Simultaneous wide and narrow QRS complex tachycardias in a child: what is the mechanism?
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Biomedical subjects
Publications and source records attributed to Gabriele Bronzetti.
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We investigated the efficacy of transcatheter patent foramen ovale (PFO) closure to prevent recurrent cerebral ischemic events in patients who did and those who did not have thrombophilia. Patients who have a PFO and an associated thrombophilia may have an increased risk of cerebral ischemic events. Seventy-two consecutive patients (mean age 42 +/- 13 years) underwent percutaneous PFO closure because of a cerebral stroke (51%) or a transient ischemic attack (49%). A thrombophilia was found in 20 patients (28%). A large right-to-left shunt through the PFO was found in 44 patients (61%) and an atrial septal aneurysm was found in 39 (54%). After the first event, 18 of 20 patients (90%) with a thrombophilia received oral anticoagulation. Before closure, patients who had a thrombophilia also had a higher rate of recurrences than patients who did not (p <0.0001), despite a similar follow-up (p = 0.14) and regardless of shunt entity (p = 0.59), presence of an atrial septal aneurysm (p = 0.98), and a prevalence of cardiovascular risk factors (p = 0.44). PFO closure was successful in all patients. Five patients (8%) had a residual shunt at 6 months. At 20 +/- 11 months after PFO closure, 3 recurrent events occurred (4%), and the recurrence rate was similar in patients who did and those who did not have a thrombophilia (p = 0.25). Thus, in patients who have a cryptogenic stroke, the association of a PFO with a thrombophilia significantly increases the risk of recurrences. Thus, transcatheter PFO closure is effective for preventing recurrences in patients who have a thrombophilia.
OBJECTIVES: We sought to evaluate the course of cardiopulmonary function after transcatheter atrial septal defect (ASD) closure and to identify the physiopathologic mechanisms leading to this change. BACKGROUND: Conflicting reports exist on cardiopulmonary functional improvement in asymptomatic adults after transcatheter closure of a secundum ASD. METHODS: Thirty-two consecutive adults (13 males; age 42.6 +/- 16.7 years) underwent maximal cardiopulmonary exercise testing and transthoracic echocardiography both on the day before and six months after transcatheter ASD closure. Mean pulmonary artery pressure, pulmonary to systemic flow ratio (Qp/Qs), and ASD diameter were measured before closure. RESULTS: Peak oxygen uptake (Vo(2)) (p < 0.001), peak oxygen pulse (p = 0.0027), and vital capacity (p = 0.0086) improved after ASD closure, although peak heart rate did not. A significant correlation was found between peak Vo(2) improvements and Qp/Qs (p = 0.0013). Left ventricular ejection fraction (LVEF) (p < 0.0001) and left ventricular end-diastolic diameter (LVEDD) (p < 0.0001) significantly increased after six months, although left ventricular end-systolic diameter did not. Right ventricular long- and short-axis dimensions decreased (both p < 0.0001). Peak Vo(2) and of peak oxygen pulse improvements correlated to both LVEF (p = 0.0009 and 0.0019, respectively) and LVEDD (p < 0.0001 and 0.032, respectively) increments. The decrease of both long- and short-axis right ventricular dimensions positively correlated to both LVEF and LVEDD improvements. The improvement in LVEF correlated to Qp/Qs (p = 0.0026). CONCLUSIONS: Transcatheter ASD closure leads to a significant improvement in cardiopulmonary function within six months, via an increase in peak oxygen pulse. An increase in both left ventricular stroke volume and cardiac output due to a positive ventricular interaction is the mechanism leading to improved peak Vo(2).
A significant association has been suggested between a residual shunt and the risk of cerebral ischemic recurrences after transcatheter patent foramen ovale (PFO) closure. We report the use of a detachable coil to treat a residual shunt in a patient who had a recurrent cerebral ischemic event after transcatheter closure of a PFO.
