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QRS interval [keywords]
- [Left atrial and ventricular epicardial dual chamber pacing through a left lateral thoracotomy to treat pediatric complete atrioventricular block]. [English Abstract, Journal Article]
- Zhonghua Er Ke Za Zhi 2013 Aug; 51(8):578-83.
To investigate the feasibility, advantages and efficacy of implantation of left atrial and ventricular epicardial dual chamber pacemaker to treat pediatric complete atrioventricular block.Eleven children with median age 4.0 years (0.5-7.6 years) diagnosed as complete atrioventricular block resisting to drug therapy received implantations of left atrial and ventricular epicardial dual chamber pacemakers. Six were male and five female. Temporal or permanent right ventricular pacing was used for all of them before implantation of left atrial and ventricular epicardial dual chamber pacemakers. Three cases showed cardiac dysfunction. Left lateral thoracotomy was performed at 4th intercoastal space along anterior axillary line under general anesthesia, the pericardium was incised vertically anterior to the phrenic nerve, two pacing leads were individually located at left atrial appendage and left ventricular lateral wall. After all the parameters were detected to be satisfactory, a pouch was made at left abdomen under coastal margin. Dual chamber pacemaker was connected with pacing leads through subcutaneous tunnels. The sizes of heart chambers, cardiac functions, parameters of pacemaker, sensitivity, pacing status, PR interval and QRS interval were closely followed up post-operatively.Implantations of pacemakers were successful for all of the patients with no complications associated with operations. Preoperative electrocardiograms showed QRS interval (180 ± 33)ms under right ventricular pacing, it decreased to (140 ± 24)ms after implantation of left atrial and ventricular epicardial dual chamber pacemaker, significantly lower than right ventricular pacing (t = 8.8, P < 0.05) . Atrioventricular (AV) interval was set at 90 ms, PR interval (124 ± 4)ms. Echocardiograms performed within 2-3 days after implantation of left atrial and ventricular epicardial dual chamber pacemakers showed that for the 3 cases who were previously under right atrial and right ventricular dual chamber pacing presenting cardiac dysfunction, their left ventricular diastolic diameter (LVDd) decreased from (46.3 ± 12.5) (32.0-55.0) ms to (44.7 ± 12.0) (31.0-53.0) mm and left ventricular ejection fraction (LVEF) increased from 30% ± 15% (18%-47%) to 44% ± 18% (33%-65%). During 2-14 months' follow up, LVEF increased progressively which became significantly higher than before (65% ± 8% vs. 30% ± 15%, t = 5.6, P < 0.05) . Cardiac chamber sizes and left ventricular systolic function for the other 8 patients maintain normal during follow up. Pacing status and sensitivity were satisfactory for all these patients during follow up.Implantation of left atrial and ventricular epicardial pacemaker might be considered for children diagnosed as complete atrioventricular block for whom endocardial pacemaker could not be implanted, due to its utmost protection for cardiac function with minimal injury and its ability to prevent or reverse pacemaker syndrome. Left atrial and left ventricular epicardium should be regarded as the first-choice and routine locations for epicardial pacing.
- Electrocardiogram voltage attenuation and shortening of the duration of P-waves, QRS complexes, and QT intervals. [Journal Article]
- Indian Heart J 2013 Sep-Oct; 65(5):614-7.
Multiple pathologies in concert may lead to attenuation of the electrocardiogram (ECG) voltage. A case of a patient illustrating the above is presented, who showed marked attenuation of the ECG voltage. Automated values of the amplitude of the ECG QRS complexes, P-waves, and T-waves (in mm), duration of the QRS complexes, P-waves, and QT intervals (in ms), in 2 ECGs were compared. The patient was a 64-year-old woman who developed in the setting of a fatal illness, pleural and pericardial effusions, pneumomediastinum, pneumoperitoneum, subcutaneous emphysema in the neck and chest, peripheral edema with weight gain of 43.4 lbs, marked hypoalbuminemia, abnormal liver tests, and renal failure. All the above pathologies led to a marked attenuation of the ECG voltage, and shortening of the mean P-wave, QRS complexes, and QTc interval durations. The postulated mechanism of the observed ECG phenomena is discussed.
- Sodium Channel Blockade With QRS Widening After an Escitalopram Overdose. [Journal Article]
- Pediatr Emerg Care 2013 Sep; 29(9):998-1001.
