27 results on '"Razavi, Mehdi"'
Search Results
2. Orthostatic Hypotension as a Manifestation of Vitamin B12 Deficiency
- Author
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Ganjehei, Leila, Massumi, Ali, Razavi, Mehdi, and Wilson, James M.
- Subjects
Aged, 80 and over ,Hypotension, Orthostatic ,Vitamin B 12 ,Treatment Outcome ,polycyclic compounds ,nutritional and metabolic diseases ,Humans ,Female ,Vitamin B 12 Deficiency ,Case Reports ,Vitamins ,Biomarkers ,Syncope - Abstract
A 90-year-old woman with orthostatic hypotension and near-syncope was found to have a low-normal level of vitamin B(12) and no other medical findings that could explain her orthostasis. Her symptoms responded to vitamin B(12) replacement therapy. This case shows that vitamin B(12) deficiency can induce orthostatic hypotension and syncope that are correctable by vitamin B(12) replacement.
- Published
- 2012
3. Biventricular Intracardiac Device Implanted in a Patient with Persistent Left Superior Vena Cava
- Author
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Ganjehei, Leila, Barekatain, Armin, Razavi, Mehdi, Massumi, Ali, and Rasekh, Abdi
- Subjects
Cardiac Resynchronization Therapy ,Male ,Treatment Outcome ,Vena Cava, Superior ,Vascular Malformations ,Bundle-Branch Block ,Humans ,Cardiac Resynchronization Therapy Devices ,Equipment Design ,Phlebography ,Images in Cardiovascular Medicine ,Aged - Published
- 2012
4. Heterogeneity of Left Ventricular Signal Characteristics in Response to Acute Vagal Stimulation during Ventricular Fibrillation in Dogs
- Author
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Nazeri, Alireza, Elayda, MacArthur A., Dragnev, Lubomir, Frank, Christopher M., Qu, Jihong, Afonso, Valtino X., Rasekh, Abdi, Saeed, Mohammad, Cheng, Jie, Shuraih, Mossaab, Massumi, Ali, and Razavi, Mehdi
- Subjects
Time Factors ,Fourier Analysis ,Vagus Nerve Stimulation ,Cardiac Pacing, Artificial ,macromolecular substances ,Ventricular Function, Left ,Disease Models, Animal ,Dogs ,Heart Conduction System ,Ventricular Fibrillation ,cardiovascular system ,Laboratory Investigation ,Animals ,cardiovascular diseases ,Electrophysiologic Techniques, Cardiac - Abstract
Studies have shown that long-term vagal stimulation is protective against ventricular fibrillation; however, the effects of acute vagal stimulation during ventricular fibrillation in the normal heart have not been investigated. We examined the effects of acute vagal stimulation on ventricular fibrillation in a canine model. In 4 dogs, we induced 30-second periods of ventricular fibrillation by means of intraventricular pacing. During 2 of the 4 periods of fibrillation that we analyzed, vagal stimulation was delivered through electrodes in the caudal ends of the vagus nerves. Noncontact unipolar electrograms were recorded from 3 ventricular regions: the basal septum, apical septum, and lateral free wall. We then computed the most frequent cycle length, mean organization index, and mean electrogram amplitude for each region. During fibrillation, vagal stimulation shortened the most frequent cycle lengths in the basal septum (P=0.02) and apical septum (P=0.0001), but not in the lateral wall (P=0.46). In addition, vagal stimulation significantly reduced the mean organization indices in the apical septum (P0.001) and lateral wall (P0.001), but not in the basal septum (P=0.19). Furthermore, vagal stimulation raised the mean electrogram amplitude in the basal septum (P0.01) but lowered it substantially in the apical septum (P=0.00005) and lateral wall (P=0.00003). We conclude that vagal stimulation acutely affects the characteristics of ventricular fibrillation in canine myocardium in a spatially heterogeneous manner. This nonuniformity of response may have implications with regard to manipulating the autonomic system as a means of modifying the substrate for ventricular dysrhythmias.
