Publications by authors named "Ali Massumi"

52 Publications

Swallowing-induced Supraventricular Tachyarrhythmia.

Rev Cardiovasc Med 2017;18(1):53-58

Nerve and Muscle Center of Texas, Houston, TX.

Swallowing-induced supraventricular tachyarrhythmia is an extremely rare entity with unclear pathophysiology. A 55-year-old man presented with a 2-year history of worsening presyncopal symptoms triggered only by drinking liquids of any temperature. Results of a physical examination were unremarkable except for reproducible atrial tachycardias to 180 to 210 beats/minute documented on rhythm strips when the patient was given water to drink. He underwent radiofrequency ablation with complete resolution of symptoms. We reviewed all 43 published cases of swallowing-induced supraventricular tachyarrhythmia in the English-language medical literature. We found only one other reported case induced only by drinking liquids. Radiofrequency ablation appears to be the treatment of choice.
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July 2019

Effect of botulinum toxin on inducibility and maintenance of atrial fibrillation in ovine myocardial tissue.

Pacing Clin Electrophysiol 2017 Jun 16;40(6):693-702. Epub 2017 May 16.

Department of Cardiology, Texas Heart Institute, Houston, Texas.

Background: Aberrant vagal stimulation may promote the generation and propagation of atrial fibrillation (AF). Researchers have suggested that botulinum toxin (BTX), a neurotoxin that decreases neural vagal stimulation, may decrease the incidence of postoperative AF. The exact electrophysiologic mechanism underlying the observations and histopathologic alterations associated with BTX are unclear.

Objective: To investigate the electrophysiologic, functional, and histopathologic effects of BTX on fibrillation induction in ovine atria.

Methods: Eight sheep underwent BTX injections into their pulmonary veins, atrial fat pads, and ventricular walls. Electrophysiology with pacing was performed at baseline and 7 days after injection to evaluate the atrial effective refractory period (ERP) and vulnerability to AF with and without vagal stimulation. Echocardiography was performed at baseline and day 7. After euthanasia, histopathologic analysis was performed.

Results: Seven sheep completed the study. For both atria, there was significant shortening in the ERP with vagal stimulation versus no stimulation on day 0 but not on day 7. More aggressive pacing was required to induce AF in the left atrium on day 7 than on day 0. Echocardiography on day 7 showed no significant changes in ejection fraction or new wall-motion abnormalities of the left and right ventricle. Histopathologic analysis showed no significant adverse effects.

Conclusion: The subacute BTX effect reduced the vulnerability of atrial tissue to AF induction and reduced the vagal influence on atrial ERP shortening compared to baseline levels. Direct BTX injection did not cause myocardial dysfunction or histologic adverse effects.
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http://dx.doi.org/10.1111/pace.13079DOI Listing
June 2017

Comparative Efficacy of Nebivolol and Metoprolol to Prevent Tachycardia-Induced Cardiomyopathy in a Porcine Model.

Tex Heart Inst J 2016 Dec 1;43(6):477-481. Epub 2016 Dec 1.

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 ( =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.
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http://dx.doi.org/10.14503/THIJ-15-5495DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5179150PMC
December 2016

Left Atrial Appendage Ligation in Nonvalvular Atrial Fibrillation Patients at High Risk for Embolic Events With Ineligibility for Oral Anticoagulation: Initial Report of Clinical Outcomes.

JACC Clin Electrophysiol 2015 Dec 22;1(6):465-474. Epub 2015 Oct 22.

Department of Medicine and Cardiovascular Research Center, University of California, San Francisco, California. Electronic address:

Objectives: This study sought to assess long-term clinical outcomes in adults with nonvalvular atrial fibrillation (AF) who are ineligible for oral anticoagulation therapy and underwent left atrial appendage (LAA) ligation with the Lariat device.

Background: LAA exclusion has been used to prevent thrombus formation within the LAA in AF patients and is believed to decrease the risk of cardioembolic events.

Methods: LAA ligation with the Lariat device was performed in 139 patients with nonvalvular AF. LAA closure was verified during the procedure by LA angiography and transesophageal echocardiography. A follow-up transesophageal echocardiography was performed at 30 to 45 days post-procedure. After the procedure, patients received aspirin only, clopidogrel only, aspirin plus clopidogrel, or no antithrombotic drugs. Patients did not receive transition oral anticoagulation therapy post-LAA ligation. Patients were followed for LAA closure and adverse events, including stroke, systemic events, and death.

