Papers by Parvin Dorostkar
Developments in Cardiovascular Medicine
Persistent junctional reciprocating tachycardia is an arrhythmia that usually presents in infancy... more Persistent junctional reciprocating tachycardia is an arrhythmia that usually presents in infancy or childhood but may not be recognized until adulthood. In older patients, the heart rate may not be sufficiently fast to result in enough symptoms to provoke further examination or evaluation by a physician. Age-related changes in both the rate and the intermittent nature of the tachycardia may mask the diagnosis. Thus, the diagnosis may be delayed until tachycardia-related symptoms or palpitations become more apparent. Presentation with heart failure is more common in younger patients. Since the heart rates associated with PJRT will most likely slow with age, radiofrequency ablation may usually be deferred in small children with this tachycardia. Because the tachycardia has a possible spontaneous or intermittent resolution, as well as variable expression of impaired ventricular function, and since it may be effectively and safely treated with ablation, this definitive therapy, whether radiofrequency current or cryotherapy, should be considered only in patients of suitable size and when there are symptoms related to the tachycardia.
Pediatric Research, Apr 1, 1997
Pacing and Clinical Electrophysiology, Jun 1, 2002
Introduction Rate adaptive pacing is aimed at providing appropriate pacing support throughout a f... more Introduction Rate adaptive pacing is aimed at providing appropriate pacing support throughout a full range of patient activities, including activities of daily living (ADL) and exertional tasks. 1 The performance and benefits of rate adaptive pacing have been well described in adult patients. However, the unique physiology and and activity patterns of children create challenges when providing pacing therapy in pediatric patients, especially in those participating in demanding physical activities requiring a high cardiac output. 2 Given the limited potential for increases in stroke volume during exercise in the growing child, an appropriate heart rate (HR) response spanning from rest to peak exercise (91 6 8 to 192 6 10 beats/min) becomes even more relevant. 3-5 Thus, pediatric patients could benefit from rate responsive pacemakers that are programmed to reach high upper rates (180 beats/min) following patterns similar to those observed during exercise in healthy children. Recently, Medtronic (Minneapolis, MN, USA) developed the Kappa 400 pacemaker series that has the capability of controlling pacing rate by an activity-based or a ventilation-based sensor. Because minute ventilation (MV) increases linearly with increasing metabolic rate up to about 60-70% VO 2 max, the authors focused on the HR
Blood, 2011
1967 Introduction: The cardiac QT interval (QT) has gained deserved scrutiny among electrophysiol... more 1967 Introduction: The cardiac QT interval (QT) has gained deserved scrutiny among electrophysiologists. Reflecting the duration of the ventricular myocardial depolarization/repolarization cycle, the QT depends upon ion exchange across cardiomyocyte membranes. Ion flux perturbations (due to abnormalities of membrane-bound ion channel number, structure or function) can predispose to QT prolongation that, in turn, is associated with linearly increasing risks of ventricular tachy-arrhythmias and sudden death. As both polypharmacy and dys-electrolytemia have been reported to affect QT, we studied the…
Journal of Electrocardiology, 2013
Pediatric Anesthesia, 2005
Automatic atrial tachycardia (AAT) is a rare supraventricular tachyarrhythmia (&a... more Automatic atrial tachycardia (AAT) is a rare supraventricular tachyarrhythmia (<10% of all supraventricular tachycardias), which can present in infants or young children. There are no published reports of AAT occurring in an infant or child following noncardiac surgery and general anesthesia. This report describes the management of a previously healthy 5-month-old infant, who developed AAT in the postanesthesia care unit following an uneventful circumcision under general anesthesia.