- Published
- 2011
5. Stroke Prevention in Nonvalvular Atrial Fibrillation
- Author
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Ganjehei, Leila, Massumi, Ali, Razavi, Mehdi, and Rasekh, Abdi
- Subjects
Cardiac Catheterization ,Twelfth Symposium on Cardiac Arrhythmias ,Anticoagulants ,Dabigatran ,Stroke ,Treatment Outcome ,Atrial Fibrillation ,Preventive Health Services ,beta-Alanine ,Humans ,Atrial Appendage ,Benzimidazoles ,Warfarin ,Cardiac Surgical Procedures - Published
- 2011
6. The Evaluation and Management of Electrical Storm
- Author
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Eifling, Michael, Razavi, Mehdi, and Massumi, Ali
- Subjects
animal diseases ,Electric Countershock ,food and beverages ,Arrhythmias, Cardiac ,Review ,Defibrillators, Implantable ,Electrocardiography ,Treatment Outcome ,Heart Conduction System ,Recurrence ,cardiovascular system ,Catheter Ablation ,Humans ,cardiovascular diseases ,Anti-Arrhythmia Agents - Abstract
Electrical storm is an increasingly common and life-threatening syndrome that is defined by 3 or more sustained episodes of ventricular tachycardia, ventricular fibrillation, or appropriate shocks from an implantable cardioverter-defibrillator within 24 hours. The clinical presentation can be dramatic. Electrical storm can manifest itself during acute myocardial infarction and in patients who have structural heart disease, an implantable cardioverter-defibrillator, or an inherited arrhythmic syndrome. The presence or absence of structural heart disease and the electrocardiographic morphology of the presenting arrhythmia can provide important diagnostic clues into the mechanism of electrical storm. Electrical storm typically has a poor outcome.The effective management of electrical storm requires an understanding of arrhythmia mechanisms, therapeutic options, device programming, and indications for radiofrequency catheter ablation. Initial management involves determining and correcting the underlying ischemia, electrolyte imbalances, or other causative factors. Amiodarone and β-blockers, especially propranolol, effectively resolve arrhythmias in most patients. Nonpharmacologic treatment, including radiofrequency ablation, can control electrical storm in drug-refractory patients. Patients who have implantable cardioverter-defibrillators can present with multiple shocks and may require drug therapy and device reprogramming. After the acute phase of electrical storm, the treatment focus should shift toward maximizing heart-failure therapy, performing revascularization, and preventing subsequent ventricular arrhythmias. Herein, we present an organized approach for effectively evaluating and managing electrical storm.
- Published
- 2011
7. Pharmacologic Management of Arrhythmias
- Author
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Ganjehei, Leila, Massumi, Ali, Nazeri, Alireza, and Razavi, Mehdi
- Subjects
Twelfth Symposium on Cardiac Arrhythmias ,Treatment Outcome ,Heart Conduction System ,Potassium Channel Blockers ,Humans ,Arrhythmias, Cardiac ,Anti-Arrhythmia Agents ,Sodium Channel Blockers - Published
- 2011
8. Cardiac Arrhythmias in Women
- Author
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Ganjehei, Leila, Massumi, Ali, Nazeri, Alireza, and Razavi, Mehdi
- Subjects
Male ,Pregnancy Complications, Cardiovascular ,Age Factors ,Arrhythmias, Cardiac ,Health Status Disparities ,Middle Aged ,Prognosis ,Sex Factors ,Heart Conduction System ,Pregnancy ,Cardiovascular Disease in Women ,Child, Preschool ,Humans ,Women's Health ,Female ,Gonadal Steroid Hormones ,Aged - Published
- 2011
9. Antiarrhythmic Therapy in Atrial Fibrillation.
- Author
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Barekatain, Armin and Razavi, Mehdi
- Subjects
- *
MYOCARDIAL depressants , *ATRIAL fibrillation treatment , *BIOCHEMICAL mechanism of action , *PHARMACODYNAMICS , *THERAPEUTICS , *HEART diseases , *FLECAINIDE , *PROPAFENONE - Abstract
The article discusses the use of antiarrhythmic agents in the treatment of atrial fibrillation. Information on the mechanism of action of these drugs is provided. Flecainide is a class I antiarrhythmic agent that has a use-dependence effect. Droneradone can block multiple ion channels and has sympatholytic effects. Recommended first-line therapy for patients with no or minimal structural heart disease are flecainide, propafenone and dronedarone.