Escitalopram is rarely associated with prolongation of the QTc interval; however, there are no reported cases of QRS complex widening associated with escitalopram overdose. We report a case of a patient who presented with both QRS complex widening and QTc interval prolongation after an escitalopram overdose.A 16-year-old girl presented to the emergency department after ingestion of escitalopram, tramadol/acetaminophen, and hydrocodone/acetaminophen. Laboratory results were significant for 4-hour acetaminophen 21.1 μg/mL. Serum electrolytes including potassium, magnesium, and calcium were all normal. Initial electrocardiogram (ECG) revealed a widened QRS with an incomplete right bundle branch pattern. After administration of 100-mEq sodium bicarbonate, a repeat ECG revealed narrowing of the QRS complex and a prolonged QTc interval. Magnesium sulfate 2 g intravenous and sodium bicarbonate drip were initiated. A repeat ECG, 1 hour after the second, revealed normalization of the QRS complex and QTc interval.Prolongation of the QTc interval is an expected effect of escitalopram. Both escitalopram and citalopram are metabolized to the cardiotoxic metabolite S-didesmethylcitalopram and didesmethylcitalopram, respectively, which have been implicated in numerous cardiac abnormalities including widening of the QRS complex. Although never previously described with escitalopram, this mechanism provides a reasonable explanation for the QRS complex widening and incomplete right bundle branch block that occurred in our patient.Both QRS complex widening and QTc interval prolongation should be monitored in cases of escitalopram and citalopram overdoses.
- J Waves in Accidental Hypothermia. [JOURNAL ARTICLE]
- Circ J 2013 Nov 8.
Background: The J wave is an ECG marker of ventricular fibrillation. However, the prevalence and clinical implications of J waves in hypothermic patients remain unclear. Methods and Results: We evaluated the clinical characteristics and ECGs of patients who were admitted for accidental hypothermia (<35.0°C). J waves were defined as notches or slurs in the terminal part of the QRS complex with an amplitude ≥0.1mV. We analyzed the prevalence of J waves and the relationship between body temperature (BT) and J wave amplitude. We also examined the augmentation of J waves following variable R-R intervals in patients with atrial fibrillation. Furthermore, we assessed the incidence of ventricular arrhythmias. A total of 60 hypothermic patients were recruited (mean age, 64±9 years; 97% male). The mean BT was 31.3°C (range, 29.4-33.5°C). J waves, which disappeared after rewarming, were observed in 30 patients (50%), with a higher frequency in patients with lower BT. Higher amplitude of J waves was associated with lower BT (P<0.001). Of the 8 patients with J waves and atrial fibrillation, 4 exhibited an augmentation of J waves following a short R-R interval. Only 1 patient with J waves developed ventricular tachycardia during rewarming. Conclusions: The prevalence of J waves and their amplitude increased with the severity of hypothermia. The temporal development of J waves might not be associated with fatal arrhythmic events.
- Ginsenoside-Re ameliorates ischemia and reperfusion injury in the heart: a hemodynamics approach. [Journal Article]
- J Ginseng Res 2013 Jul; 37(3):283-92.
Ginsenosides are divided into two groups based on the types of the panaxadiol group (e.g., ginsenoside-Rb1 and -Rc) and the panaxatriol group (e.g., ginsenoside-Rg1 and -Re). Among them, ginsenoside-Re (G-Re) is one of the compounds with the highest content in Panax ginseng and is responsible for pharmacological effects. However, it is not yet well reported if G-Re increases the hemodynamics functions on ischemia (30 min)/reperfusion (120 min) (I/R) induction. Therefore, in the present study, we investigated whether treatment of G-Re facilitated the recovery of hemodynamic parameters (heart rate, perfusion pressure, aortic flow, coronary flow, and cardiac output) and left ventricular developed pressure (±dp/dtmax). This research is designed to study the effects of G-Re by studying electrocardiographic changes such as QRS interval, QT interval and R-R interval, and inflammatory marker such as tissue necrosis factor-α (TNF-α) in heart tissue in I/R-induced heart. From the results, I/R induction gave a significant increase in QRS interval, QT interval and R-R interval, but showed decrease in all hemodynamic parameters. I/R induction resulted in increased TNF-α level. Treatment of G-Re at 30 and 100 μM doses before I/R induction significantly prevented the decrease in hemodynamic parameters, ameliorated the electrocardiographic abnormality, and inhibited TNF-α level. In this study, G-Re at 100 μM dose exerted more beneficial effects on cardiac function and preservation of myocardium in I/R injury than 30 μM. Collectively, these results indicate that G-Re has distinct cardioprotectective effects in I/R induced rat heart.