Journal of the American College of Cardiology, 1998
(d) on me EGG ¢,~,t ~n~d v~mtn,.'u~ t~.hyca~r~ (VT) ~d s~de~ ck~h ($0) IM~ A~ mpgn (~) of t~ o! F... more (d) on me EGG ¢,~,t ~n~d v~mtn,.'u~ t~.hyca~r~ (VT) ~d s~de~ ck~h ($0) IM~ A~ mpgn (~) of t~ o! Fallof (TOF), In th~ ~dy. we oxar~ lhetm n~_ o! ~ ~ a~¢l SO in a ta~]ef COhOrt of
Proceedings of the 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (IEEE Cat. No.03CH37439)
In anisotropic tissue (e.g., right atrium), nonuniform conduction may cause conduction block/dela... more In anisotropic tissue (e.g., right atrium), nonuniform conduction may cause conduction block/delay, or form a functional line of block, thus, providing a substrate for the initiation/maintenance of atrial arrhythmias. We tested the hypothesis that the activation patterns generated by bipolar, linear, triple site stimulation create more uniform propagation compared to single site stimulation, thereby, minimizing or eliminating potential substrates for initiation/maintenance of reentrant atrial arrhythmias. The canine sterile pericarditis model and normal dogs were studied. A plunge wire electrode pair was placed at the superior aspect of the crista terminalis (CT) for single site pacing. For triple site pacing, three bipolar pairs were placed perpendicular and parallel to the superior aspect of the CT in a linear fashion. Rapid pacing using different electrode configurations was performed at 200 ms and 300 ms cycle lengths up to 6 sec. During pacing, 404 unipolar atrial electrograms were recorded simultaneously from electrode arrays placed on the atria. The data demonstrate that linear triple site pacing creates more uniform linear propagation with less or no conduction delay/block, in contrast to single site pacing which creates elliptical impulse propagation. These findings may help develop alternative pacing techniques for termination and/or prevention of atrial arrhythmias.
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society
ABSTRACT
Journal of the American College of Cardiology, 1998
1West Virginia University Department of Pediatrics 2Mayo Clinic Department Surgery 3Mayo Clinic D... more 1West Virginia University Department of Pediatrics 2Mayo Clinic Department Surgery 3Mayo Clinic Department of Emergency Medicine 4University of Minnesota School of Medicine Department of Pediatrics University of Minnesota Children’s Hospital 5University of Minnesota Children’s Hospital Emergency Department 6University of Minnesota School of Nursing 7ImageTrend, Inc., Lakeville, MN 8Pepperdine University School of Business 9University of Minnesota Department of Chemistry
Journal of Clinical Sleep Medicine, 2007
Disclosure Statement This is was not an industry supported study. Dr. Caples has received researc... more Disclosure Statement This is was not an industry supported study. Dr. Caples has received research support from ResMed Foundation. Dr. Rosen has received research support from Cephalon. Dr. Gami has participated in speaking engagements for Boston Scientific. Dr. Shivkumar has participated in speaking engagements for St. Jude Medical, Promedica, Boston Scientific, and Pfiedler Enterprises and has received travel compensation from St. Jude Medical, Pfiedler Enterprises, and Boston Scientific. Dr. Somers has received research support from ResMed Foundation. Dr. Stepanski has received research support from Takeda and meeting travel expenses from Sanofi-Aventis. Drs. Shen, Cotts, Adams, Dorostkar, Morgenthaler, and Iber have indicated no financial conflicts of interest.
The Journal of Thoracic and Cardiovascular Surgery, 1994
, 73 patients underwent first-stage reconstruction for hypoplastic left heart syndrome at the Uni... more , 73 patients underwent first-stage reconstruction for hypoplastic left heart syndrome at the University of Michigan Medical Center. During this period, surgical reconstruction remained essentiaUy constant and consisted of a pulmonary artery-to-aorta anastomosis with aUograft augmentation of the ascending, transverse, and proximal descending aorta, restriction of pulmonary blood flow with a polytetrafluoroethylene shunt from the innominate artery to the central pulmonary artery confluence, and atrial septectomy. Hospital survival was 62 of 73 patients, 85 % (70 % confidence limits: 80 % to 89 %). These results stand in marked contrast to those obtained during the earlier years of our experience from 1986 to 1989 when only 21 of 50 patients (42%,70% confidence limits: 35% to 49%) survived (p = 0.001). Among the most recent group of patients, only 2 of 7 patients older than 1 month of age at operation survived, whereas 60 of 66 (91 %, 70% confidence limits: 87% to 94%) patients younger than 1 month of age survived (p =0.0001). Anatomic subtype and ascending aortic diameter were not predictive of survival. Actuarial survivals for those patients younger than 1 month of age at the first-stage operation, including hospital deaths and subsequent operative procedures, were 81 %, 74%, and 74% at 6 months, 1 year, and 2 years, respectively. These results indicate that survival for patients after first-stage reconstruction for hypoplastic left heart syndrome has significantly improved in recent years. Older age was a strong risk factor, with a hospital survival of 91 % for those patients undergoing first-stage palliation within the first month of life. These data have important implications for the type of operative intervention and its timing.
