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QRS interval [keywords]
- Quantitative electrocardiographic measures, neuromuscular disorders, and survival in left ventricular hypertrabeculation/noncompaction. [Journal Article]
- Ann Noninvasive Electrocardiol 2013 May; 18(3):251-5.
Left ventricular hypertrabeculation/noncompaction (LVHT) is frequently associated with neuromuscular disorders (NMDs) and electrocardiographic (ECG) abnormalities. Quantitative ECG-measures (QEMs) are risk markers for mortality in cardiomyopathies. We measured QEMs in the ECGs in LVHT patients with and without NMDs.Included were patients in whom (a) LVHT was diagnosed between 1995 and 2011 and (b) baseline ECG recordings were available. All underwent a clinical examination and were invited for a neurological investigation. QRS duration, QT, QTc and PR intervals were analyzed. Survival status was assessed in June 2011.In 141 patients (mean age 54 years, 49 females) QRS duration ranged from 40 to 200 ms, a QRS duration >120 ms was found in 19% and was associated with increased age, heart failure, left ventricular dilatation and systolic dysfunction (P < 0.001). QT intervals ranged from 240 to 600 ms. The QTc intervals ranged from 302 to 612 ms, a QTc interval >440 ms was found in 38% and was associated with left ventricular dilatation and systolic dysfunction (P < 0.001). PR intervals ranged from 90 to 360 ms, a PR interval >200 ms was found in 16% and associated with left ventricular dilatation (P < 0.01). No QEM differences were found in 86 patients with and 13 without NMD. During 59 months follow-up 45 patients died. QEMs were no mortality predictors, whereas multivariate analysis identified heart failure (P < 0.01), atrial fibrillation (P < 0.01) and diabetes mellitus (P < 0.05) as mortality predictors.Prolonged QRS complexes, PR and QTc intervals in LVHT are associated with heart failure and left ventricular dilatation, but not with NMD. The prognostic role of QEMs in LVHT needs further investigations in larger series.
- Electrocardiographic predictors of sudden cardiac death in patients with left ventricular hypertrophy. [Journal Article]
- Ann Noninvasive Electrocardiol 2013 May; 18(3):225-9.
Left ventricular hypertrophy (LVH) has been associated with increased risk of sudden cardiac death (SCD), and improvements in risk stratification methodology are warranted.We evaluated electrocardiographic intervals as potential markers of SCD risk in LVH. Corrected QT, QRS, and JT intervals were evaluated in consecutive cases with SCD and LVH from the ongoing Oregon Sudden Unexpected Death study who underwent a 12-lead electrocardiogram (EKG) and echocardiogram prior to and unrelated to the SCD event. Comparisons of age, gender, body mass index, LV ejection fraction, and EKG intervals together with clinical conditions (hypertension and diabetes) were conducted with geographically matched controls that had coronary artery disease but no history of ventricular arrhythmias or cardiac arrest. LVH was determined using the modified American Society of Echocardiography equation for LV mass. Independent samples t-test, Pearson's chi-square test, and multiple logistic regression were used for statistical comparisons.Of the 109 cases and 49 controls who met study criteria, age, gender, and comorbidities were similar among cases and controls. The mean LV mass index was not significantly different in cases compared to controls. However mean QTc (470.6 ± 53.6 ms vs 440.7 ± 38.7 ms; P < 0.0001) and QRS duration (113.6 ± 30.0 ms vs 104.9 ± 18.7 ms; P = 0.03) were significantly higher in cases than controls. In logistic regression analysis, prolonged QTc was the only EKG interval significantly associated with SCD (OR 1.72 [1.23-2.40]).Prolonged QTc was independently associated with SCD among subjects with LVH and merits further evaluation as a predictor of SCD in LVH.
- Pre-excitation syndrome with a change in terminal QRS vector. [Journal Article]
- Acta Cardiol 2013 Apr; 68(2):219-21.
Most accessory pathways in pre-excitation syndrome are capable of antegrade conduction from atrium to ventricle, and identified by characteristic ECG abnormalities such as a delta wave (ventricular pre-excitation) and a shortened PR interval.Therefore, the traditional diagnosis method is to detect the initial changes of the QRS complex. Here we report a patient initially mistaken as having atrioventricular re-entrant tachycardia (AVRT) and concealed pre-excitation syndrome. A diagnosis of incomplete latent pre-excitation syndrome was established on the basis of differences between the ECGs during sinus rhythm and AVRT in terminal QRS vectors, demonstrated by intracardiac electrophysiological radiofrequency catheter ablation.
- Prognostic Significance of Left Ventricular Dyssynchrony by Phase Analysis of Gated SPECT in Medically Treated Patients With Dilated Cardiomyopathy. [JOURNAL ARTICLE]
- Clin Nucl Med 2013 Jul; 38(7):510-515.
PURPOSE:The study aimed to investigate the value of clinical variables and rest gated single-photon emission computed tomography (SPECT) in predicting cardiac deaths in medically treated dilated cardiomyopathy (DCM) patients.