- Electrocardiographic changes in patients responding to treatment with group I pulmonary arterial hypertension. [Journal Article]
- South Med J 2013 Nov; 106(11):618-23.
Various changes in conductivity as reflected in the electrocardiogram (ECG) have been associated with the onset and progression of pulmonary arterial hypertension (PAH). Little data exist as to whether the ECG can be used to identify patients responding to treatment.A retrospective chart review of patients diagnosed by right-sided cardiac catheterization as having group I PAH within the past 5 years was performed. A total of 121 patients were reviewed, of whom 36 were found to be responders to treatment and were included in our study. Patients were defined as responders by evidence of symptomatic improvement and decrease in right ventricular systolic pressure by at least 15%.Of 36 patients included, the majority were women (n = 26, 72%) with an average age of 59.6 years. Significant differences in right-sided heart pressures based on echocardiogram were noted between the pretreatment and posttreatment subsets, with a decrease in right atrial pressure from 12.7 to 7.6 mm Hg (P = 0.0035), right ventricular systolic pressure from 83.2 to 55.3 mm Hg (P < 0.0001), and estimated pulmonary arterial mean pressure from 53.8 to 38.9 mm Hg (P < 0.0001). Electrocardiographic parameters, including resting heart rate (80 vs 76 bpm; P = 0.3683), QRS duration (98 vs 99 msec; P = 0.8444), calculated QT interval (461 vs 454 msec; P = 0.4386), premature ventricular contractions (n = 0 vs 2; P = 0.1558), right axis deviation (n = 14 versus 14; P = 1.00), right bundle branch block (n = 13 vs 7; P = 0.1176), and various measurements of right ventricular hypertrophy showed no difference.Although the ECG may be useful in helping to evaluate the onset and progression of PAH, its utility is limited in assessing appropriate response to treatment in this patient population.
- Combination of veno-arterial extracorporeal membrane oxygenation and hypothermia for out-of-hospital cardiac arrest due to Taxus intoxication. [Journal Article]
- CJEM 2013; 15(0):1-4.
ABSTRACTA young woman presented with cardiac arrest following ingestion of yew tree leaves of the Taxus baccata species. The toxin in yew tree leaves has negative inotropic and dromotropic effects. The patient had a cardiac rhythm that alternated between pulseless electrical activity with a prolonged QRS interval and ventricular fibrillation. When standard resuscitation therapy including digoxin immune Fab was ineffective, a combination of extracorporeal membrane oxygenation (ECMO) and hypothermia was initiated. The total duration of low flow/no flow was 82 minutes prior to the initiation of ECMO. After 36 hours of ECMO (including 12 hours of electrical asystole), the patient's electrocardiogram had normalized and the left ventricular ejection fraction was 50%. At this time, dobutamine and the ECMO were stopped. The patient had a full neurologic recovery and was discharged from the intensive care unit after 5 days and from the hospital 1 week later.
- An Analysis of the U-Wave and Its Relation to the T-Wave in Body Surface Potential Maps for Healthy Subjects and MI Patients. [JOURNAL ARTICLE]
- Ann Noninvasive Electrocardiol 2013 Nov 5.
The aim of this study was to analyze the U-wave morphology and its relation to the T-wave in one group of healthy subjects and in two groups of myocardial infarction (MI) patients-with and without ventricular tachycardia (VT) episodes. The context of the U-wave origin was also discussed and the U-wave as a potential marker of VT was investigated.The study was carried out on three groups of subjects: 20 healthy subjects, 14 MI patients not at risk of VT, and 22 MI patients at risk of VT. The morphology of the repolarization phase was examined in the high-resolution body surface potential maps recorded from 64 surface ECG leads. The temporal and spatial distributions of several ECG parameters were studied.The U-wave was present in almost all the studied subjects. The spatial heterogeneity and smooth change in both the T- and U-wave shapes on the entire torso were observed in all the studied groups. The statistical significance of discrimination between the MI patients without VT and MI patients with VT was observed for QRS interval, QT interval, U-wave integral, and normalized U-wave integral.High-resolution measurement of body surface potentials and an advanced data analysis allow for a detailed description of U-wave morphology and its relation to the T-wave. This might be of value in discriminating intracardiac repolarization effects, mechano-electrical feedback, and arrhythmia risk stratification.
