Patrick Antoun

Indiana University-Purdue University School of Medicine, Indianapolis, Indiana, United States

Are you Patrick Antoun?

Claim your profile

Publications (5)14.28 Total impact

  • Patrick Antoun · Jeffrey A Breall ·

    The Journal of invasive cardiology 01/2014; 26(1):16-17. · 0.95 Impact Factor
  • Patrick Antoun · Hicham El Masry · Jeffrey A Breall ·

    Catheterization and Cardiovascular Interventions 09/2009; 74(3). DOI:10.1002/ccd.22045 · 2.11 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The mechanism of sinoatrial node (SAN) dysfunction in atrial fibrillation (AF) is unclear. The purpose of this study was to test the hypothesis that defective spontaneous sarcoplasmic reticulum (SR) Ca(2+) release (Ca(2+) clock) is in part responsible for SAN dysfunction in AF. Arrhythmic events and SAN function were evaluated in pacing-induced AF dogs (n = 7) and in normal dogs (n = 19) with simultaneous intracellular calcium (Ca(i)) and membrane potential recording. AF dogs had frequent sinus pauses during Holter monitoring. Isolated right atrium (RA) from AF dogs showed slower heart rate (P = .001), longer SAN recovery time (P = .001), and longer sinoatrial conduction time (P = .003) than normal. In normal RAs, isoproterenol 0.3 and 1 mumol/L increased heart rate by 96% and 105%, respectively. In contrast, in RAs from AF dogs, isoproterenol increased heart rate by only 60% and 72%, respectively. Isoproterenol induced late diastolic Ca(i) elevation (LDCAE) at superior SAN in all 19 normal RAs but in only 3 of 7 AF RAs (P = .002). In AF RAs without LDCAE (n = 4), heart rate increased by the acceleration of ectopic foci. Caffeine (20 mmol/L) injection increased heart rate with LDCAE in all 6 normal RAs but did not result in LDCAE in any of the 5 AF RAs (P = .002). Type 2 ryanodine receptor (RyR2) in the superior SAN of AF dogs was decreased to 33% of normal (P = .02). SAN dysfunction in AF is associated with Ca(2+) clock malfunction, characterized by unresponsiveness to isoproterenol and caffeine and down-regulation of RyR2 in SAN.
    Heart rhythm: the official journal of the Heart Rhythm Society 09/2009; 7(1):88-95. DOI:10.1016/j.hrthm.2009.09.018 · 5.08 Impact Factor
  • Patrick Antoun · Hicham El Masry · Jeffrey A Breall ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Over the years, alcohol septal ablation has become an effective and well-accepted modality in the treatment of patients with hypertrophic obstructive cardiomyopathy refractory to standard medical therapy. Malignant tachyarrythmias infrequently complicates the procedure and are usually self-terminating. We describe a case of alcohol septal ablation complicated by sudden cardiac death occurring immediately following the procedure requiring prolonged resuscitative efforts with eventual complete recovery. We also discuss the pathophysiologic significance of this event in the setting of this cardiomyopathy and its relevance as a complication of the procedure.
    Catheterization and Cardiovascular Interventions 06/2009; 73(7):956-9. DOI:10.1002/ccd.21849 · 2.11 Impact Factor
  • Inder M Singh · Patrick S Antoun · Laura Baugh · Dragos Sabau · John C Bailey ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Neurocardiogenic syncope is not an uncommon occurrence in the general population and affects people across a wide range of age groups. Several sub-specialties are involved in the management of this phenomenon and quite often a multidisciplinary approach is needed for arriving at the final diagnosis and deciding on the optimal treatment for this condition. Often, a thorough history and physical examination will aid in narrowing the differential of syncope and, in the right setting, both passive and provocative testing can be complementary. Neurocardiogenic syncope with a malignant course is a serious entity and usually needs prompt identification of its underlying etiology. It has been generally attributed to a severe cardioinhibitory or vasodepressor mechanism and most cases required tailored therapy. We describe a case which has many of the elements described above - a multidisciplinary approach, malignant neurocardiogenic syncope with profound asystole from a cardioinhibitory response, simplistic bed-side provocative testing, and tailored therapy.
    International journal of cardiology 10/2007; 130(1):e47-9. DOI:10.1016/j.ijcard.2007.07.028 · 4.04 Impact Factor