- Published
- 2012
10. Cardiac Resynchronization Therapy.
- Author
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Ganjehei, Leila, Razavi, Mehdi, and Massumi, Ali
- Subjects
- *
IMPLANTABLE cardioverter-defibrillators , *ARRHYTHMIA prevention , *LEFT heart ventricle , *CONTRACTILITY (Biology) , *HEMODYNAMICS - Abstract
The article focuses on the benefits of combining cardiac resynchronization therapy (CRT) device with an implantable cardiac defibrillator (ICD) as a protection against arrhythmias and leads to survival from all-cause death. CRT uses standard dual-chamber pacing leads with a third lead implanted via the coronary sinus and positioned in a cardiac vein to pace the left ventricle (LV). The CRT hemodynamic benefits result from synchronization of LV and right ventricle (RV) contractility.
- Published
- 2011
11. Catheter-Based Ablation of Atrial Fibrillation.
- Author
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Ganjehei, Leila, Razavi, Mehdi, and Rasekh, Abdi
- Subjects
- *
CATHETER ablation , *ATRIAL fibrillation treatment , *ARRHYTHMIA treatment , *ECHOCARDIOGRAPHY , *PULMONARY veins - Abstract
The article discusses catheter-based radiofrequency ablation as a treatment for atrial fibrillation (AF), a common sustained cardiac arrhythmia. AF is caused by a rapidly firing focus in one of the atria which maintains the AF through short reentrant circuits thereby, causing spiraling fibrillatory conduction. Whether the technique used is Lasso, double Lasso or intracardiac echocardiogram-guided, isolation of the pulmonary veins (PVs) is the cornerstone of an ablation approach.
- Published
- 2011
12. Safe and Effective Pharmacologic Management of Arrhythmias.
- Author
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Razavi, Mehdi
- Subjects
- *
ARRHYTHMIA treatment , *HEART diseases , *SODIUM channels , *POTASSIUM channels , *CHEMICAL inhibitors - Abstract
Focuses on two common classes of antiarrhythmic medications that affect the depolarization and repolarization of the myocardial cell. Condition of the health of the patients who can use the class I antiarrhythmics; Agents that can block the sodium channel; Efficiency of the class II agents in blocking the potassium channel.
- Published
- 2005
13. Cardiac Arrhythmias During Pregnancy.
- Author
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Safavi-Naeini, Payam, Sorurbakhsh, Naseem Zarah, and Razavi, Mehdi
- Published
- 2021
- Full Text
- View/download PDF
14. Platypnea-Orthodeoxia Syndrome Caused by an Intracardiac Shunt.
- Author
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Borgaonkar, Sanket P., Lam, Wilson W., Razavi, Mehdi, and Parekh, Dhaval R.
- Subjects
- *
ATRIAL septal defects , *DIAGNOSIS , *TRICUSPID valve insufficiency , *LUNG diseases , *PLATYPNEA orthodeoxia syndrome - Abstract
Platypnea-orthodeoxia syndrome, a rare condition characterized by posture-related dyspnea, is usually caused by an intracardiac shunt, hepatopulmonary syndrome, or shunting resulting from severe pulmonary disease. We report the case of a 33-year-old woman who presented with increasing dyspnea and oxygen desaturation when she sat up or arose. Our diagnosis was platypnea-orthodeoxia syndrome. A lead of a previously implanted pacemaker exacerbated a severe tricuspid regurgitant jet that was directed toward the patient's intra-atrial septum. Percutaneous closure of a small secundum atrial septal defect eliminated right-to-left shunting and substantially improved the patient's functional status. In addition to this case, we discuss this unusual condition. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
15. Anesthetic Management in Radiofrequency Catheter Ablation of Ventricular Tachycardia.
- Author
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Deng, Yi, Naeini, Payam S., Razavi, Mehdi, Collard, Charles D., Tolpin, Daniel A., and Anton, James M.
