and PAI-1 levels. QRS complex duration correlated positively with CRP; QTc correlated positively with TNF-α. Results suggest that Romhilt-Estes LVH criteria scores ≥5 points, low ECG QRS voltages (Sokolow-Lyon voltage <1.45 mV), and QRS complexes ≥90 ms are predictive of centenarian 360-day mortality.