A three-dimensional computed model of ST segment abnormality in type 1 Brugada Pattern: A key role of right ventricular outflow tract orientation?

Since its first description, Brugada Syndrome is characterized by definite ECG abnormalities (J wave, elevated ST segment) confined in right precordial leads. Brugada Pattern (BP) could be found in one or more right precordial leads, at conventional or higher intercostal spaces. A recent study, conducted by our group, reported that slightly less than one half of patients with type 1 BP show a definite ST segment depression (≥0.1 mV with duration ≥ 0.08 s) in the inferior leads. With these premises, 4 distinct ST abnormalities phenotypes can be recognizable in Type 1 BP. We speculated the key role of orientation of right ventricular outflow tract in the thorax, particularly the inclination of anterior wall compared to the sternum, contributing to the determination of these various ECG phenotypes. An interactive program, ECGsim, able to simulate ECG appearance in several anatomical and electrical models, confirmed this assumption. This computed model affirmed the strict relationship between ST segment depression in the inferior leads and the ST segment elevation in right precordial leads, typical of type 1 BP. A horizontal right ventricular outflow tract, in fact, gives raise to abnormal BP vector directed both superiorly and anteriorly, explaining, at the same time, typical BP appearance in right precordial leads and ST segment depression in the inferior leads.

The Significance of Crochetage on the R wave of an Electrocardiogram for the Early Diagnosis of Pediatric Secundum Atrial Septal Defect.

The purpose of this study was to test the hypothesis that the incidence of crochetage on the R wave in inferior limb leads can be used for the diagnosis of pediatric secundum atrial septal defect (ASD). Two hundred fifty-six children with secundum ASD (case cohort) and 256 age- and gender-matched children without heart disease (control cohort) were included in the study. Statistical analyses were performed to test the relationship between the ASD and the crochetage on the R wave with a single lead and three leads, respectively. The impact of incomplete right bundle branch block (IRBBB) and ASD diameter (≥ 5 and < 5 mm) on ASD diagnosis were also explored. Crochetage on the R wave was observed in all three inferior limb leads on 28.13% (72/256, 28 with IRBBB) of subjects with secundum ASD, while it was seen in only 2.73% (7/256, one with IRBBB) of control subjects (P < 0.001). Subgroup analysis showed that the incidence of R wave crochetage correlated with ASD size in both the single inferior limb lead (26.14%, 23/88 on ASD ≥ 5 mm vs. 10.71%, 18/168 on ASD < 5 mm; P = 0.001) and all three inferior limb leads (44.32%, 39/88 on ASD ≥ 5 mm vs. 19.64%, 33/168 on ASD < 5 mm; P < 0.001). Our findings suggest that crochetage on the R wave in inferior limb leads can serve as an independent marker for ASD diagnosis.

Evaluation of baseline ECG in patients undergoing Oral Flecainide Challenge test for suspected Brugada Syndrome: An analysis of lead II.

BACKGROUND AND OBJECTIVES: We analyzed Lead II in patients undergoing an Oral Flecainide Challenge test (FCT), to identify any pointers that could predict a positive FCT and thereby help in recognition of latent BS. METHODS: The following parameters in lead II were retrospectively analyzed from the pre-test ECG in 62 patients undergoing FCT for suspected BS: The presence or absence of S waves, S wave amplitude, duration and upslope duration; J point parameters- Early repolarization, QRS notch, and QRS Slur; ST segment parameters-lack of isoelectric ST segment, ST duration and QT interval. RESULTS: 48 had positive FCT (Group-1) while 14 were negative for FCT(Group-2). Lack of an isoelectric ST segment (50% vs 14.29%, p = 0.018) and slurring of QRS (33.33% vs 0%, p = 0.014) was more common in Group-1 than Group-2. Group-1 had shorter ST segment duration (median 81.5 (IQR 64-103.5) vs 110 (IQR 90-132), p = 0.002) and shorter ST: QT ratio (median 0.28 (IQR 0.22-0.35) vs 0.23 (0.18-0.27), p = 0.007). QRS notch/depressed J point (87.5%), QRS slur (100%), and lack of isoelectric ST segment (92.31%) had high sensitivity for predicting an inducible Type 1 Brugada pattern. Combining two parameters- ST: QT ratio<0.24 and lack of isoelectric ST segment-considerably improved the specificity (73.3%), and the positive predictive value of the test to 76%. The results remained accurate when validated in a small prospective cohort. CONCLUSION: Shortened ST segment in Lead II, lack of isoelectric ST segment, slurred QRS and ST/QT ratio <0.24 are predictive of underlying Brugada pattern in baseline ECG.

A Case of Brugada Pattern Migrant from Right Precordial Leads to Peripheral Leads.