METHODS:This is a retrospective study. Fifty-six consecutive hospitalized DCM patients who underwent rest gated SPECT myocardial perfusion imaging were initially recruited. Patients were further excluded for receiving heart transplantation, cardiac resynchronization treatment, and noncardiac death during follow-up. The remaining 48 medically treated DCM patients were selected into the final analysis. Phase analysis of gated SPECT was conducted to identify left ventricular (LV) dyssynchrony. Cardiac death during follow-up was considered as the only endpoint. Univariate and multivariate Cox proportional hazards regression analysis were performed to identify the independent predictors of cardiac death. Kaplan-Meier cumulative survival analysis with stratification was performed, and survival curves were compared by log-rank test.
RESULTS:The mean age was 47.5 ± 15.8 years (range, 15-76 yrs) and 85.4% were men. The mean LV ejection fraction was 22.2 ± 7.7%. During the follow-up period (22.7 ± 5.1 mos), 12 (25.0%) cardiac deaths occurred. Compared to survivors, patients with cardiac death had lower body mass index (BMI, P = 0.010), higher percent of prolonged QRS duration (QRSD, P = 0.043), and severe LV dyssynchrony (P = 0.002). Multivariate Cox analysis demonstrated that severe LV dyssynchrony [hazard ratio = 9.607, 95% confidential interval (95% CI) 2.064-44.713, P = 0.004] and BMI (hazard ratio = 0.851, 95% CI 0.732-0.989, P = 0.036) were predictive of cardiac death.
CONCLUSION:Left ventricular dyssynchrony assessed by phase analysis of gated SPECT and BMI are predictive of cardiac death in medically treated DCM patients.
- Antiarrhythmic effect of cardiac resynchronization therapy with triple-site biventricular stimulation. [JOURNAL ARTICLE]
- Europace 2013 May 21.
AIMS:The antiarrhythmic effect of triple-site biventricular stimulation (Tri-V) is poorly understood. This study aims to evaluate the effect of cardiac resynchronization therapy (CRT) on ventricular arrhythmia (VA) with Tri-V using a single right ventricular (RV) and double left ventricular (LV) lead.
METHODS AND RESULTS:Over a period of 3.5 years, 58 consecutive patients with New York Heart Association class II-IV heart failure, an LV ejection fraction of ≤0.35, and a QRS interval of ≥120 ms were enrolled. Acute haemodynamic responses to dual-site biventricular stimulation (Bi-V) and Tri-V were evaluated by assigning patients to a Bi-V or Tri-V group. Electrocardiogram parameters [QT interval, JT interval, and transmural dispersion of repolarization (TDR)] were measured over time after CRT. Spontaneous VA detected by telemetry was reviewed and confirmed. During a mean follow-up of 481 days after implantation, VA occurred in 2 of 22 patients in the Tri-V group and 14 of 36 patients in Bi-V group. Triple-site biventricular stimulation was thus associated with a decreased VA risk (P = 0.044). Multivariate Cox analysis showed that Tri-V pacing prevented arrhythmic events as compared with Bi-V pacing (hazard ratio, 0.13; 95% confidence interval, 0.029-0.610; P = 0.009). Ventricular repolarization indices at 6 months were significantly shortened in Tri-V compared with Bi-V (QTc, -23.6 vs. -14.1%, P = 0.008; JTc, -21.4 vs. -7.7%, P = 0.005; TDRc, -39.9 vs. -17.0%, P < 0.001).
CONCLUSION:Compared with Bi-V, Tri-V reduced VA during long-term follow-up. Improvements in repolarization parameters may result in antiarrhythmic effects.
- Cardiologic predictors of sudden death in patients with myotonic dystrophy type 1. [Journal Article]
- J Clin Neurosci 2013 Jul; 20(7):1002-6.
The aim of this study was to analyze survival, causes of death and cardiologic predictors of sudden death in a large cohort of patients with myotonic dystrophy type 1 (DM1). The study was comprised of 171 adult DM1 patients hospitalized at the Neurology Clinic in a 20-year period. Severe electrocardiographic (ECG) abnormality included at least one of the following: rhythm other than sinus, PR interval of ⩾240ms, QRS complex duration of 120ms or more, and second-degree or third-degree atrioventricular (AV) block. Survival data were analyzed by the Kaplan-Meier test, log-rank test and Cox regression analysis. During the mean follow-up period of 9.4±5.4years, a pacemaker was implanted in 5.8% of DM1 patients and 14% of patients died. The mean age at death was 55.6±12.5years. The most common causes of death in our cohort were sudden death (41.7%) and respiratory failure (29.2%). The presence of palpitations (hazard ratio [HR]=4.7, p<0.05) and increased systolic blood pressure (HR=9.8, p<0.05) were significant predictors of sudden death. Among ECG parameters, severe ECG abnormality (HR=4.7, p<0.05), right bundle branch block (RBBB; HR=3.9, p<0.05) and bifascicular block (HR=5.8, p<0.05) were significant predictors of sudden death.
- Application of the Multicenter Automatic Defibrillator Implantation Trial II Risk Score in a Nontrial Setting. [JOURNAL ARTICLE]
- Am J Cardiol 2013 May 11.