- Subjects
- *
CATHETER ablation , *VENTRICULAR tachycardia , *ELECTROPHYSIOLOGY , *SURGICAL complications , *PATHOLOGICAL physiology - Abstract
Radiofrequency catheter ablation is increasingly being used to treat patients who have ventricular tachycardia, and anesthesiologists frequently manage their perioperative care. This narrative review is intended to familiarize anesthesiologists with preprocedural, intraprocedural, and postprocedural implications of this ablation. Ventricular tachycardia typically arises from structural heart disease, most often from scar tissue after myocardial infarction. Many patients thus affected will benefit from radiofrequency catheter ablation in the electrophysiology laboratory to ablate the foci of arrhythmogenesis. The pathophysiology of ventricular tachycardia is complex, as are the technical aspects of mapping and ablating these arrhythmias. Patients often have substantial comorbidities and tenuous hemodynamic status, necessitating pharmacologic and mechanical cardiopulmonary support. General anesthesia and monitored anesthesia care, when used for sedation during ablation, can lead to drug interactions and side effects in the presence of ventricular tachycardia, so anesthesiologists should also be aware of potential perioperative complications. We discuss variables that can help anesthesiologists safely guide patients through the challenges of radiofrequency catheter ablation of ventricular tachycardia. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
16. What's New in Anticoagulation.
- Author
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Razavi, Joanna Esther Molina, Safavi-Naeini, Payam, and Razavi, Mehdi
- Subjects
- *
ATRIAL fibrillation treatment , *ATRIAL fibrillation prevention , *ARRHYTHMIA treatment , *DRUG therapy , *WARFARIN , *DABIGATRAN , *RIVAROXABAN , *THERAPEUTICS - Abstract
The article discusses dugs used for treatment of atrial fibrillation (AF) which is most prevalent type of arrhythmia and affects an estimated 2.7 to 6.1 million people in the U.S. It mentions drugs such as Warfarin in preventing AF-related strokes, Dabigatran as direct thrombin inhibitor and Rivaroxaban as an oral, direct factor Xa inhibitor.
- Published
- 2016
- Full Text
- View/download PDF
17. Artificial Intelligence and Machine Learning in Cardiac Electrophysiology.
- Author
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John, Mathews M., Banta, Anton, Post, Allison, Buchan, Skylar, Aazhang, Behnaam, and Razavi, Mehdi
- Abstract
Cardiac electrophysiology requires the processing of several patient-specific data points in real time to provide an accurate diagnosis and determine an optimal therapy. Expanding beyond the traditional tools that have been used to extract information from patient-specific data, machine learning offers a new set of advanced tools capable of revealing previously unknown data patterns and features. This new tool set can substantially improve the speed and level of confidence with which electrophysiologists can determine patient-specific diagnoses and therapies. The ability to process substantial amounts of data in real time also paves the way to novel techniques for data collection and visualization. Extended realities such as virtual and augmented reality can now enable the real-time visualization of 3-dimensional images in space. This enables improved preprocedural planning and intraprocedural interventions. Machine learning supplemented with novel visualization technologies could substantially improve patient care and outcomes by helping physicians to make more informed patient-specific decisions. This article presents current applications of machine learning and their use in cardiac electrophysiology. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Tachycardia-Mediated Cardiomyopathy.
- Author
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Bensler, James Michael, Frank, Christopher M., Razavi, Mehdi, Rasekh, Abdi, Saeed, Mohammad, Haas, Phillip C., Nazeri, Alireza, and Massumi, Ali
- Subjects
- *
TACHYCARDIA , *ATRIOVENTRICULAR node , *VENTRICULAR tachycardia , *CONGESTIVE heart failure , *CARDIOMYOPATHIES - Abstract
Permanent junctional reciprocating tachycardia, or atrioventricular reentrant tachycardia utilizing a slowly conducting posteroseptal accessory pathway, is a rare form of reentrant supraventricular tachycardia in children and adults. The characteristic features of this narrow complex tachycardia are a long RP interval and inverted P waves in the inferior leads. This form of accessory-pathway-mediated tachycardia, which is usually incessant, can lead to a tachycardia-induced cardiomyopathy and congestive heart failure if left untreated. Radiofrequency ablation of the accessory pathway in permanent junctional reciprocating tachycardia is the definitive treatment in these patients, and in many instances the effects of prolonged tachycardia on ventricular function are reversible after successful ablation. We present an illustrative case. [ABSTRACT FROM AUTHOR]