Results: Acute closure was accomplished in 138 of 139 treated patients (99%). In 1 patient, a posterior lobe was partially closed. At the day-30 to day-45 transesophageal echocardiography (n = 127), 114 (90%) had complete LAA closure, and 13 (10%) had a 2- to 4-mm leak. There were no leaks ≥5 mm. The periprocedural adverse event rate was 11.5%, including 2 cardiac perforations and 1 death due to pulmonary embolus. Over a mean follow-up of 2.9 ± 1.1 years, the event rate for the composite endpoint of stroke and systemic embolism was 1.0% per year (n = 4). The combined stroke, embolism, and death of any cause event rate was 2.8% (n = 11) per year.

Conclusions: The findings from this analysis of post-procedure event rates suggest that LAA ligation with the Lariat device effectively closes the LAA and may be a beneficial approach to reduce the risk of embolic events in AF patients ineligible to oral anticoagulation therapy. However, future randomized clinical trials are needed to verify these results and to determine device and procedural safety.
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http://dx.doi.org/10.1016/j.jacep.2015.08.005DOI Listing
December 2015

A Review of the LARIAT Suture Delivery Device for Left Atrial Appendage Closure.

J Tehran Heart Cent 2015 Apr;10(2):69-73

Department of Cardiology, Texas Heart Institute, Houston, Texas, USA.

The prevalence of atrial fibrillation (AF) is 1-2 % in the general population, and the risk of embolic stroke in AF patients is 4-5 times higher than that in the general population. AF-related strokes are often severe, and the rate of permanent disability is much higher among individuals who have AF-related strokes than in those who have strokes unrelated to AF. In patients with AF, more than 90 % of thrombi originate from the left atrial appendage (LAA). The purpose of this paper is to review the efficacy and safety of performing the LAA closure with the LARIAT Suture Delivery Device to prevent AF-related stroke in patients with contraindications to oral anticoagulant therapy.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4477089PMC
April 2015

Endocardial (Watchman) vs epicardial (Lariat) left atrial appendage exclusion devices: Understanding the differences in the location and type of leaks and their clinical implications.

Heart Rhythm 2015 Jul 14;12(7):1501-7. Epub 2015 Mar 14.

Division of Cardiovascular Diseases, Cardiovascular Research Institute, University of Kansas Hospital & Medical Center, Kansas City, Kansas. Electronic address:

Background: Watchman and Lariat left atrial appendage (LAA) occlusion devices are associated with LAA leaks postdeployment.

Objective: The purpose of this study was to compare the incidence, characteristics, and clinical significance of these leaks.

Methods: We performed a multicenter prospective observational study of all patients who underwent LAA closure. Baseline, procedural, and imaging variables along with LAA occlusion rates at 30-90 days and 1-year postprocedure were compared.

Results: A total of 478 patients (219 with the Watchman device and 259 with the Lariat device) with successful implants were included. Patients in the Lariat group had a higher CHADS2 (congestive heart failure, hypertension, age >74 years, diabetes, stroke) score and a larger left atrium and LAA. A total of 79 patients (17%) had a detectable leak at 1 year. More patients in the Watchman group had a leak compared with those in the Lariat group (46 [21%] vs 33 [14%]; P = .019). All the leaks were eccentric (edge effect) in the Watchman group and concentric (gunny sack effect) in the Lariat group. The size of the leak was larger in the Watchman group than in the Lariat group (3.10 ± 1.5 mm vs 2.15 ± 1.3 mm; P = .001). The Watchman group had 1 device embolization requiring surgery and 2 pericardial effusions requiring pericardiocentesis. In the Lariat group, 4 patients had cardiac tamponade requiring urgent surgical repair. Three patients in each group had a cerebrovascular accident and were not associated with device leaks.

Conclusion: The Lariat device is associated with a lower rate of leaks at 1 year as compared with the Watchman device, with no difference in rates of cerebrovascular accident. There was no correlation between the presence of residual leak and the occurrence of cerebrovascular accident.
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http://dx.doi.org/10.1016/j.hrthm.2015.03.020DOI Listing
July 2015

Safety and effectiveness of compassionate use of LARIAT® device for epicardial ligation of anatomically complex left atrial appendages.