Purpose: MyEIF.org (formerly MEMSCIS.org) is a tool to provide an emergency–focused clinical summ... more Purpose: MyEIF.org (formerly MEMSCIS.org) is a tool to provide an emergency–focused clinical summary for CSHCN in the format of the American College of Emergency Physicians/American Academy of Pediatrics Emergency Information Form (EIF). No description of a large experience in managing CSHCN in a disaster is available. We conducted a disaster drill for groups of CSHCN with cardiac and genetic diagnoses with or without an on-line EIF to measure increased disaster preparedness of parents and disaster care providers. Methods: The research has an overall goal to test training and performance of potential disaster health care providers and families of CSHCN in the disaster response for special needs children. Families enrolled in MyEIF.org participated along with volunteer parents and CSHCN plus disaster health care providers in a disaster simulation exercise designed to train providers to use the MyEIF.org system, to educate parents regarding possible disasters that could affect their s...
Catheterization and Cardiovascular Diagnosis, 1996
In a canine puppy model, pulmonary artery stenosis was created by banding the left pulmonary arte... more In a canine puppy model, pulmonary artery stenosis was created by banding the left pulmonary artery to 3040% of its original diameter. Animals underwent right heart catheterization and angiography 1-2 mo later, and Palmaz P308 stents were implanted. Stent redilation was performed 3-5 mo later. One mo postredilation, the animals were restudied and sacrificed. Coarctations of the aorta were created by transverse aortic incislon and longitudinal repair. P308 stent implantation was performed 2-3 mo later. Stent redilation was performed after &lo mo, and the animals were restudied and sacrificed 1-2 mo later. Stent implantation was performed in 6 puppies with pulmonary artery stenosis, as 2 animals developed postoperative pulmonary arterial hypoplasia, precluding stenting. The stenosis diameter increased from 4.8 2 0.5 mm to 7.4 4 0.6 mm (mean 2 SE) following stenting (P = 0.005), and increased further to 9.2 f 0.7 mm following redilation (P <: 0.001). There were no significant vessel tears or ruptures. Coarctation stenting was performed in 8 animals. The coarctation was dilated from 5.8 ? 0.9 mm to 9.8 ? 0.6 mm (P '. O.OOl), and to 13.5 f 0.5 mm at redilation (P = 0.002). Redilation could not be performed in 1 animal. Aortic rupture and death occurred in 2 of 7 animals at redilation. Stent implantation and redilation in experimental pulmonary artery stenosis appears safe and effective. Though stent implantation for coarctation of the aorta appears safe, there was a 28% aortic rupture rate at stent redilation in this model.
Pacing and Clinical Electrophysiology, 2005
The anatomic substrate for protected isthmus conduction in the right atrium has been well defined... more The anatomic substrate for protected isthmus conduction in the right atrium has been well defined. Little is known of similar substrates in the left atrium (LA). Patients (pts) with reentrant tachycardia (AVRT) supported by a single left-sided accessory pathway were studied retrospectively (n = 64) and prospectively (n = 31). Intracardiac electrograms were recorded from the His bundle position and coronary sinus (CS). The LA was mapped with a steerable catheter using the transseptal approach. LA anatomy was examined grossly and histologically in six cadaver hearts after removal of endocardium. A distal-to-proximal CS activation sequence during AVRT was seen in all patients with a left lateral accessory pathway before ablation. After one to three radiofrequency (RF) energy deliveries that did not interrupt accessory pathway conduction, the CS activation sequence was reversed in three patients in the retrospective group and bidirectional conduction block in the posterior atrioventricular vestibule of the LA (PAVV) was demonstrated in nine patients in the prospective group. Four of the six cadaver hearts showed a distinct circumferential inferoposterior myocardial bundle that coursed parallel to the CS in the PAVV. We described evidence of bidirectional intraatrial block in the PAVV after application of RF energy during accessory pathway ablation. Such conduction block may mimic the presence of a second accessory pathway. Our data suggest that circumferential conduction in the PAVV may be poorly coupled to the rest of the LA and may be involved in the macro-reentrant circuit around the mitral annulus. The circumferential inferoposterior myocardial bundle may serve as the underlying anatomic substrate.