- Published
- 2010
19. Alcohol Ablation of Cardiac Tissues Quantified and Evaluated Using CIELAB Euclidean Distances.
- Author
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Rook, Ashley, John, Mathews M., Post, Allison, and Razavi, Mehdi
- Subjects
- *
EUCLIDEAN distance , *TWO-way analysis of variance , *ALCOHOL , *LEFT heart atrium , *TISSUES - Abstract
Ethanol solubilizes cell membranes, making it useful for various ablation applications. We examined the effect of time and alcohol type on the extent of ablation, quantified as Euclidean distances between color coordinates. We obtained biopsy punch samples (diameter, 6 mm) of left atrial appendage, atrial, ventricular, and septal tissue from porcine hearts and placed them in transwell plates filled with ethanol or methanol for 10, 20, 30, 40, 50, or 60 min. Control samples were taken for each time point. At each time point, samples were collected, cut transversely, and photographed. With use of a custom MATLAB program, all images were analyzed in the CIELAB color space, which is more perceptually uniform than the red-green-blue color space. Euclidean distances were calculated from CIELAB coordinates. The mean and standard error of these distances were analyzed. Two-way analysis of variance was used to test for differences among time points, and 2-tailed t tests, for differences between the alcohol datasets at each time point. Generally, Euclidean distances differed significantly between all time points, except for those immediately adjacent, and methanol produced larger Euclidean distances than ethanol did. Some tissue showed a plateauing effect, potentially indicating transmurality. Mean Euclidean distances effectively indexed alcohol ablation in cardiac tissue. Furthermore, we found that methanol ablated tissue more effectively than ethanol did. With ethanol, the extent of ablation for atrial tissue was largest at 60 min. We conclude that to achieve full transmurality in clinical applications, ethanol must remain in contact with atrial tissue for at least one hour. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
20. Comparative Efficacy of Nebivolol and Metoprolol to Prevent Tachycardia-Induced Cardiomyopathy in a Porcine Model.
- Author
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Nazeri, Alireza, Elayda, MacArthur A., Segura, Ana Maria, Stainback, Raymond F., Nathan, Joanna, Lee, Vei-Vei, Bove, Christina, Sampaio, Luiz, Grace, Brian, Massumi, Ali, and Razavi, Mehdi
- Subjects
- *
CLINICAL trials , *TACHYCARDIA treatment , *NEBIVOLOL hydrochloride , *METOPROLOL , *MYOCARDIAL depressants , *THERAPEUTICS - Abstract
Chronic tachycardia is a well-known cause of nonischemic cardiomyopathy. We hypothesized that nebivolol, a β-blocker with nitric oxide activity, would be superior to a pure β-blocker in preventing tachycardia-induced cardiomyopathy in a porcine model. Fifteen healthy Yucatan pigs were randomly assigned to receive nebivolol, metoprolol, or placebo once a day. All pigs underwent dual-chamber pacemaker implantation. The medication was started the day after the pacemaker implantation. On day 7 after implantation, each pacemaker was set at atrioventricular pace (rate, 170 beats/min), and the pigs were observed for another 7 weeks. Transthoracic echocardiograms, serum catecholamine levels, and blood chemistry data were obtained at baseline and at the end of the study. At the end of week 8, the pigs were euthanized, and complete histopathologic studies were performed. All the pigs developed left ventricular cardiomyopathy but remained hemodynamically stable and survived to the end of the study. The mean left ventricular ejection fraction decreased from baseline by 34%, 20%, and 20% in the nebivolol, metoprolol, and placebo groups, respectively. These changes did not differ significantly among the 3 groups ( P =0.51). Histopathologic analysis revealed mild left ventricular perivascular fibrosis with cardiomyocyte hypertrophy in 14 of the 15 pigs. Both nebivolol and metoprolol failed to prevent cardiomyopathy in our animal model of persistent tachycardia and a high catecholamine state. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. Orthostatic Hypotension.
- Author
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Ganjehei, Leila, Massumi, Ali, Razavi, Mehdi, and Wilson, James M.
