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Q Wave (q + wave)

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Medical Sciences100%

Selected Abstracts

Diagnostic Significance of a Small Q Wave in Precordial Leads V2 or V3

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010
Tetsuya Katsuno M.D.
Background: An abnormal Q wave is usually defined as an initial depression of the QRS complex having a duration of ,40 ms and amplitude exceeding 25% of the following R wave in any contiguous leads on the 12-lead electrocardiogram (ECG). However, much smaller Q waves are sometimes recorded on the ECG. This study investigated the diagnostic value of the small Q wave recorded in precordial leads V2 or V3 on the ECG. Methods: We investigated 807 consecutive patients who underwent coronary angiography. A small Q wave was defined as any negative deflection preceding the R wave in V2 or V3 with <40-ms duration and <0.5-mV amplitude, with or without a small (<0.1-mV) slurred, spiky fragmented initial QRS deflection before the Q wave (early fragmentation). ECG and coronary angiographic findings were analyzed. Results: The small Q wave was present in 87 patients. Multiple logistic regression analysis revealed that presence of a small Q wave was a strong independent predictor of any coronary artery stenosis or left anterior descending artery (LAD) stenosis (odds ratio = 2.706, 2.902; P < 0.001, < 0.001, respectively). Conclusion: A small Q wave (<40-ms duration and <0.5-mV amplitude) in V2 or V3 with or without early fragmentation significantly predicted the presence of CAD and, especially, significant stenosis in the LAD. Ann Noninvasive Electrocardiol 2010;15(2):116,123 [source]

Significance of Abnormal Q Waves in the Electrocardiograms of Adults Less than 40 Years Old

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2006
Rex N. MacAlpin M.D.
Background: Abnormal Q waves (AQW) in the electrocardiogram are commonly ascribed to underlying myocardial infarction (MI). As an imperfectly specific sign of MI, the usefulness of AQW in identifying MI depends on its incidence in the population studied. Methods: Eighty-two subjects under 40 years of age with AQW were compared with 82 subjects from the same institution aged ,40 years with similar AQW to determine the presence or absence of cardiac disease or MI. Results: Cardiac disease was present in 90.2% and 92.7% of the younger and older subjects, respectively, whereas MI was present in only 15.9% of younger subjects and in 68.3% of older subjects. Etiologies of cardiac disease differed between younger and older subjects. Some types of AQW were more useful than others in ruling MI in or out. Conclusions: AQW were a strong indicator of organic heart disease in both adult age groups, but their utility to indicate MI was age-dependent. In the population studied, MI was present in only a small minority of subjects under 40 years of age with AQW, but was usually present in older subjects with similar AQW. [source]

The Morphology Changes in Limb Leads after Ablation of Verapamil-Sensitive Idiopathic Left Ventricular Tachycardia and Their Correlation with Recurrence

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2008
SHU-YUAN YAO Ph.D
Objectives: This study was designed to explore the morphology changes in limb leads of ECGs after successful ablation of verapamil sensitive idiopathic left ventricular tachycardia (ILVT) and their correlation with tachycardia recurrence. Methods: Between January 2001 and December 2006, 116 patients who underwent successful ablation of ILVT were included in the study. Twelve-lead surface ECG recordings during sinus rhythm were obtained in all patients before and after ablation to compare morphology changes in limb leads. Results: The ECG morphology changes after ablation were divided into two categories: one with new or deepening Q wave in inferior leads and/or disappearance of Q wave in leads I and aVL, and the other without change. The changes in any Lead II, III, or aVF after ablation occurred significantly more in patients without recurrence of ventricular tachycardia (VT) (P < 0.0001, 0.002, and 0.0001, respectively). The patients with recurrence of VT tended to have no ECG changes, compared with those without recurrence of VT (P = 0.009). The sensitivity of leads II, III, and aVF changes in predicting nonrecurrence VT were 66.7%, 78.7%, and 79.6%, specificity were 100%, 75%, and 87.5%, and nonrecurrence predictive value of 100%, 97.7%, and 98.9%, respectively. When inferior leads changes were combined, they could predict all nonrecurrence patients with 100% specificity. Conclusions: Successful radiofrequency ablation of ILVT could result in morphology changes in limb leads of ECG, especially in inferior leads. The combined changes in inferior leads can be used as an effective endpoint in ablation of this ILVT. [source]

