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Biomedical subjects

Ariel Roguin

Publications and source records attributed to Ariel Roguin.

At least 37 records · Page 2Linked to original sources
PubMed2005

Regional differences in systolic and diastolic function in arrhythmogenic right ventricular dysplasia/cardiomyopathy using magnetic resonance imaging.

Global and regional biventricular functions were analyzed in 14 patients diagnosed with arrhythmogenic right ventricular dysplasia/cardiomyopathy using cine magnetic resonance imaging and compared with similar data from 18 age-matched controls. In this study, we report results of quantitative evaluation of biventricular global and regional function using peak ejection rate and peak filling rate as measures of systolic and diastolic function, respectively (volumetric method).

Adolescent↗
PubMed2005

Internal defibrillation with minimal skeletal muscle activation: a new paradigm toward painless defibrillation.

BACKGROUND: Shock-induced pain produces substantial morbidity in recipients of implantable cardioverter-defibrillators (ICDs). This pain likely derives from activation of skeletal muscle and associated nerves in the chest and abdomen. In an effort to develop a painless defibrillation system, we designed an electrode arrangement that incorporates a conductive sock placed around the heart to confine the electric shock field to cardiac tissue. OBJECTIVES: The purpose of this study was to test whether cardiac defibrillation could be achieved without skeletal muscle activation using a novel electrode system. METHODS: Eight adult mongrel dogs were studied. Force of skeletal muscle contraction was measured by strain gauges attached to the forelimbs during delivery of internal shocks ranging in energy from 0.1 to 31 J. Biphasic shocks were delivered (1) between a right ventricular coil and a subcutaneous dummy can (standard configuration), and (2) between a left ventricular coil and an epicardial electrode sock. Internal and external defibrillation thresholds (DFTs) were determined for each electrode configuration. RESULTS: Shock-induced muscle contraction force was significantly lower using the sock electrode than with standard ICD electrodes at every shock energy level tested (P < .0001). Internal DFT was similar between electrode configurations (sock electrode: 8.6 +/- 4.2 J; standard: 11.0 +/- 6.3 J, P = .4), but muscle contraction force at DFT was greatly reduced with the new electrode system (1.8 +/- 2.0 kg vs 10.6 +/- 2.1 kg, P < .0001). The sock electrode rendered external defibrillation impossible, however, even at 360 J. CONCLUSION: Skeletal muscle activation induced by ICD shocks can be greatly reduced using an electrode system that confines the electric shock field to the heart. Refinement of this strategy may allow for delivery of painless shocks by ICDs. Further development is needed to overcome implant complexity and the higher external DFT with this type of electrode system.

Animals↗
PubMed2005

Predictors of appropriate implantable defibrillator therapies in patients with arrhythmogenic right ventricular dysplasia.

BACKGROUND: Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by ventricular arrhythmias and sudden cardiac death. The risk factors for sudden death and indications for implantable cardioverter-defibrillator (ICD) placement in patients with ARVD are not well defined. OBJECTIVES: The purpose of this study was to determine which clinical and electrophysiologic variables best predict appropriate ICD therapies in patients with ARVD. Particular attention focused on whether the ICD was implanted for primary or second prevention. METHODS: We enrolled 67 patients (mean age 36 +/- 14 years) with definite or probable ARVD who had undergone ICD placement. Appropriate ICD therapies were recorded, and Kaplan-Meier analysis was used to compare the event-free survival time between patients based upon the indication for ICD placement (primary vs secondary prevention), results of electrophysiologic testing, and whether the patient had probable or definite ARVD. RESULTS: Over a mean follow-up of 4.4 +/- 2.9 years, 40 (73%) of 55 patients who met task force criteria for ARVD and 4 (33%) of 12 patients with probable ARVD had appropriate ICD therapies for ventricular tachycardia/ventricular fibrillation (VT/VF; P = .027). Mean time to ICD therapy was 1.1 +/- 1.4 years. Eleven of 28 patients who received an ICD for primary prevention (39%) and 33 of 35 patients who received an ICD for secondary prevention (85%) experienced appropriate ICD therapies (P = .001). Electrophysiologic testing did not predict appropriate ICD interventions in patients who received an ICD for primary prevention. Fourteen patients (21%) received ICD therapy for life-threatening (VT/VF >240 bpm) arrhythmias. There was no difference in the incidence of life-threatening arrhythmias in the primary and secondary prevention groups (P = .29). CONCLUSION: Patients who meet task force criteria for ARVD are at high risk for sudden cardiac death and should undergo ICD placement for primary and secondary prevention, regardless of electrophysiologic testing results. Further research is needed to confirm that a low-risk subset of patients who may not require ICD placement can be identified.