A post hoc analysis of the Multicenter Automatic Defibrillator Implantation Trial (MADIT) II showed that patients with high mortality risk score did not benefit from implantable cardioverter-defibrillator (ICD) therapy. We sought to determine whether MADIT II risk score can identify patients with greater mortality in a nontrial "real-world" setting. We included 382 consecutive patients who received ICD for primary prevention of sudden cardiac death at the Minneapolis Veterans Affairs Medical Center from 2006 to 2010. MADIT II score was calculated by assigning 1 point each for age >70 years, New York Heart Association class >II, atrial fibrillation, QRS >0.12 seconds, and blood urea nitrogen level >26 mg/dl. Scores 0, 1 to 2, and ≥3 were classified as low, intermediate, and high risk, respectively. Of the 382 patients, 14% were low risk, 54% intermediate risk, and 32% high risk. After 3.0 ± 1.6 years of follow-up, incidence of appropriate ICD shocks was similar (p = 0.21) across MADIT II risk score categories. However, mortality rate was 21, 54, and 134 per 1,000 patient-year follow-up in low, intermediate, and high-risk patients, respectively, p <0.0001. Compared with low-risk patients, mortality was 6.4× greater in high-risk patients (hazard ratio 6.36, 95% confidence interval 1.9 to 20.5; p = 0.002). The c-index for the MADIT II score for predicting death was 0.69 (95% confidence interval 0.63 to 0.75). In conclusion, MADIT II risk score successfully identified patients with greater mortality in a nontrial-based, primary-prevention ICD cohort.
- ECG Phenomena: Pseudopreexcitation and Repolarization Disturbances Resembling ST-Elevation Myocardial Infarction Caused by an Intraatrial Rhabdomyoma in a Newborn. [JOURNAL ARTICLE]
- Congenit Heart Dis 2013 May 13.
As is known from other reports, a rhabdomyoma or tumor metastasis may alter intracardiac electrical conduction, producing electrical phenomena like pseudopreexcitation or repolarization disturbances resembling ST-elevation myocardial infarction or Brugada's syndrome. We present a newborn with a giant atrial rhabdomyoma and additionally multiple ventricular rhabdomyomas. He presented with several electrocardiogram (ECG) phenomena due to tumor-caused atrial depolarization and repolarization disturbances. Except from the cardiac tumors, the physical status was within normal range. Initial ECG showed a rapid atrial tachycardia with a ventricular rate of 230 bpm, which was terminated by electrical cardioversion. Afterwards, the ECG showed atrial rhythm with frequent atrial premature contractions and deformation of the PR interval with large, broad P waves and loss of discret PR segment, imposing as pseudopreexcitation. The following QRS complex was normal, with seemingly abnormal ventricular repolarization resembeling ST-elevation myocardial infarction. The atrial tumor was resected with consequent vast atrial reconstruction using patch plastic. The ventricular tumors were left without manipulation. After surgery, pseudopreexcitation and repolarization abnormalities vanished entirely and an alternans between sinus rhythm and ectopic atrial rhythm was present. These phenomena were supposably caused by isolated atrial depolarization disturbances due to tumor-caused heterogenous endocardial activation. The seemingly abnormal ventricular repolarization is probably due to repolarization of the atrial mass, superimposed on the ventricular repolarization. Recognizably, the QRS complex before and after surgical resection of the rhabdomyoma is identical, underlining the atrial origin of the repolarization abnormalities before surgery.
- Analysis of electrocardiogram in chronic obstructive pulmonary disease patients. [Journal Article]
- Med Pregl 2013 Mar-Apr; 66(3-4):126-9.
Chronic obstructive pulmonary disease is the fourth leading cause of mortality worldwide. It is defined as a persistent airflow limitation usually progressive and not fully reversible to treatment. The diagnosis of chronic obstructive pulmonary disease and severity of disease is confirmed by spirometry. Chronic obstructive pulmonary disease produces electrical changes in the heart which shows characteristic electrocardiogram pattern. The aim of this study was to observe and evaluate diagnostic values of electrocardiogram changes in chronic obstructive pulmonary disease patients with no other comorbidity.We analyzed 110 electrocardiogram findings in clinically stable chronic obstructive pulmonary disease patients and evaluated the forced expiratory volume in the first second, ratio of forces expiratory volume in the first second to the fixed vital capacity, chest radiographs and electrocardiogram changes such as p wave height, QRS axis and voltage, right bundle branch block, left bundle branch block, right ventricular hypertrophy, T wave inversion in leads V1-V3, S1S2S3 syndrome, transition zone in praecordial lead and QT interval.We found electrocardiogram changes in 64% patients, while 36% had normal electrocardiogram. The most frequent electrocardiogram changes observed were transition zone (76.36%) low QRS (50%) and p pulmonale (14.54%). Left axis deviation was observed in 27.27% patients.Diagnostic values of electrocardiogram in patients with chronic obstructive pulmonary disease suggest that chronic obstructive pulmonary disease patients should be screened electrocardiographically in addition to other clinical investigations.
- The anesthetized guinea pig: An effective early cardiovascular derisking and lead optimization model. [JOURNAL ARTICLE]
- J Pharmacol Toxicol Methods 2013 May 4.