J Interv Card Electrophysiol 2015 Jan 17;42(1):11-9. Epub 2015 Jan 17.

Texas Heart Institute/Baylor CHI St. Luke Health System, 6770 Bertner Street, MC 2-255, Houston, TX, 77030, USA.

Background: Percutaneous left atrial appendage (LAA) ligation using an epicardial suture system (LARIAT®, SentreHEART, Palo Alto, CA) has been used in patients with nonvalvular atrial fibrillation (AF) and contraindication to oral anticoagulation. However, complex LAA anatomy may preclude its use. We report the safety and effectiveness of compassionate use of first-generation LARIAT® device for epicardial ligation of large, complex left atrial appendages.

Methods: Between January 2010 and March 2013, 93 patients with AF, high CHADS2 score, and contraindication(s) for oral anticoagulation therapy were evaluated for LAA ligation. Complex anatomy detected by 3D cardiac computed tomography CT angiography led to preclusion of 25 patients (27%). Of these, nine patients who opted for epicardial LAA ligation on compassionate grounds were studied.

Results: Mean age was 68.1 ± 8.2 years, four females, all with large LAA width (>40 mm, 45-58 mm) and additional anatomic complexities such as bilobed (two), long C-shaped-like (two), goose neck-like (one), multilobed cauliflower-like (two), cactus-like (one), and chicken wing-like (one) LAA. LAA ligation with LARIAT® was successfully performed with surgical standby in all patients. Seven patients (78%) were safely treated percutaneously and only two patients required minimally invasive thoracotomy (one due to inability to release the epicardial snare from long C-shaped LAA and other due to preexisting adhesions precluding pericardial entry). There were no major complications. Repeat trans-esophageal echocardiography at 3 months showed no remnant flow and none had stroke off Coumadin at 19.3 ± 8.2 months of follow-up.

Conclusions: Despite a high preclusion rate, percutaneous LAA ligation may be safely and effectively performed on compassionate grounds using the first-generation LARIAT® device with surgical standby in patients with large and complex LAA.
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http://dx.doi.org/10.1007/s10840-014-9963-2DOI Listing
January 2015

Cryoballoon pressure waveform change during balloon inflation is not a reliable predictor of adequate pulmonary vein occlusion.

Pacing Clin Electrophysiol 2014 Dec;37(12):1702-7

Background: Cryoballoon ablation of pulmonary veins (PVs) is widely used to treat atrial fibrillation (AF). Successful ablation requires occluding the PVs by cryoballoon. Angiography is a standard method of assessing PV occlusion. To decrease contrast doses and overcome potential contraindications (e.g., allergy to contrast, renal disease), alternative methods have been tested, including intracardiac echocardiography, transesophageal echocardiography-color flow Doppler, and distal cryoballoon pressure monitoring.

Objective: We evaluated pressure monitoring’s accuracy in detecting PV occlusion during cryoballoon ablation.

Methods: We studied 72 PVs in 18 nonconsecutive patients (mean age 68 ± 8 years; 13 male) who underwent cryoballoon ablation for paroxysmal AF. In 67 PVs, we documented the point at which the recorded pressure waveform at the distal tip of the inflated cryoballoon transformed from a left atrial into a pulmonary arterial pressure waveform. PV occlusion was confirmed by concurrent PV angiography through the distal balloon channel. Occlusion was rated on a I–IV scale in which I indicated poor occlusion with major leakage and IV indicated complete occlusion without leakage.

Results: In 43 of 67 PVs (64%), the change in the pressure waveform from left atrial to pulmonary arterial was associated with complete PV occlusion (grade IV), confirmed by angiography. In the other 24 PVs, complete occlusion was achieved by further movement of the cryoballoon under intracardiac echocardiographic guidance and angiographic confirmation. All 67 PVs were electrically isolated with cryoballoon.

Conclusions: The change in pressure waveforms at the distal tip of inflated cryoballoon is not a reliable predictor of complete PV occlusion during cryoballoon ablation.
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http://dx.doi.org/10.1111/pace.12491DOI Listing
December 2014

Contact-force recovery can predict cardiac perforation during radiofrequency ablation.

Pacing Clin Electrophysiol 2014 Sep 4;37(9):1129-32. Epub 2014 May 4.