Since the first report in 1992, Brugada pattern (BP) diagnosis is mainly based on analysis of the precordial leads. In cases with no clear BP evidence in the conventional right precordial leads (4th intercostal space), limb leads analysis resulted helpful in suspecting BP. Fluctuations within right precordial leads between the diagnostic ECG pattern and nondiagnostic ECGs are well known. For the first time, in the patient herewith reported, the transformation of BP phenotype involves both precordial and peripheral leads, confirming that the analysis of all the 12 leads has a key role in BP diagnosis.

Q Wave in the Inferior Leads: There Is More Than Scar.

Q waves can regularly be observed in the 12-lead electrocardiogram either due to heart axis underlying pathology such as subacute myocardial infarction, myocardial scar, or accessory pathways. Rarely, other entities such as circumscribed hypertrophy can induce significant Q wave and represent an important differential diagnosis especially in younger patients. In the setting of atypical chest pain determination of the correct diagnosis can be challenging. Therefore, circumscribed hypertrophy should be taken into account to avoid unnecessary invasive procedures.

Diagnostic values of inferior Q-waves for myocardial scar identification detected by 3.0 T cardiac MRI.

While Q-waves in inferior leads, particularly lead III, can be regarded as a minor abnormality, it can also indicate the presence of myocardial scar. This study assessed the diagnostic value of pathologic inferior Q-waves (lead II, III, aVF) for detecting ischemic scars using a high-resolution 3.0 T cardiac magnetic resonance (CMR). We retrospectively analyzed 1692 patients with suspected or known coronary artery disease who underwent stress CMR perfusion or viability assessment. Pathologic Q-waves were defined as duration of ≥ 30 ms and depth of ≥ 1 mm or QS-complex. Eleven models were created to evaluate the presence of Q-waves in different combinations of inferior leads. Of the 1692 patients, 436 (25.8%) had pathologic Q-waves. Models with Q-waves in leads II + aVF (model 7) and II + III + aVF (model 9) showed high specificity (100% and 99.6%), positive predictive value (PPV) (80.0% and 86.7%), and negative predictive value (NPV) (82.6% and 84.3%) but low sensitivity (1.3% and 13.1%). Other models also maintained high specificity and NPV but poor sensitivity and PPV. Notably, 21% of patients with an isolated pathologic Q-wave in lead III (model 4) exhibited scars. These findings highlight the need for careful clinical assessment when pathologic Q-waves are present.

Inferior ST-Segment Elevation Caused by Occlusion of Left Anterior Descending Artery.

Here we present a case of a 70-year-old man with acute myocardial infarction caused by left anterior descending artery occlusion presenting as ST elevation in the inferior leads that suggested an occlusion of the right coronary artery. In contrast, coronary angiography results indicated a complete occlusion of the proximal left anterior descending coronary artery. We reported our observation in electrocardiographic data and coronary angiography and its changes after a percutaneous coronary intervention, and then we discuss its pathophysiologic mechanism.

De Winter Sign in Inferior Leads: A Rare Presentation.

De Winter pattern in anterior leads has been extensively described. However, there is only one case report of this pattern in inferior leads in English literature. Here, we describe a case of acute inferior wall myocardial infarction with thrombotic right coronary artery occlusion who presented with the classical De Winter sign in inferior leads.

Clinical analysis of suspected acute aortic dissection with ST-segment elevation detected by inferior leads / 中华急诊医学杂志

Objective To analyze the clinical characteristics of suspected acute aortic dissection with ST-segment elevation detected by inferior leads in order to avoid the misdiagnosis of acute aortic dissection facilitating an appropriate treatment strategy carried out in time.Methods A total of 14 patients with suspected acute aortic dissection with ST-segment elevation detected by inferior leads were enrolled.Their clinical presentation,ECG features,imaging findings,laboratory testing,coronary angiography results, treatment and outcome were retrospectively analyzed.Results Clinical characteristics of suspected acute aortic dissection with ST-segment elevation detected by inferior leads suggested that hypertension as a single risk factor accounted for 79%.The patients with normal blood pressure or high blood pressure in emergency visits accounted for 86%.The amplitude of ST elevation in lead Ⅲ was greater than that in lead Ⅱ,and lead Ⅲ accompanied with ST elevation in lead V1 or V4R accounted for 86%.Significantly elevated D-dimer >2 000 ng/mL was found in those patients.Coronary angiography showed that the opening of coronary artery not seen,normal coronary arteries or a simple right coronary artery proximal lesion.Transesophageal echocardiography and computed tomography angiography were used to identify the diagnosis with 100%accuracy.The mortality rate of this group was 50%.Conclusions Patients with acute aortic dissection evidenced by ST-segment elevation detected by inferior leads are in critical setting of high mortality. Emergency surgical treatment can significantly improve the survival rate of patients.