Diagnostic Significance of a Small Q Wave in Precordial Leads V2 or V3

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010
Tetsuya Katsuno M.D.
Background: An abnormal Q wave is usually defined as an initial depression of the QRS complex having a duration of ,40 ms and amplitude exceeding 25% of the following R wave in any contiguous leads on the 12-lead electrocardiogram (ECG). However, much smaller Q waves are sometimes recorded on the ECG. This study investigated the diagnostic value of the small Q wave recorded in precordial leads V2 or V3 on the ECG. Methods: We investigated 807 consecutive patients who underwent coronary angiography. A small Q wave was defined as any negative deflection preceding the R wave in V2 or V3 with <40-ms duration and <0.5-mV amplitude, with or without a small (<0.1-mV) slurred, spiky fragmented initial QRS deflection before the Q wave (early fragmentation). ECG and coronary angiographic findings were analyzed. Results: The small Q wave was present in 87 patients. Multiple logistic regression analysis revealed that presence of a small Q wave was a strong independent predictor of any coronary artery stenosis or left anterior descending artery (LAD) stenosis (odds ratio = 2.706, 2.902; P < 0.001, < 0.001, respectively). Conclusion: A small Q wave (<40-ms duration and <0.5-mV amplitude) in V2 or V3 with or without early fragmentation significantly predicted the presence of CAD and, especially, significant stenosis in the LAD. Ann Noninvasive Electrocardiol 2010;15(2):116,123 [source]

Fragmented QRS Complexes on 12-Lead ECG: A Marker of Cardiac Sarcoidosis as Detected by Gadolinium Cardiac Magnetic Resonance Imaging

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2009
Mohamed Homsi M.D.
Background: Fragmented QRS complexes (fQRS) on a 12-lead ECG are a marker of myocardial scar in patients with coronary artery disease. Cardiac sarcoidosis is also associated with myocardial granuloma formation and scarring. We evaluated the significance of fQRS on a 12-lead ECG compared to Gadolinium-delayed enhancement images (GDE) in cardiac magnetic resonance imaging (CMR). Method and results: The ECGs of patients (n = 17, mean age: 52 ± 11 years, male: 53%) with established diagnosis of sarcoidosis who underwent a CMR for evaluation of cardiac involvement were studied. ECG abnormalities included bundle branch block, Q wave, and fQRS. fQRS, Q wave, and bundle branch block were present in 9 (53%), 1 (6%), and 4 (24%) patients, respectively. The sensitivity and specificity of fQRS for detecting abnormal GDE were 100% and 80%, respectively. Sensitivity and specificity of Q waves were 11% and 100%, respectively. Conclusions: fQRS on a 12-lead ECG in patients with suspected cardiac sarcoidosis are associated with cardiac involvement as detected by GDE on CMR. [source]