Department of Cardiology, Texas Heart Institute, Houston, Texas.

Background: During radiofrequency ablation (RFA), the ability to know whether a steam pop has led to cardiac perforation (CP) would be of profound clinical significance. We aimed to determine whether catheter contact-force characteristics can predict whether a steam pop during RFA causes CP.

Methods: We used a 7.5F Thermocool® Smarttouch™ force-sensing catheter (Biosense Webster Inc., Diamond Bar, CA, USA) to perform open-chest left atrial RFA under direct visualization in four sheep. We measured the contact force and its direction every 50 ms during RFA. At each steam pop, we noted whether CP occurred. We then analyzed the contact-force signals to determine whether specific features predicted the presence (+) or absence (-) of CP.

Results: A total of 24 steam pops occurred; 10 were CP+ and 14 were CP-. At the time of CP+ and CP- events, the contact force was 50 ± 25 and 40 ± 15 g, respectively (P = 0.146). All steam-pop events were associated with a rapid drop-off in contact force, but 10 of the 14 CP- events showed an immediate contact-force rebound, whereas none of the CP+ events did. This rebound presumably occurred as the catheter tip resumed contact with the left atrial wall. The average contact-force rebound equaled 80-100% of the contact-force drop-off.

Conclusions: The ability to measure catheter contact force during RFA is a valuable asset, as contact-force recovery may be used to predict CP. Further studies are warranted to validate our findings in the clinical setting.
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http://dx.doi.org/10.1111/pace.12409DOI Listing
September 2014

Initial experience with a novel percutaneous left atrial appendage exclusion device in patients with atrial fibrillation, increased stroke risk, and contraindications to anticoagulation.

Am J Cardiol 2013 Mar 9;111(6):869-73. Epub 2013 Jan 9.

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX, USA.

Atrial fibrillation (AF) increases by fivefold a patient's risk for thromboembolic stroke. The main source of emboli in AF is the left atrial appendage (LAA). Therefore, LAA closure could reduce the risk for thromboembolic events in AF. The investigators report the first United States experience with a novel percutaneous LAA closure device, the Lariat snare device, and its outcomes in 21 patients with AF, CHADS2 scores ≥2, and contraindications to anticoagulation. The LAA was closed with a snare containing suture from within the pericardial space. The intraoperative success of the procedure was confirmed by left atrial angiography and transesophageal echocardiographic color Doppler flow. The effectiveness of the procedure was evaluated by follow-up transesophageal echocardiography. The incidence of periprocedural and short-term complications was assessed by reviewing medical records. Twenty patients (100%) had successful LAA exclusion that was preserved at 96 ± 77 days. No patient had a stroke during an average of 352 ± 143 days of follow-up. One patient had right ventricular perforation and tamponade that required surgical exploration and repair. Two patients required prolonged hospitalization: 1 because of pericardial effusion that required repeat pericardiocentesis and 1 because of noncardiac co-morbidities. Three patients developed pericarditis <1 month after the procedure, of whom 1 had associated pericardial effusion that required drainage. In conclusion, percutaneous LAA exclusion can be achieved successfully and with an acceptable incidence of periprocedural and short-term complications. Further studies are needed to determine whether LAA exclusion lowers the long-term risk for thromboembolic events in patients with AF and contraindications to anticoagulation.
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http://dx.doi.org/10.1016/j.amjcard.2012.11.061DOI Listing
March 2013

Fistula from right internal mammary artery to superior vena cava after use of a laser sheath to extract a pacemaker lead.

Tex Heart Inst J 2012 ;39(5):727-30

Department of Adult Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

A 55-year-old woman presented with dyspnea on exertion due to a right internal mammary artery-to-superior vena cava arteriovenous fistula that occurred after pacemaker lead extraction with a laser sheath. The fistula was successfully repaired by placing a covered stent in the right internal mammary artery. In this unusual location, endovascular stenting is a reasonable alternative to coil embolization or surgical repair of an arteriovenous fistula resulting from laser lead extraction.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3461661PMC
April 2013

Orthostatic hypotension as a manifestation of vitamin B12 deficiency.

Tex Heart Inst J 2012 ;39(5):722-3

Department of Adult Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3461697PMC
April 2013

Biventricular intracardiac device implanted in a patient with persistent left superior vena cava.