- Subjects
- *
ORTHOSTATIC hypotension , *VITAMIN B12 , *VITAMIN deficiency , *VITAMIN B12 deficiency , *HYPERTENSION , *THERAPEUTICS - Abstract
A 90-year-old woman with orthostatic hypotension and near-syncope was found to have a low-normal level of vitamin B12 and no other medical findings that could explain her orthostasis. Her symptoms responded to vitamin B12 replacement therapy. This case shows that vitamin B12 deficiency can induce orthostatic hypotension and syncope that are correctable by vitamin B12 replacement. (Tex Heart Inst J 2012;39(5):722-3) [ABSTRACT FROM AUTHOR]
- Published
- 2012
22. Biventricular Intracardiac Device.
- Author
-
Ganjehei, Leila, Barekatain, Armin, Razavi, Mehdi, Massumi, Ali, and Rasekh, Abdi
- Subjects
- *
HEART diseases , *IMPLANTABLE cardioverter-defibrillators , *ANGIOGRAPHY , *CARDIAC catheterization , *LEFT heart ventricle - Abstract
The article discusses the case of a 66-year-old man with acute-on-chronic systolic dysfunction who underwent cardiac resynchronization therapy with a biventricular implantable cardiac defibrillator. His medical history included congestive heart failure and ischemic cardiomyopathy. A persistent left superior vena cava was detected via contrast angiography. He returned to the cardiac catheterization laboratory a day following the procedure due to a loss of capture of the left ventricle lead.
- Published
- 2012
23. Abdominal Fat Suspension Device for Maintaining Normal Cardiorespiratory Function in Patients Undergoing Conscious Sedation during Surgery: A Feasibility Study.
- Author
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Truong, Norman F., Nathan, Joanna C., Daeun Yoon, Ochoa, Gabriel, Prevost, Marisa, Yun, Sehyun, Oden, Z. Maria, and Razavi, Mehdi
- Subjects
- *
OVERWEIGHT persons , *SURGERY , *ABDOMINAL adipose tissue , *SURGICAL instruments , *HEART beat - Abstract
Obese patients undergoing conscious-sedation surgery have increased perioperative morbidity because their excess abdominal tissue limits diaphragmatic excursion. We describe a simple device that might help attenuate this risk. We created a noninvasive suction device for abdominal suspension. By lifting the burden of excess weight, this device should decrease respiratory effort. To test the feasibility of excess weight removal in relieving cardiac stress, we tested 22 supine, healthy, normal-weight subjects by measuring their heart rates with and without a 13-kg tissue model on their abdomen to simulate excess weight. There was no significant difference in blood oxygen saturation before and after weight removal (P=0.318). However, the decrease in heart rate was significant (P <0.0001; paired 2-sample, one-tailed t test), which implies decreased respiratory effort. This result suggests the possibility that abdominal mass suspension in obese patients is associated with decreased respiratory effort. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
24. Heterogeneity of Left Ventricular Signal Characteristics.
- Author
-
Nazeri, Alireza, Elayda, MacArthur A., Dragnev, Lubomir, Frank, Christopher M., Jihong Qu, Afonso, Valtino X., Rasekh, Abdi, Saeed, Mohammad, Jie Cheng, Shuraih, Mossaab, Massumi, Ali, and Razavi, Mehdi
- Subjects
- *
VENTRICULAR fibrillation , *NEURAL stimulation , *HEART ventricles , *MYOCARDIUM , *ELECTRODES , *LABORATORY dogs - Abstract
Studies have shown that long-term vagal stimulation is protective against ventricular fibrillation; however, the effects of acute vagal stimulation during ventricular fibrillation in the normal heart have not been investigated. We examined the effects of acute vagal stimulation on ventricular fibrillation in a canine model. In 4 dogs, we induced 30-second periods of ventricular fibrillation by means of intraventricular pacing. During 2 of the 4 periods of fibrillation that we analyzed, vagal stimulation was delivered through electrodes in the caudal ends of the vagus nerves. Noncontact unipolar electrograms were recorded from 3 ventricular regions: the basal septum, apical septum, and lateral free wall. We then computed the most frequent cycle length, mean organization index, and mean electrogram amplitude for each region. During fibrillation, vagal stimulation shortened the most frequent cycle lengths in the basal septum (P=0.02) and apical septum (P=0.0001), but not in the lateral wall (P=0.46). In addition, vagal stimulation significantly reduced the mean organization indices in the apical septum (P <0.001) and lateral wall (P <0.001), but not in the basal septum (P=0.19). Furthermore, vagal stimulation raised the mean electrogram amplitude in the basal septum (P <0.01) but lowered it substantially in the apical septum (P=0.00005) and lateral wall (P=0.00003). We conclude that vagal stimulation acutely affects the characteristics of ventricular fibrillation in canine myocardium in a spatially heterogeneous manner. This nonuniformity of response may have implications with regard to manipulating the autonomic system as a means of modifying the substrate for ventricular dysrhythmias. [ABSTRACT FROM AUTHOR]