Adolescent↗
PubMed2005

CT angiography is here--are we expected to see a change of angiography referral pattern?

A 52-year-old asymptomatic man, with cardiac risk factors of hypertension, Type II diabetes, hypertriglyceridemia, low HDL, obesity, and positive family history for early coronary artery disease (CAD), was referred to nuclear stress test. He exercised for 14 minutes, achieved his target heart rate, without any symptoms or ECG changes. Nuclear images were entirely normal. However, the patient was still concerned and anxious so he underwent CT angiography that revealed coronary narrowings. Next, he underwent coronary angiography with similar findings. The lesions were treated with stents. We present a case report to illustrate how newer technology such as CT angiography alters the way in which we diagnose CAD and decide on whether to pursue further invasive therapy.

Angioplasty, Balloon, Coronary↗
PubMed2005

Safety of bivalirudin during percutaneous coronary interventions in patients with abnormal renal function.

BACKGROUND: Chronic kidney disease is associated with an increased risk of ischemic and bleeding complications after percutaneous coronary intervention (PCI). Bivalirudin, a direct thrombin inhibitor, has been shown to reduce adverse bleeding events compared to unfractionated heparin in patients undergoing PCI. However, the effect of diminished renal function on the safety and efficacy of bivalirudin for PCI is unknown. We aimed to test the safety of bivalirudin in routine practice and to assess whether this benefit was influenced by renal function. METHODS AND RESULTS: The interaction between renal impairment and benefit from bivalirudin was assessed in 115 consecutive patients (age 68.5+/-12.1, 45% female) undergoing PCI. Bivalirudin dosing was adjusted based on renal function. Creatinine clearance (CrCl) was calculated using the Cockroft-Gault formula. The composite endpoints of in-hospital death, myocardial infarction or revascularization and bleeding events were assessed. Overall, these events occurred in 10 (8.7%) patients. Patients with a CrCl<60 ml/min had a significantly increased risk for in-hospital complications (18.6 versus 2.78%, P = 0.011). Univariate analysis for MACE and bleeding were significant for CrCl<60 ml/min OR: 2.54 (95% CI: 1.61-39.7, P = 0.011), age OR: 3.29 (95% CI: 1.07-1.39, P<0.001) and female gender OR: 2.1 (95% CI: 0.036-0.89, P = 0.036). Risk of complications increased with decreasing renal function: 2.7, 14.2, and 37.5% for CrCl of >60, 30-60 or <30 ml/min, respectively, P = 0.002). CONCLUSION: Advanced age, renal dysfunction, and female gender remain important risk factors for ischemic and bleeding complications in patients undergoing PCI with bivalirudin.

Aged↗
PubMed2005

Multimodality imaging of borderline left main coronary disease using fluoroscopy, IVUS and CT coronary angiography.

A borderline left main narrowing was discovered during coronary angiography in a young asymptomatic man with positive stress test. IVUS demonstrated minimal diameter of 2.9 mm and the cross-sectional area was 11.5 mm(2). CTs were performed, and an eccentric calcific plaque was imaged at the ostium of the left main. Based on all three image modalities after discussing the different therapeutic options with the patient he was referred for bypass surgery.