BACKGROUND: In adults with an atrial septal defect (ASD) transcatheter closure leads to an improvement of peak oxygen uptake (VO2), but the kinetics of recovery of VO2 after maximal exercise in this patient population and the impact of transcatheter ASD closure have never been investigated. METHODS: Twenty consecutive patients underwent a maximal cardiopulmonary exercise test both the day before and 6 months after transcatheter ASD closure. For comparison, an age- and sex-matched group consisting of 53 healthy adults was built. The constant decay of VO2, CO2 production (VCO2), minute ventilation (VE), and heart rate (HR), expressed as the first-degree slope of a single linear relation, were calculated for the first minute of recovery. RESULTS: Patients with an ASD had a prolonged VO2 slope (P =.0012), VCO2 slope (P =.0003), and VE slope (0.013) when compared with control subjects. Six months after transcatheter ASD closure, significant improvements of VO2 slope (P =.0043) and of VCO2 slope (P =.0022) were recorded, so that no difference was found when compared with those of the control group (P =.1 and P =.06, respectively). The VE slope and HR slope did not change after closure. A significant association between VO2 slope and peak VO2 in the group of patients with ASD was shown by the Spearman correlation, both before (r = 0.67, P =.0012) and after ASD closure (r = 0.71, P =.0004). CONCLUSIONS: A limited cardiopulmonary reserve in adults with no symptom who have an ASD appears to affect not only maximal exercise responses but also the recovery phase. Transcatheter ASD closure induces a significant improvement of the ability of recovering from maximal exercise and eliminates the difference with a healthy population.
Posterior fossa malformations, hemangiomas, arterial anomalies, coarctation of the aorta, and cardiac defects and eye abnormalities (PHACE) is a rare congenital anomaly with a broad spectrum of clinical manifestations with a striking female predominance. We describe an infant with PHACE anomaly and aortic coarctation who underwent cardiac catheterization to clearly define the complex anatomy of the aortic lesion before surgical repair. Review of the literature documents a highly significant association between ipsilateral hemangiomas and cerebrovascular and aortic arch anomalies. We conclude that cardiac catheterization is required to define the complex anatomy of aortic lesions and should be performed in all patients with PHACE and evident aortic involvement to plan appropriate and safe surgical repair.
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The association between recurrent episodes of pulmonary embolism, stroke, and congenital anomalies of the clotting system features a condition of increased risk of recurrences despite anticoagulant therapy. We report the successful management of this association with percutaneous closure of the foramen ovale and placement of an inferior caval vein filter.
BACKGROUND: Junctional ectopic tachycardia (JET) is a life-threatening arrhythmia producing severe hemodynamic dysfunction, which may complicate the postoperative course of surgery for congenital heart disease. Strict care and a fast and effective antiarrhythmic strategy are essential, because mortality largely depends on the duration of the arrhythmia. METHODS: Seven consecutive neonates with postoperative JET without any evidence of myocardial ischemia received intravenous flecainide after conventional therapies proved ineffective. Atrial pacing at the minimal rate for atrioventricular synchrony was followed by a 10-min intravenous infusion of 1.6 mg/kg flecainide, then continuous infusion of 0.4 mg/kg flecainide per hour. Treatment was considered effective based on restoration of sinus rhythm or a JET rate no higher than 170 bpm within 4 hours of flecainide loading. Overall mean flecainide infusion lasted 31.2 hours (range 25 to 53 hours). Side effects were assessed by monitoring plasma flecainide levels, electrocardiogram, arterial pressure, and central venous pressure. RESULTS: Flecainide was effective in all 7 patients after an infusion duration of 3.6 +/- 1.5 hours. Sinus rhythm was restored after 7.2 +/- 9.7 hours. After 4 hours of loading, heart rate fell from 219 +/- 14 to 136 +/- 7 bpm (p < 0.0001), arterial pressure increased from 69 +/- 8 to 93 +/- 10 mm Hg (p < 0.0001), while central venous pressure decreased from 8.0 +/- 1.6 to 5.2 +/- 1.9 mm Hg (p = 0.0007). No side effect or recurrence was noted. CONCLUSIONS: Flecainide can exert a fast antiarrhythmic effect on postoperative JET, and its infusion can be modulated to maintain the concentration within the therapeutic range, thus avoiding toxicity. We propose further consideration of flecainide for treatment of JET in neonates without myocardial ischemia.