Tex Heart Inst J 2012 ;39(4):586-7

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3423296PMC
January 2013

Marked attenuation of shock burden by the use of antitachycardia pacing therapy in a patient with an implanted cardioverter-defibrillator.

Tex Heart Inst J 2012 ;39(4):568-70

Department of Adult Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3423292PMC
January 2013

Exclusion of the left atrial appendage to prevent stroke in cases of atrial fibrillation.

Tex Heart Inst J 2012 ;39(4):535-7

Department of Internal Medicine, The University of Texas Health Science Center at Houston, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3423289PMC
January 2013

Heterogeneity of left ventricular signal characteristics in response to acute vagal stimulation during ventricular fibrillation in dogs.

Tex Heart Inst J 2011 ;38(6):621-6

Division of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3233327PMC
November 2012

Cardiac resynchronization therapy: a decade of experience and the dilemma of nonresponders.

Tex Heart Inst J 2011 ;38(4):358-60

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX 77030, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3147217PMC
January 2012

Stroke prevention in nonvalvular atrial fibrillation.

Tex Heart Inst J 2011 ;38(4):350-2

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX 77030, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3147190PMC
January 2012

Pharmacologic management of arrhythmias.

Tex Heart Inst J 2011 ;38(4):344-9

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX 77030, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3147219PMC
January 2012

Cardiac arrhythmias in women.

Tex Heart Inst J 2011 ;38(2):157-9

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066817PMC
August 2011

The evaluation and management of electrical storm.

Tex Heart Inst J 2011 ;38(2):111-21

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066819PMC
August 2011

Tachycardia-mediated cardiomyopathy and the permanent form of junctional reciprocating tachycardia.

Tex Heart Inst J 2010 ;37(6):695-8

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

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.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3014141PMC
April 2011

Race/ethnicity and the incidence of new-onset atrial fibrillation after isolated coronary artery bypass surgery.

Heart Rhythm 2010 Oct 8;7(10):1458-63. Epub 2010 Jul 8.

Department of Cardiology, Center for Cardiac Arrhythmias and Electrophysiology, The Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77030, USA.

Background: Atrial fibrillation (AF) is more prevalent in Caucasians than in persons of other racial/ethnic groups.

Objective: The purpose of this study was to examine the association between race/ethnicity and new-onset postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG).

Methods: Data from all patients with no history of AF who underwent isolated CABG at our institution from 2000 through 2008 were analyzed. Univariate analyses of preoperative and perioperative variables were performed to identify predictors of POAF. Multivariate stepwise logistic regression was performed to determine independence. Propensity-score matching was used to assess racial/ethnic differences in POAF risk.

Results: Of the 5,823 patients (mean age 72 ± 11 years; 75.5% male) included in the study, 3,966 (68%) were Caucasian (mean age 65 ± 10 years; 77.9% male). The incidence of POAF was 28.9% (1,683/5,823) overall; 32.4% (1,287/3,966) in Caucasians and 21.3% (396/1,857) in non-Caucasians. Multivariate logistic regression revealed that Caucasian race/ethnicity independently predicted POAF (odds ratio [OR] 1.8, 95% confidence interval [CI] 1.5-2.0; P <.0001). The propensity-matching analysis of 715 Caucasians and 715 non-Caucasians confirmed Caucasian race/ethnicity as an independent predictor of POAF (OR 1.7, 95% CI 1.3-2.2; P <.001). Other independent predictors were obesity (OR 1.4, 95% CI 1.0-2.0; P = .04), congestive heart failure (OR 1.8, 95% CI 1.3-2.6; P = .0002), and age 50-59 years (OR 3.7, 95% CI 1.7-8.3; P = .0006), with increasing risk for each additional increment of 10 years.

Conclusion: Caucasians are at higher risk for POAF after isolated CABG than are persons of other races. Race probably is a surrogate for unrecognized variables such as genetic disparities among racial/ethnic groups.
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http://dx.doi.org/10.1016/j.hrthm.2010.06.037DOI Listing
October 2010

Programming antitachycardia pacing for primary prevention in patients with implantable cardioverter defibrillators: results from the PROVE trial.

J Cardiovasc Electrophysiol 2010 Dec;21(12):1349-54

Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas, USA.