- 5-year serial follow-up of clinical condition and ventricular function in patients after repair of tetralogy of Fallot. [Journal Article]
- Int J Cardiol 2013 Nov 30; 169(6):439-44.
To study the changes over time in biventricular size and function, and clinical parameters in patients after repair of tetralogy of Fallot (TOF) without subsequent pulmonary valve replacement (PVR).We prospectively included 78 non-PVR patients (age 20(6-60)years at baseline), who were studied twice with a 5-year interval. Patients underwent magnetic resonance imaging for assessment of biventricular size and function. Exercise testing and electrocardiography were performed to determine peak oxygen uptake (peak VO2) and QRS duration. N-terminal prohormone brain natriuretic peptide (NT-proBNP) was assessed additionally.Pulmonary regurgitation (PR), right ventricular (RV) volumes and QRS duration increased during 5-year follow-up (RV end-diastolic volume (EDV) 130±30ml/m(2) to 138±34ml/m(2); QRS 132±27msec to 139±27msec); peak VO2 decreased (96±19% to 91±17%). RV ejection fraction, RV effective stroke volume (eff.SV), and NT-proBNP levels remained unchanged. The slope of RVEDV increase was 1.6±3.0ml/m(2)/year, and depended on RVeff.SV, not on RVEDV, at baseline. Increase in RVEDV correlated with increase in QRS duration over time (r=0.28, p=0.016), and with decrease in RV mass/EDV ratio over time (r=-0.42, p<0.001), not with decrease in peak VO2. In subgroup analysis, patients with larger RVs at baseline showed larger increase in PR during follow-up and larger decrease in NYHA class over time.In TOF patients with moderate RV dilatation, RVEDV increased by 1.6±3.0ml/m(2)/year, irrespective of RV size at baseline, but depended on RVeff.SV at baseline. Despite limited progression in RV size, unfavourable changes occurred during 5years follow-up, which suggests there is a need for close follow-up.
- Usefulness of Echocardiographically Guided Left Ventricular Lead Placement for Cardiac Resynchronization Therapy in Patients With Intermediate QRS Width and Non-Left Bundle Branch Block Morphology. [JOURNAL ARTICLE]
- Am J Cardiol 2013 Oct 3.
The current guidelines most strongly support cardiac resynchronization therapy (CRT) for patients with heart failure with a QRS width of ≥150 ms and left bundle branch block (LBBB). Our objective was to assess the potential benefit of echocardiographically guided left ventricular (LV) lead positioning for patients with a QRS width <150 ms or non-LBBB as a substudy of the Speckle Tracking Assisted Resynchronization Therapy for Electrode Region (STARTER) prospective, randomized controlled trial. The STARTER trial randomized 187 patients with heart failure, a QRS of ≥120 ms, and ejection fraction of ≤35% to LV lead guided to the site of latest mechanical activation by speckle tracking radial strain versus routine implantation. The predefined primary end point was heart failure hospitalization or death within 2 years. This substudy included 151 CRT patients with matching echocardiographic and LV lead position data and complete follow-up data. Patients with a QRS width of 120 to 149 ms or non-LBBB and LV lead concordant or adjacent to the site of latest mechanical activation had favorable outcomes after CRT similar to those with LBBB or a QRS width of ≥150 ms. In contrast, patients with a QRS of 120 to 149 ms or non-LBBB and remote LV leads had unfavorable outcomes (hazard ratio 5.45, 95% confidence interval 2.36 to 12.6, p <0.001, and hazard ratio 4.92, 95% confidence interval 2.12 to 11.39, p <0.001, respectively, with significant interaction after adjusting for baseline variables, p = 0.038 and p = 0.008). In conclusion, LV lead positioning with respect to the echocardiographic site of latest activation was significantly associated with more favorable clinical outcomes in patients with a QRS duration <150 ms and/or non-LBBB. Additional prospective study is warranted.