Coronary Angiography↗
PubMed2005

The association of subclinical coronary atherosclerosis with abdominal and total obesity in asymptomatic men.

The present study assesses and compares the association of waist circumference and body mass index with presence and severity of coronary artery calcium in asymptomatic men. The study population consisted of 451 asymptomatic men free of known coronary heart disease. The subjects were broadly divided into tertiles by waist circumference (< or =92 cm; 92.5-100 cm; > or =101 cm) and body mass index (< or =25.5 kg/m2; 25.6-28.4 kg/m2; > or =28.5 kg/m2), respectively. The risk of coronary artery calcium was two-fold higher among those with a waist circumference in the highest tertile (> or =101 cm) compared with men with waist circumference < or =92 cm. The relationship was found to be independent of body mass index, age, and conventional coronary heart disease risk factors. No significant association of body mass index with coronary artery calcium was observed. Our results are consistent with evidence that measures of central obesity, compared with body mass index, are more strongly related to clinical as well as subclinical coronary heart disease end points.

Adult↗
PubMed2005

Magnetocardiogram recordings in a nonshielded environment--reproducibility and ischemia detection.

BACKGROUND: Magnetocardiography (MCG) is a noninvasive technology that measures the magnetic field of the heart by superconducting quantum interference devices (SQUID) sensors. The novelty of the present system is that the sensors can be operated without electromagnetic shielding of the examination room, thus allowing the system to be easily installed in the emergency department or chest pain unit. Studies in shielded rooms, found that this imaging modality may have better sensitivity as compared to ECG in detecting ischemia. We aimed (1) to assess the reproducibility, intra-observer, and interobserver interpretation variability and (2) to assess the MCG maps in the presence of coronary narrowings. METHODS AND RESULTS: All measurements were performed in a nonshielded room. For the first part of the study, two MCG maps were recorded in 24 otherwise healthy volunteers (age 20-44 years, median 24, 16 male) in an interval ranging from 2 to 48 hours. The maps were interpreted using the CardioMag software for contour maps, averaged MCG time traces, and waveform morphology of repolarization by two observers blinded to each other. The parameters tested had low disagreement between repeated measurements. The correlations of the intra-observer and interobserver interpretation were excellent. Secondly, MCG maps were obtained in 29 patients referred for angiography due to suspected coronary artery disease. Nineteen of them had coronary narrowings defined as more than 50%. In this group, 16 (84.2%) had abnormal MCG maps as compared to only 5 (26.3%) who had abnormal ECGs (P < 0.01). CONCLUSIONS: MCG maps can be successfully obtained in a nonshielded room and allow feasible, accurate, and reproducible measurements with little intra-observer and interobserver variability. Ischemic changes in the heart's magnetic field may occur before electrical changes. Our pilot data suggests that this imaging modality may potentially offer better sensitivity as compared to rest ECG in detecting ischemia in a cohort of patients who had coronary narrowings identified by angiography.

Algorithms↗
PubMed2005

Hypoxia-inducible factor 1alpha polymorphism and coronary collaterals in patients with ischemic heart disease.

STUDY OBJECTIVES: Marked variability exists in coronary artery collaterals in patients with ischemic heart disease. Although multiple factors are thought to play a role in collateral development, the contribution of genetic factors is largely unknown. Hypoxia inducible factor 1 (HIF-1), a transcriptional activator that functions as a master regulator of oxygen homeostasis, is one possible genetic factor that could play an important role in modulating collateral development. DESIGN, SETTING, AND PARTICIPANTS: Collateral vessels were determined in 100 patients with > or = 70% narrowing of at least one coronary artery without acute myocardial infarction or prior revascularization. DNA was genotyped for the presence of a single nucleotide (C to T) polymorphism that changes residue 582 of HIF-1alpha from proline to serine. MEASUREMENTS AND RESULTS: The frequency of the T allele was significantly higher among patients without collaterals compared to patients with collaterals (0.188 vs 0.037, p < 0.001). In multivariate analyses, two variables affecting collateral formation were detected: two- or three-vessel coronary artery disease was a significant positive predictor (odds ratio [OR], 4.17; 95% confidence interval [CI], 1.61 to 10.8; p = 0.001), whereas the presence of HIF-1alpha genotype CT or TT was a negative predictor (OR, 0.19; 95% CI, 0.04 to 0.84; p = 0.03). CONCLUSIONS: These data suggest that variations in HIF-1alpha genotype may influence development of coronary artery collaterals in patients with significant coronary artery disease.