Objectives: the PROVE trial was designed to determine if antitachycardia pacing (ATP) is clinically beneficial for primary prevention in patients who have implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds).

Background: use of ICDs and CRT-Ds reduces mortality in patients with ventricular dysfunction and mild to moderate heart failure. However, in studies of the primary prevention population, shock-only ICDs are predominantly used, without ATP programming for less painful termination of ventricular tachycardia (VT).

Methods: we conducted a prospective, nonrandomized, multicenter study using market-released ICDs and CRT-Ds. Patients received devices programmed to deliver ATP for VT cycle lengths of 270-330 ms. Follow-up evaluation was performed at 3, 6, and 12 months. The incidence of VT and the rate of successful termination by ATP were analyzed.

Results: of 830 patients in the study population (men, 73%; mean age, 67.3 ± 12 years), 32% received single-chamber ICDs, 44% dual-chamber ICDs, and 24% CRT-Ds. ATP was attempted for 112 VT episodes in 71 patients, and 103 (92%) of the VT episodes were successfully terminated. Three VT episodes were accelerated by ATP and required termination by ICD shock; 6 episodes terminated spontaneously or by ICD shock.

Conclusions: VT is common in patients without a history of this arrhythmia who have received ICDs or CRT-Ds for primary prevention indications. Programming ICDs for ATP therapy at the time of implantation could potentially terminate most VT episodes and reduce the number of painful shocks for these patients.
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http://dx.doi.org/10.1111/j.1540-8167.2010.01825.xDOI Listing
December 2010

Lobectomy for pulmonary vein occlusion secondary to radiofrequency ablation.

J Cardiovasc Electrophysiol 2010 Sep;21(9):1055-8

Texas Heart Institute, St. Luke's Episcopal Hospital, Houston, Texas, USA.

Pulmonary vein stenosis, a recognized complication of transcatheter radiofrequency ablation in the left atrium, is often asymptomatic. Significant stenosis is commonly treated with percutaneous balloon dilation with or without stenting. We encountered a case of complete pulmonary vein occlusion that caused lobar thrombosis, pleuritic pain, and persistent cough. Imaging studies revealed virtually no perfusion to the affected lobe. A lobectomy was performed, resolving the persistent cough and pain. Pulmonary vein occlusion should be suspected in patients who present with pulmonary symptoms after having undergone ablative procedures for atrial fibrillation. This condition may necessitate surgical intervention if interventions such as balloon dilation or stenting are not possible or are ineffective. 
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http://dx.doi.org/10.1111/j.1540-8167.2010.01763.xDOI Listing
September 2010

Variability in postpacing intervals predicts global ventricular activation pattern during tachycardia.

Pacing Clin Electrophysiol 2010 Feb 18;33(2):129-34. Epub 2009 Nov 18.

Texas Heart Institute, St. Luke's Episcopal Hospital, Houston, TX 77060, USA.

Introduction: Assessment of ventricular activation pattern is critical to the successful ablation of ventricular tachycardia (VT). We have previously shown that the global atrial activation pattern during tachycardia can be rapidly and accurately assessed by calculating the postpacing interval variability (PPIV); PPIV was minimal in circuitous tachycardias and highly variable in centrifugal tachycardias. In the present study, we use the PPIV to determine the ventricular global activation pattern during VT.

Methods: Patients with mappable VT were included. We defined global ventricular activation as either centrifugal (arising from a focus with radial expansion) or circuitous (gross macro-reentrant circuit), based on the findings of electroanatomic mapping. PPIV was calculated as the difference in postpacing interval with right ventricular apical overdrive pacing during tachycardia at cycle lengths (CL) 10 ms and 30-ms shorter than tachycardia, regardless of the origin of the tachycardia. We studied 20 patients with 23 VTs (11 centrifugal, mean CL 390 +/- 36.1 ms; 12 circuitous, mean CL 418 +/- 75.7 ms).

Results: The mean PPIV was 45 +/- 16 ms for patients with centrifugal VT and 6.7 +/- 4.1 ms for patients with circuitous VT. Rank sum analysis of PPIV showed a significant difference between the two groups (P < 0.05).