Diagnostic Significance of a Small Q Wave in Precordial Leads V2 or V3

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010
Tetsuya Katsuno M.D.
Background: An abnormal Q wave is usually defined as an initial depression of the QRS complex having a duration of ,40 ms and amplitude exceeding 25% of the following R wave in any contiguous leads on the 12-lead electrocardiogram (ECG). However, much smaller Q waves are sometimes recorded on the ECG. This study investigated the diagnostic value of the small Q wave recorded in precordial leads V2 or V3 on the ECG. Methods: We investigated 807 consecutive patients who underwent coronary angiography. A small Q wave was defined as any negative deflection preceding the R wave in V2 or V3 with <40-ms duration and <0.5-mV amplitude, with or without a small (<0.1-mV) slurred, spiky fragmented initial QRS deflection before the Q wave (early fragmentation). ECG and coronary angiographic findings were analyzed. Results: The small Q wave was present in 87 patients. Multiple logistic regression analysis revealed that presence of a small Q wave was a strong independent predictor of any coronary artery stenosis or left anterior descending artery (LAD) stenosis (odds ratio = 2.706, 2.902; P < 0.001, < 0.001, respectively). Conclusion: A small Q wave (<40-ms duration and <0.5-mV amplitude) in V2 or V3 with or without early fragmentation significantly predicted the presence of CAD and, especially, significant stenosis in the LAD. Ann Noninvasive Electrocardiol 2010;15(2):116,123 [source]

Fragmented QRS Complexes on 12-Lead ECG: A Marker of Cardiac Sarcoidosis as Detected by Gadolinium Cardiac Magnetic Resonance Imaging

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 4 2009
Mohamed Homsi M.D.
Background: Fragmented QRS complexes (fQRS) on a 12-lead ECG are a marker of myocardial scar in patients with coronary artery disease. Cardiac sarcoidosis is also associated with myocardial granuloma formation and scarring. We evaluated the significance of fQRS on a 12-lead ECG compared to Gadolinium-delayed enhancement images (GDE) in cardiac magnetic resonance imaging (CMR). Method and results: The ECGs of patients (n = 17, mean age: 52 ± 11 years, male: 53%) with established diagnosis of sarcoidosis who underwent a CMR for evaluation of cardiac involvement were studied. ECG abnormalities included bundle branch block, Q wave, and fQRS. fQRS, Q wave, and bundle branch block were present in 9 (53%), 1 (6%), and 4 (24%) patients, respectively. The sensitivity and specificity of fQRS for detecting abnormal GDE were 100% and 80%, respectively. Sensitivity and specificity of Q waves were 11% and 100%, respectively. Conclusions: fQRS on a 12-lead ECG in patients with suspected cardiac sarcoidosis are associated with cardiac involvement as detected by GDE on CMR. [source]

Significance of Abnormal Q Waves in the Electrocardiograms of Adults Less than 40 Years Old

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2006
Rex N. MacAlpin M.D.
Background: Abnormal Q waves (AQW) in the electrocardiogram are commonly ascribed to underlying myocardial infarction (MI). As an imperfectly specific sign of MI, the usefulness of AQW in identifying MI depends on its incidence in the population studied. Methods: Eighty-two subjects under 40 years of age with AQW were compared with 82 subjects from the same institution aged ,40 years with similar AQW to determine the presence or absence of cardiac disease or MI. Results: Cardiac disease was present in 90.2% and 92.7% of the younger and older subjects, respectively, whereas MI was present in only 15.9% of younger subjects and in 68.3% of older subjects. Etiologies of cardiac disease differed between younger and older subjects. Some types of AQW were more useful than others in ruling MI in or out. Conclusions: AQW were a strong indicator of organic heart disease in both adult age groups, but their utility to indicate MI was age-dependent. In the population studied, MI was present in only a small minority of subjects under 40 years of age with AQW, but was usually present in older subjects with similar AQW. [source]

Frequency of Acute Coronary Syndrome in Patients with Normal Electrocardiogram Performed during Presence or Absence of Chest Pain