Adult↗
PubMed2005

Haptoglobin polymorphism predicts 30-day mortality and heart failure in patients with diabetes and acute myocardial infarction.

Patients with diabetes presenting with acute myocardial infarction (AMI) have an increased rate of death and heart failure. Patients with diabetes homozygous for the haptoglobin (Hp) 1 allele (Hp 1-1) develop fewer vascular complications. We tested the hypothesis that Hp type is related to the outcome of patients with diabetes presenting with AMI. We prospectively assessed the relationship between Hp type and 30-day mortality and heart failure in 1,437 patients with AMI (506 with diabetes). Multivariate logistic regression identified a significant interaction between Hp type and diabetes status on these outcome measures. Hp type was not related to outcome among patients without diabetes. In contrast, Hp 1-1 was associated with a strong protective effect with regard to the primary end point of death (OR 0.14, P = 0.015) and for death and heart failure (OR 0.35; 95% CI 0.15-0.86, P = 0.018) among patients with diabetes. Finally, among patients with diabetes, Hp 1-1 was associated with smaller infarct size. This study demonstrates that in patients with diabetes and AMI, the Hp type is an important determinant of clinical outcome and infarct size.

Diabetes Mellitus↗
PubMed2005

Angiogenesis--an update.

Angiogenesis, the growth of new blood vessels, is an essential process occurring both in health and in disease. This process is regulated by a complex interaction of angiogenesis-stimulating growth factors and by angiogenesis inhibitors. This review describes the underlying mechanisms and principles of angiogenesis, and summarizes its role in several pediatric topics as the retinopathy of prematurity, aseptic osteonecrosis, hemangiomas and vascular malformations and its role in pediatric malignancies.

Angiogenesis Inducing Agents↗
PubMed2004

Electrocardiographic features of arrhythmogenic right ventricular dysplasia/cardiomyopathy according to disease severity: a need to broaden diagnostic criteria.

BACKGROUND: The purpose of this study was to systematically study diagnostic and prognostic electrocardiographic (ECG) characteristics of arrhythmogenic right ventricle dysplasia/cardiomyopathy (ARVD/C). METHODS AND RESULTS: The patient population included 50 patients with ARVD/C (27 males, 23 females; mean age 38+/-15 years). We also analyzed the ECG of 50 age- and gender-matched normal control subject and 28 consecutive patients who presented with right ventricular outflow tract (RVOT) tachycardia. Right bundle-branch block (RBBB) was present in 11 patients (22%). T-wave inversions in V1 through V3 were observed in 85% of ARVD/C patients in the absence of RBBB compared with none in RVOT and normal controls, respectively (P<0.0001); epsilon waves were seen in 33%, and a QRS duration > or =110 ms in V1 through V3 was present in 64% of patients. Among those without RBBB, our newly proposed criterion of "prolonged S-wave upstroke in V1 through V3" > or =55 ms was the most prevalent ECG feature (95%) and correlated with disease severity and induction of VT on electrophysiological study. This feature also best distinguished ARVD/C (diffuse and localized) from RVOT. CONCLUSIONS: A prolonged S-wave upstroke in V1 through V3 is the most frequent ECG finding in ARVD/C and should be considered as a diagnostic ECG marker.

Adult↗
PubMed2004

Modern pacemaker and implantable cardioverter/defibrillator systems can be magnetic resonance imaging safe: in vitro and in vivo assessment of safety and function at 1.5 T.