Conclusions: Our data suggest that the global ventricular activation pattern during VT can be rapidly and accurately defined by assessing the PPIV. This technique allows for a rapid confirmation of the tachycardia activation and significantly facilitates mapping and ablation.
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http://dx.doi.org/10.1111/j.1540-8159.2009.02617.xDOI Listing
February 2010

Migraine and vasodepressor syncope in a large family.

Tex Heart Inst J 2009 ;36(5):468-9

Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, and University of Texas Medical School at Houston, Houston, Texas 77030, USA.

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.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763453PMC
February 2010

Cardiac resynchronization therapy in patients with right ventricular pacing-induced cardiomyopathy.

Pacing Clin Electrophysiol 2010 Jan 10;33(1):37-40. Epub 2009 Oct 10.

Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas, USA.

Background: It is not known whether patients with normal baseline left ventricular (LV) function who develop right ventricular (RV) pacing-induced cardiomyopathy as a result of dual-chamber pacing can benefit from cardiac resynchronization therapy (CRT). We retrospectively assessed the effect of a CRT upgrade on RV pacing-induced cardiomyopathy.

Methods And Results: We reviewed the charts of patients who received a CRT device for RV pacing-induced cardiomyopathy. We assessed the effects of CRT on LV function, recovery, and other response parameters. From September 2005 through February 2009, 21 patients (13 men; aged 63 + or - 9 years) underwent a treatment upgrade to a CRT system. Before the dual-chamber pacemaker was implanted, the LV ejection fraction (LVEF) was 53 + or - 2.3%. After pacing, the LVEF was 31.2 + or - 3.8%, the LV end-diastolic dimension (LVEDD) was 5.8 + or - 0.5 cm, and B-type natriuretic peptide (BNP) levels were 426 + or - 149 pg/mL. The duration of pacing before documentation of pacing-induced cardiomyopathy was 3.8 + or - 1.5 months. All the patients had been on a stable medical regimen for at least 2 months. After the upgrade to CRT, the follow-up time was 4.9 + or - 0.9 months. Sixteen patients (76%) reported a significant improvement in their symptoms. After the CRT upgrade, the LVEF increased to 37.4 + or - 9.0% (P < 0.01 vs pre-CRT). The LVEDD decreased to 5.0 + or - 1.0 cm (P = 0.03 vs pre-CRT), and BNP levels decreased to 139 + or - 92 pg/mL (P = 0.08 vs pre-CRT).

Conclusion: A CRT upgrade is an effective treatment for RV pacing-induced cardiomyopathy and should be implemented as soon as the diagnosis is established. Unfortunately, about 24% of our patients did not respond to the upgrade.
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http://dx.doi.org/10.1111/j.1540-8159.2009.02594.xDOI Listing
January 2010

Arrhythmogenicity of weight-loss supplements marketed on the Internet.

Heart Rhythm 2009 May 14;6(5):658-62. Epub 2009 Feb 14.

Center for Cardiac Arrhythmias and Electrophysiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas, USA.

Background: We examined nonprescription weight-loss supplements marketed on the Internet for ingredients with potential arrhythmogenic and life-threatening cardiac adverse effects.

Objective: We aimed to define the risks of life-threatening cardiac adverse effects that are associated with weight-loss supplements marketed on the Internet.

Methods: We entered the key words "weight-loss supplements" and "diet pills" into three popular Internet search engines. The top four nonoverlapping hits from each search engine were purchased. After receipt, the products and their ingredient lists were inspected, and Medline and the Natural Medicines Comprehensive Database were searched for reports of significant associations between each ingredient and various key words for life-threatening cardiac adverse effects.

Results: All supplements had the list of ingredients on the label. We identified 60 different ingredients (7.25 +/- 4.66 per supplement; range 1-21). Eleven ingredients representing eight different substances (because multiple names were used for some substances) were each associated with two or more reports of life-threatening cardiac complications or death. Eight of the 12 products contained one or more such ingredients, but none of these eight products had warnings about life-threatening cardiac adverse effects on the Web pages, on the labels, or in the package inserts. One product contained ma huang (Chinese ephedra), even though the marketing of ephedra-containing products is banned in the United States.

Conclusions: The Internet provides easy access to weight-loss supplements, several of which contain ingredients with potentially life-threatening adverse effects. There is a need for increased public education and awareness regarding such weight-loss products.
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http://dx.doi.org/10.1016/j.hrthm.2009.02.021DOI Listing
May 2009