ACADEMIC EMERGENCY MEDICINE, Issue 6 2009
Samuel D. Turnipseed MD
Abstract Objectives:, The authors hypothesized that patients with active chest pain at the time of a normal electrocardiogram (ECG) have a lower frequency of acute coronary syndrome (ACS) than patients being evaluated for chest pain but with no active chest pain at the time of a normal ECG. The study objective was to describe the association between chest pain in patients with a normal ECG and the diagnosis of ACS. Methods:, This was a prospective observational study of emergency department (ED) patients with a chief complaint of chest pain and an initial normal ECG admitted to the hospital for chest pain evaluation over a 1-year period. Two groups were identified: patients with chest pain during the ECG and patients without chest pain during the ECG. Normal ECG criteria were as follow: 1) normal sinus rhythm with heart rate of 55,105 beats/min, 2) normal QRS interval and ST segment, and 3) normal T-wave morphology or T-wave flattening. "Normal" excludes pathologic Q waves, left ventricular hypertrophy, nonspecific ST-T wave abnormalities, any ST depression, and discrepancies in the axis between the T wave and the QRS. Patients' initial ED ECGs were interpreted as normal or abnormal by two emergency physicians (EPs); differences in interpretation were resolved by a cardiologist. ACS was defined as follows: 1) elevation and characteristic evolution of troponin I level, 2) coronary angiography demonstrating >70% stenosis in a major coronary artery, or 3) positive noninvasive cardiac stress test. Chi-square analysis was performed and odds ratios (ORs) are presented. Results:, A total of 1,741 patients were admitted with cardiopulmonary symptoms; 387 met study criteria. The study group comprised 199 males (51%) and 188 females (49%), mean age was 56 years (range, 25,90 years), and 106 (27%) had known coronary artery disease (CAD). A total of 261 (67%) patients experienced chest pain during ECG; 126 (33%) patients experienced no chest pain during ECG. There was no difference between the two groups in age, sex, cardiac risk factors, or known CAD. The frequency of ACS for the total study group was 17% (67/387). There was no difference in prevalence of ACS based on the presence or absence of chest pain (16% or 42/261 vs. 20% or 25/126; OR = 0.77, 95% confidence interval = 0.45 to 1.33, p = 0.4). Conclusions:, Contrary to our hypothesis concerning patients who presented to the ED with a chief complaint of chest pain, our study demonstrated no difference in the frequency of acute coronary syndrome between patients with chest pain at the time of acquisition of a normal electrocardiogram and those without chest pain during acquisition of a normal electrocardiogram. [source]

The Surface Electrocardiogram Predicts Risk of Heart Block During Right Heart Catheterization in Patients With Preexisting Left Bundle Branch Block: Implications for the Definition of Complete Left Bundle Branch Block

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010
BENZY J. PADANILAM M.D.
LBBB and Heart Block.,Background: Patients with left bundle branch block (LBBB) undergoing right heart catheterization can develop complete heart block (CHB) or right bundle branch block (RBBB) in response to right bundle branch (RBB) trauma. We hypothesized that LBBB patients with an initial r wave (,1 mm) in lead V1 have intact left to right ventricular septal (VS) activation suggesting persistent conduction over the left bundle branch. Trauma to the RBB should result in RBBB pattern rather than CHB in such patients. Methods: Between January 2002 and February 2007, we prospectively evaluated 27 consecutive patients with LBBB developing either CHB or RBBB during right heart catheterization. The prevalence of an r wave ,1 mm in lead V1 was determined using 118 serial LBBB electrocardiographs (ECGs) from our hospital database. Results: Catheter trauma to the RBB resulted in CHB in 18 patients and RBBB in 9 patients. All 6 patients with ,1 mm r wave in V1 developed RBBB. Among these 6 patients q wave in lead I, V5, or V6 were present in 3. Four patients (3 in CHB group and 1 in RBBB group) developed spontaneous CHB during a median follow-up of 61 months. V1 q wave ,1 mm was present in 28% of hospitalized complete LBBB patients. Conclusions: An initial r wave of ,1 mm in lead V1 suggests intact left to right VS activation and identifies LBBB patients at low risk of CHB during right heart catheterization. These preliminary findings indicate that an initial r wave of ,1 mm in lead V1, present in approximately 28% of ECGs with classically defined LBBB, may constitute a new exclusion criterion when defining complete LBBB. (J Cardiovasc Electrophysiol, Vol. pp. 781-785, July 2010) [source]