BACKGROUND: MRI has unparalleled soft-tissue imaging capabilities. The presence of devices such as pacemakers and implantable cardioverter/defibrillators (ICDs), however, is historically considered a contraindication to MRI. These devices are now smaller, with less magnetic material and improved electromagnetic interference protection. Our aim was to determine whether these modern systems can be used in an MR environment. METHODS AND RESULTS: We tested in vitro and in vivo lead heating, device function, force acting on the device, and image distortion at 1.5 T. Clinical MR protocols and in vivo measurements yielded temperature changes <0.5 degrees C. Older (manufactured before 2000) ICDs were damaged by the MR scans. Newer ICD systems and most pacemakers, however, were not. The maximal force acting on newer devices was <100 g. Modern (manufactured after 2000) ICD systems were implanted in dogs (n=18), and after 4 weeks, 3- to 4-hour MR scans were performed (n=15). No device dysfunction occurred. The images were of high quality with distortion dependent on the scan sequence and plane. Pacing threshold and intracardiac electrogram amplitude were unchanged over the 8 weeks, except in 1 animal that, after MRI, had a transient (<12 hours) capture failure. Pathological data of the scanned animals revealed very limited necrosis or fibrosis at the tip of the lead area, which was not different from controls (n=3) not subjected to MRI. CONCLUSIONS: These data suggest that certain modern pacemaker and ICD systems may indeed be MRI safe. This may have major clinical implications for current imaging practices.

Animals↗
PubMed2004

Implantable cardioverter-defibrillators in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy.

OBJECTIVES: The aim of this study was to assess the outcome of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) patients treated with an implantable cardioverter-defibrillator (ICD). BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy is associated with tachyarrhythmia and an increased risk of sudden death. METHODS: This study included 42 ARVD/C patients with ICDs (52% male, age 6 to 69 years, median 37 years) followed at our center. RESULTS: Mean follow-up was 42 +/- 26 months (range 4 to 135 months). Complications associated with ICD implantation included need for lead repositioning (n = 3) and system infection (n = 2). During follow-up, one patient died of a brain malignancy and one had heart transplantation. Lead replacement was required in six patients as a result of lead fracture and insulation damage (n = 4) or change in thresholds (n = 2). During this period, 33 of 42 (78%) patients received a median of 4 (range 1 to 75) appropriate ICD interventions. The median period between ICD implantation and the first firing was 9 months (range 0.1 to 66 months). The ICD firing storms were observed in five patients. Inappropriate interventions were seen in 10 patients. Predictors of appropriate firing were induction of ventricular tachycardia (VT) during electrophysiologic study (EPS) (84% vs. 44%, p = 0.024), detection of spontaneous VT (70% vs. 15%, p = 0.001), male versus female gender (91% vs. 65%, p = 0.04), and severe right ventricular dilation (39% vs. 0%, p = 0.013). Using multivariate analysis, VT induction during EPS was associated with increased risk for firing in ARVD/C patients; odds ratio 11.2 (95% confidence interval 1.23 to 101.24, p = 0.031). CONCLUSIONS: Patients with ARVD/C have a high arrhythmia rate requiring appropriate ICD interventions. The ICD therapy appears to be well tolerated and important in the management of patients with ARVD/C.

Adolescent↗
PubMed2004

Crush stenting of bifurcational left subclavian-vertebral artery stenosis.

Left internal mammary artery (LIMA) has the best long-term patency in patients undergoing coronary artery bypass surgery. Stenosis of the proximal left subclavian artery (SA) may reduce flow to the LIMA, causing myocardial ischemia. We report a novel technique (crush stenting) for the treatment of a complex bifurcational left SA-vertebral artery (VA) stenosis in the presence of a patent LIMA bypass conduit. This technique limited plaque shifting, restored normal flow to all vessels, including the LIMA, and avoided devastating consequences of VA occlusion.

Aged↗