- Published
- 2011
25. Inherited Arrhythmic Disorders.
- Author
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Nader, Amirali, Massumi, Ali, Jie Cheng, and Razavi, Mehdi
- Subjects
- *
GENETIC disorders , *ARRHYTHMIA , *ETIOLOGY of diseases , *HEART diseases , *HEART beat , *CARDIAC arrest , *BIOCHEMISTRY , *DRUG therapy - Abstract
Inherited arrhythmic disorders comprise a group of syndromes with unique genetic abnormalities and presentations but with very similar clinical outcomes and complications, the most terrifying of which are life-threatening arrhythmias and sudden cardiac death. Advances in molecular biology have enabled us to define and pinpoint many such disorders, which were previously labeled as idiopathic, to specific genes on various chromosomes. The current trend in the management of these potentially deadly disorders is to use pharmacotherapy (antiarrhythmic agents) and defibrillators for the prevention of sudden death; however, targeted therapy at a molecular level appears to be the path of the future. Herein, we review long QT and Brugada syndromes and focus on the genetics, pathophysiology, and clinical manifestations of these inherited arrhythmogenic disorders that affect patients with structurally normal hearts. [ABSTRACT FROM AUTHOR]
- Published
- 2007
26. Marked Attenuation of Shock Burden.
- Author
-
Ganjehei, Leila, Nazeri, Alireza, Massumi, Ali, and Razavi, Mehdi
- Subjects
- *
IMPLANTABLE cardioverter-defibrillators , *CARDIOMYOPATHIES , *TACHYCARDIA , *VENTRICULAR tachycardia - Abstract
A 76-year-old man was admitted to our institution for elective exchange of his implanted cardioverter-defibrillator generator. Nine years earlier, he had been diagnosed with nonischemic cardiomyopathy and nonsustainable ventricular tachycardia. At that time, he had received a single-chamber implanted cardioverter-defibrillator, which was upgraded to a dual-chamber implanted cardioverter-defibrillator 3 years later. In the course of the current admission, routine device interrogation during exchange of the patient's implanted cardioverter-defibrillator generator revealed 150 episodes of ventricular tachycardia in the preceding 7 months, 137 of which had been successfully treated by antitachycardia pacing therapy without shock. These findings show the remarkable effectiveness of antitachycardia pacing in terminating ventricular tachycardia while preventing the delivery of shocks, minimizing patient discomfort, and avoiding implanted cardioverter-defibrillator battery depletion. [ABSTRACT FROM AUTHOR]
- Published
- 2012
27. Migraine and Vasodepressor Syncope in a Large Family.
- Author
-
Paisley, Robert D., Arora, Harvinder S., Nazeri, Alireza, Massumi, Ali, and Razavi, Mehdi
- Subjects
- *
FAMILIAL diseases , *VASCULAR diseases - Abstract
We evaluated a 47-year-old woman for recurrent migraine and syncope. The patient had 7 children (not examined by the authors), all of whom also experienced migraine and syncope. The patient's father, now deceased, had reportedly experienced migraine and episodes of feeling faint. All 5 of the patient's siblings reported migraine, and 4 of the 5 reported syncope. The case of our patient, which we discuss herein, suggests a genetic link between these 2 conditions, both of which include vascular dysregulation in their pathogenesis. To our knowledge, the medical literature contains no previous description of familial associations of combined migraine and syncope. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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