Rate-dependent right precordial Q waves: “Septal focal block”

Gambetta, Miguel; Childers, Rory

doi:10.1016/s0002-9149(73)80120-1

Cited by 46 publications

(17 citation statements)

References 7 publications

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“…However, the precise mechanism by which SFB may contribute to a false-positive diagnosis of Q wave MI, particularly in the presence of RBBB, has not been identified. Consensus on ECG criteria for the SFB is also lacking: some investigators have attributed SFB to the apparent loss of anterior forces resulting in development of transient Q waves in leads V 1 –V 2 [10, 28, 29, 32], while others have linked SFB with the apparent increase of anterior forces in the horizontal but not the frontal plane (a tall initial R wave in the right chest leads without a change in QRS axis) [31, 33]. Still others [34, 35, 36]believe that this conduction block, depending on the site of insertion of the septal, anterior, and posterior fascicles, could produce an apparent loss or gain of anterior forces.…”

Section: Impact Of the Level Of Rbbb On Transseptal Conduction And Itmentioning

confidence: 99%

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False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block

Gussak

Wright²,

Bjerregaard

et al. 2000

Cardiology

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Right bundle-branch block (RBBB) has not traditionally been seen as an obstacle to ECG diagnosis of Q wave myocardial infarction (MI) – in clinical electrocardiography and vectorcardiography – because this conduction disturbance is not believed to cause significant alterations in the spatial orientation of initial excitation wavefronts. In the era of large-scale clinical trials, however, where serial ECG analysis is among the major diagnostic tools in MI classification, both false-positive and false-negative diagnoses of MI in the presence of RBBB have become increasingly evident. Because of the limited detectability of Q wave MI by ECG in the presence of RBBB, the electrocardiographic finding of Q wave MI should not be regarded as an independent diagnostic tool. It is best to utilize independent corroboration to establish the diagnosis of transmural infarction when RBBB is present. Further investigations are warranted to better delineate sensitivity, specificity, and predictive value of Q wave MI in the presence of RBBB.

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Section: Impact Of the Level Of Rbbb On Transseptal Conduction And Itmentioning

confidence: 99%

“…1). False-positive ECG diagnoses of a Q wave MI, particularly in the anteroseptal leads, are also not uncommon in clinical cardiology [10, 11, 12, 13](fig. 2).…”

Section: Introductionmentioning

confidence: 99%

False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block

Gussak

Wright²,

Bjerregaard

et al. 2000

Cardiology

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“…[1][2][3][4][5][6][7] With the prevalence of interventional therapy, it is thought that this phenomenon is increasing, but little is known regarding the physiological mechanism involved.Patients with acute MI always undergo echocardiography in order to evaluate changes in wall motion, left ventricular (LV) cavity, and LV function over time. Myocardial scintigraphy provides important information about myocardial perfusion and/or metabolism.…”

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confidence: 99%

Increase in Electrocardiographic R-Waves After Revascularization in Patients With Acute Myocardial Infarction

Isobe

Takada

Ando

et al. 2006

Circ J

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spontaneous increase in the electrocardiographic (ECG) R-wave voltage after acute myocardial infarction (MI) is a unique phenomenon, and regeneration of R-waves or disappearance of Q-waves after acute ischemic events has been reported. [1][2][3][4][5][6][7] With the prevalence of interventional therapy, it is thought that this phenomenon is increasing, but little is known regarding the physiological mechanism involved.Patients with acute MI always undergo echocardiography in order to evaluate changes in wall motion, left ventricular (LV) cavity, and LV function over time. Myocardial scintigraphy provides important information about myocardial perfusion and/or metabolism. Specifically, a combined study of myocardial metabolic tracer with perfusion tracer provides clues about the myocardial status in the healing stage of MI. [8][9][10] Perfusion -metabolism mismatch of the Circulation Journal Vol. 70, November 2006 perfusion/metabolic dual-tracers represents impaired but viable myocardium in the risk area, which is involved in functional recovery after revascularization in patients with acute MI. 11-13 Therefore, both examinations are cardinal diagnostic modalities for patients after acute MI.In this study, we performed dual-isotope scintigraphy and echocardiography, and compared the findings with ECG results to determine the physiological mechanism of the increase in ECG R-wave voltage during the acute to the subacute phase after revascularization in patients with acute MI. Methods PopulationOne hundred and seventy-one consecutive patients with first onset of acute MI who underwent emergency coronary revascularization, dual-isotope scintigraphy, and echocardiography between January 1998 and March 2004 were retrospectively examined. Acute MI was diagnosed by typical chest pain for >30 min, ECG ST-elevation of ≥0.1 mV (1 mm) in at least 2 contiguous leads, and a characteristic rise in plasma creatine kinase-MB activity. All patients underwent emergency coronary angiography (CAG) immediately after the ECG diagnosis and subsequent coronary revascularization. In the emergency CAG, antegrade flow was characterized using the Thrombolysis In Myocardial Background The physiological mechanism of the increase in the electrocardiographic (ECG) R-wave voltage after revascularization in patients with acute myocardial infarction (MI) needs to be elucidated. Methods and ResultsOne hundred and thirty-eight MI patients (83: anterior MI, 45: inferior MI, 10: lateral MI) underwent ECG and echocardiography in both the acute and subacute phases after emergency revascularization, as well as a resting thallium-201/iodine-123 15-p-iodophenyl-3-(R,S)-methyl pentadecanoic acid myocardial scintigraphy in the acute phase. The total sum of the R-wave voltage (∑R) was calculated over multiple leads on ECG for each infarcted lesion. Scintigraphic defect on each tracer was expressed as the percentage (%) defect of the total left ventricular (LV) myocardium. The % defect-discordance on both images in the acute phase and the % increase in ∑R an...

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“…Current thinking on the pathogenesis of Q-wave inlcrmittency involves either vascular or tissue related fac tors such as ischemia, myocardial hemor rhage and edema, dynamic changes in coro nary vascular tone of the infarct related ar tery, local reversible loss of electrical activity in severly hypoperfused ischemic but still via ble myocardial tissue [23] and interference with impulse conduction through the left bun dle branch responsible for septal activation [24], However, in patients with hypertrophic cardiomyopathy Q-waves variation could not be related to any recognized form of special ized conduction block. Abnormal electrophysiologic properties of the hypertrophic myo pathic myocardium has been ascribed to this phenomenon [25],…”

Section: Discussionmentioning

confidence: 99%

Electrocardiographic Q-Waves Inconstancy during Thrombolysis in Acute Anterior Wall Myocardial Infarction

Rechavia¹,

Blum²,

Mager³

et al. 1992

Cardiology

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It is the purpose of this paper to describe the electrocardiographic inconstancy of Q-waves during administration of thrombolytic therapy. This was documented in four patients given streptokinase early in the course of anterior wall myocardial infarction. Understanding the pathogenesis of sequential dynamic variations of Q-waves in this setting may offer important insights into coronary physiology and management of acute coronary events. We discuss the possible explanations for such changes with respect to tissue viability, dynamic vascular changes and electrophysiological properties of the reper-fused infarcted myocardium.

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Rate-dependent right precordial Q waves: “Septal focal block”

Cited by 46 publications

References 7 publications

False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block

False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block

Increase in Electrocardiographic R-Waves After Revascularization in Patients With Acute Myocardial Infarction

Electrocardiographic Q-Waves Inconstancy during Thrombolysis in Acute Anterior Wall Myocardial Infarction

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