Journal of the American College of Cardiology, 2002
Background: Several noninvasive tests are available to risk stratify pts for sudden cardiac death... more Background: Several noninvasive tests are available to risk stratify pts for sudden cardiac death but are limited by the need for a normal QRS duration for accurate interpretation. Twave alternans (TWA) has been proposed as a noninvasive test that can be used in pts with left bundle branch block (LBBB). The purpose of this study was to compare and contrast the sensitivity and specificity of TWA in pts with and without LBBB. Methods: We prospectively evaluated 154 pts (101 men, mean age 62 ± 23 yrs) referred for EPS. All pts underwent EPS using programmed stimulation at two ventricular sites with up to triple extrastimuli with and without isoproterenol or dobutamine. At the time of EPS, all pts underwent TWA testing during rapid atrial pacing with the Cambridge Heart CH2000 or HearTwave system. TWA was interpreted according to standard protocol. Indeterminate tests were excluded from further analysis (31 pts, 20%). Positive EPS was defined as the induction of sustained monomorphic ventricular tachycardia with up to triple ventricular extrastimuli or ventricular fibrillation with up to double ventdcular extrastimuli. Results: 16 pts (13%) had LBBB on ECG and 107 pts (87%) had a normal QRS duration. There was no difference between the two groups with regard to gender, age, indication for EPS, presence of CAD, or use of beta blockers, However, LBBB was associated with a lower LVEF (28% ±8 vs. 40% ±15, p<0.001). 6 pts (38%) with LBBB and 34 pts (32%) with a normal QRS had positive EPS (p=0.78). In comparison, the positivity rate of TWA was 81% in pts with LBBB vs. 43% in pts with a normal QRS (p=0.006). The sensitivity of TWA for predicting inducibility at EPS was 83% in pts with LBBB and 47% in pts without LBBB (p=0.19). However, the specificity was only 20% in the pts with LBBB compared with 59% in the pts with normal QRS (p=0.04).
Journal of the American College of Cardiology, 2004
Journal of Electrocardiology, 2003
Atriofascicular pathways supporting antidromic reentrant tachycardia are uncommon, and may be dif... more Atriofascicular pathways supporting antidromic reentrant tachycardia are uncommon, and may be difficult to ablate. Traditional mapping can be associated with traumatic loss of atriofascicular conduction. Atriofascicular fibers can insert into the right bundle and will, therefore, first activate the right ventricle. In contrast to initial activation of the ventricle near the tricuspid annulus that can be seen in patients with right-sided decremental atrioventricular pathways. We used electroanatomic mapping to map and ablate the ventricular insertion of atriofascicular pathways in two patients during sinus rhythm and during atrial pacing. In our 2 cases an atriofascicular potential was recorded from below the tricuspid valve annulus and tagged. At this site, each pathway was ablated with one radiofrequency lesion. We describe 2 cases where electroanatomic mapping of the right ventricle was used to map and ablate atriofascicular pathways.
Circulation, 2001
Background Atrial fibrillation (AF) may cause life-threatening ventricular arrhythmias in patient... more Background Atrial fibrillation (AF) may cause life-threatening ventricular arrhythmias in patients with Wolff-Parkinson-White syndrome. We prospectively evaluated the effects of ibutilide on the conduction system in patients with accessory pathways (AP). Methods and Results In part I, we gave ibutilide to 22 patients (18 men, 31±13 years of age) who had AF during electrophysiology study, including 6 pediatric patients ≤18 years of age. Ibutilide terminated AF in 21 of 22 patients (95%) during or 8±5 minutes after infusion and prolonged the shortest preexcited R-R interval during AF. Successful ablation was performed in all patients. In part II, ibutilide was given to 18 patients (14 men, 28±21 years) to assess its effects on the AP and conduction system. Ibutilide prolonged the antegrade atrioventricular node effective refractory period (ERP) (from 252±60 to 303±70 ms; P <0.02). Ibutilide caused transient loss of the delta wave in 1 patient and abolished inducible tachycardia in ...
Uploads
Papers by Parvin Dorostkar