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The aim of the study was to evaluate the time course of atrial and ventricular function improvement following internal atrial cardioversion in patients with structural heart disease. Twenty-nine patients with chronic persistent atrial fibrillation (AF) and underlying structural heart disease were followed by serial echocardiograms performed at 1 and 6 hours, 1 day, 1, 2, and 3 weeks, and 1, 2, 3, and 6 months after successful cardioversion. Sinus rhythm was maintained at 6 months in 24 patients. Following cardioversion the time course of left atrial mechanical function (peak A wave, percent A wave filling) differed from that of left ventricular ejection fraction: peak A wave values (cm/s) increased significantly at 1 week (51 +/- 23 vs 35 +/- 15 at 1 hour, P < 0.05), percent A wave filling (%) increased significantly at 2 weeks (34 +/- 12 vs 22 +/- 9 at 1 hour, P < 0.05), whereas left ventricular ejection fraction (%) increased later (at 1 month 60 +/- 14 vs 55 +/- 14 at baseline, P < 0.05 and at 2 months 60 +/- 14 vs 56 +/- 14 at 1 hour, P < 0.05). In conclusion, restoration of sinus rhythm results in an improvement in left ventricular ejection fraction during follow-up, even in patients with structural heart disease without fast ventricular rates at baseline. The dissociation between the time course of atrial and ventricular function improvement suggests that the latter was partly due to regression of a concealed form of cardiomyopathy and/or of a ventricular dysfunction due to chronic AF.
BACKGROUND: In adults with heart failure, neurohormonal overstimulation is related to the progression of the disease, and influences prognosis. beta-blockers, which modulate neurohormonal activation, now play an essential role in the pharmacological management of heart failure in adults, but their use in children is very limited. PATIENTS AND METHODS: To investigate the effects of carvedilol administration on neurohormonal activation and left ventricular function, carvedilol was added to standard treatment for heart failure in 9 patients with dilated cardiomyopathy due to heart muscle disease. Standard treatment has been in place for at least 1 month. The protocol consisted in a baseline evaluation to assess neurohormonal activation, and echocardiographic evaluation of left ventricular function. This was followed by a final evaluation at 12 months from carvedilol loading. Carvedilol was started at 0.05 mg/kg/day, and increased every two weeks until the target dose of 0.8 mg/kg/day was reached. RESULTS: Carvedilol administration was associated with a significant reduction in plasma norepinephrine (p = 0.00001), dopamine (p = 0.0001), aldosterone (p = 0.00001) and activation of the renin-angiotensin system (p = 0.0006). Similar reductions in vanilmandelic and homovanillic acid were noted. After 12 months, a positive remodeling took place, with significant reductions in end-diastolic (p = 0.004) and end-systolic diameters (p = 0.009), and an increase in left ventricular ejection fraction (p = 0.001). No adverse effects needing reduction or interruption in the dosage were noted in the run-in phase, nor in the period of maintenance. CONCLUSION: Carvedilol is a safe complement to standard therapy for heart failure in children, allowing a significant reduction of neurohormonal activation with evident benefits on both ventricular function and the clinical condition.
BACKGROUND: Many devices currently used for the closure of the patent ductus arteriosus are claimed to be safe and cost-effective, but only few data exist with respect to the gold standard of the Rashkind occluder. The aim of this study was to assess the efficacy and safety of three new different devices and to compare the results to those of a control group of patients carrying a Rashkind occluder. This should provide the basis for further cost-analysis studies. METHODS: The records of all patients who underwent closure of the patent ductus at our Institution from April 1989 to May 2001 were reviewed. Eighty patients (median age 10.3 years, median weight 27.6 kg) were treated (25 with a Rashkind device, 11 with Duct-Occlud coils, 35 with Cook detachable coils, 9 with the Amplatzer system). RESULTS: Kaplan-Meyer estimates of long-term complete occlusion of the ductus showed, compared to the Rashkind device, a significant improvement for the Cook and Amplatzer (p = 0.025 and p = 0.003, respectively) devices but not for the Duct-Occlud coils (p = 0.165). One patient of the Duct-Occlud group (9%) and 3 with the Rashkind device (12%) featured a significant residual shunt and needed a second intervention. The complication rate was 4% for the Rashkind occluder, 5% for the Cook coils, 9% for the Duct-Occlud system, and 11% for the Amplatzer device (p > 0.05). CONCLUSIONS: The new devices are as safe as the Rashkind occluder and provide effective treatment. The Cook coils and the Amplatzer occluder offer better results compared to the Rashkind and Duct-Occlud devices.