Clinical Focus

  • Cardiovascular Disease
  • Arrhythmias
  • Cardiovascular Medicine
  • Pacemakers/Defibrillators
  • Syncope

Academic Appointments

Professional Education

  • Fellowship: Barnes-Jewish Hospital - GME (1982) MO
  • Fellowship: St Louis City Hospital/Washington University School of Med (1981) MO
  • Residency: Johns Hopkins Hospital Internal Medicine Residency (1979) MD
  • Internship: Johns Hopkins Hospital Internal Medicine Residency (1977) MD
  • Medical Education: Case Western Reserve School of Medicine (1976) OH
  • Board Certification: American Board of Internal Medicine, Cardiovascular Disease (1983)
  • Board Certification: American Board of Internal Medicine, Internal Medicine (1980)

All Publications

  • 2015 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Treatment of Postural Tachycardia Syndrome, Inappropriate Sinus Tachycardia, and Vasovagal Syncope HEART RHYTHM Sheldon, R. S., Grubb, B. P., Olshansky, B., Shen, W., Calkins, H., Brignole, M., Raj, S. R., Krahn, A. D., Morillo, C. A., Stewart, J. M., Sutton, R., Sandroni, P., Friday, K. J., Hachul, D. T., Cohen, M. I., Lau, D. H., Mayuga, K. A., Moak, J. P., Sandhu, R. K., Kanjwal, K. 2015; 12 (6): E41-E63

    View details for DOI 10.1016/j.hrthm.2015.03.029

    View details for PubMedID 25980576

  • Feasibility of Extended Ambulatory Electrocardiogram Monitoring to Identify Silent Atrial Fibrillation in High-risk Patients: The Screening Study for Undiagnosed Atrial Fibrillation (STUDY-AF) CLINICAL CARDIOLOGY Turakhia, M. P., Ullal, A. J., Hoang, D. D., Than, C. T., Miller, J. D., Friday, K. J., Perez, M. V., Freeman, J. V., Wang, P. J., Heidenreich, P. A. 2015; 38 (5): 285-292


    Identification of silent atrial fibrillation (AF) could prevent stroke and other sequelae.Screening for AF using continuous ambulatory electrocardiographic (ECG) monitoring can detect silent AF in asymptomatic in patients with known risk factors.We performed a single-center prospective screening study using a wearable patch-based device that provides up to 2 weeks of continuous ambulatory ECG monitoring (iRhythm Technologies, Inc.). Inclusion criteria were age ≥55 years and ≥2 of the following risk factors: coronary disease, heart failure, hypertension, diabetes, sleep apnea. We excluded patients with prior AF, stroke, transient ischemic attack, implantable pacemaker or defibrillator, or with palpitations or syncope in the prior year.Out of 75 subjects (all male, age 69 ± 8.0 years; ejection fraction 57% ± 8.7%), AF was detected in 4 subjects (5.3%; AF burden 28% ± 48%). Atrial tachycardia (AT) was present in 67% (≥4 beats), 44% (≥8 beats), and 6.7% (≥60 seconds) of subjects. The combined diagnostic yield of sustained AT/AF was 11%. In subjects without sustained AT/AF, 11 (16%) had ≥30 supraventricular ectopic complexes per hour.Outpatient extended ECG screening for asymptomatic AF is feasible, with AF identified in 1 in 20 subjects and sustained AT/AF identified in 1 in 9 subjects, respectively. We also found a high prevalence of asymptomatic AT and frequent supraventricular ectopic complexes, which may be relevant to development of AF or stroke. If confirmed in a larger study, primary screening for AF could have a significant impact on public health.

    View details for DOI 10.1002/clc.22387

    View details for PubMedID 25873476

  • Clinical reminders to providers of patients with reduced left ventricular ejection fraction increase defibrillator referral: a randomized trial. Circulation. Heart failure Gupta, A., Gholami, P., Turakhia, M. P., Friday, K., Heidenreich, P. A. 2014; 7 (1): 140-145


    Background- Many patients who are candidates for implantable cardioverter defibrillators (ICDs) are not referred for potential implantation. We sought to determine if a simple provider reminder would increase referrals. Methods and Results- We identified consecutive patients from January 2007 through July 2010 in the VA Palo Alto Health Care System with a left ventricular ejection fraction <35% on echocardiography. Patients were excluded using available administrative data only (no chart review) if they were known to have an ICD, if they were ≥80 years old, or if they did not have a current primary care or cardiology provider within the system. We randomized patients to no intervention or a clinical note to the provider in the medical record. The outcomes were referral for consideration of defibrillator implantation (primary) and documented discussion (secondary). Of 330 patients with left ventricular ejection fraction ≤35%, 128 were known to have an ICD, 85 were no longer followed in the healthcare system, and 28 were ≥80 years old, leaving 89 patients to be randomized. Forty-six patients were randomized to intervention and 43 to control. Eleven of 46 (24%) intervention patients were referred for consideration of ICD implantation during the following 6 months versus 1 of 43 (2%) control patients (P=0.004). Overall, 31 of 46 (67%) intervention patients versus 19 of 43 (44%) control patients had documentation discussing potential candidacy for defibrillators (P=0.05). Conclusions- In patients with low left ventricular ejection fraction, a simple electronic medical record-based intervention directed to their providers improved the rates of referral for ICD implantation. Clinical Trial Registration- URL: Unique identifier: NCT01217827.

    View details for DOI 10.1161/CIRCHEARTFAILURE.113.000753

    View details for PubMedID 24319096

  • Manometric abnormalities in the postural orthostatic tachycardia syndrome: a case series. Digestive diseases and sciences Huang, R. J., Chun, C. L., Friday, K., Triadafilopoulos, G. 2013; 58 (11): 3207-3211


    Postural orthostatic tachycardia syndrome (POTS) is a rare disease that is believed to be mediated by dysautonomia. Gastrointestinal complaints in POTS patients are common and disturbing but not well characterized.We hypothesized that gastrointestinal dysmotility may be contributory to these symptoms.We studied 12 POTS patients who presented with gastrointestinal symptoms to a tertiary referral center. Gastrointestinal symptoms were quantified using a previously validated symptom questionnaire. All patients underwent gastroduodenal manometry (GDM); select patients also underwent further testing including esophageal manometry (EM), anorectal manometry (ARM), plain abdominal radiography (AXR), abdominal computed tomography (CT), gastric emptying studies (GES), and colonic transit time (CTT) studies.The four most common symptoms were bloating, constipation, abdominal pain, and nausea/vomiting, all experienced by greater than 70 % of patients. On GDM testing, 93 % of patients demonstrated signs of neuropathy, and the most common abnormalities observed included bursts of uncoordinated phasic activity in both fasting (59 %) and post-prandial (42 %) states, low contractility in the post-prandial state (67 %), and lack of post-prandial pattern (42 %). A total of 67 % of patients undergoing EM and 86 % of those undergoing ARM demonstrated abnormalities consistent with dysmotility. On AXR or CT, 58 % demonstrated either dilated intestinal loops or air-fluid levels. On CTT 80 % demonstrated delayed colonic transit, while on GES 60 % demonstrated delayed gastric emptying.In this cohort of POTS patients with gastrointestinal symptoms, there is a high prevalence of abnormal manometric and radiographic findings suggestive of dysmotility.

    View details for DOI 10.1007/s10620-013-2865-9

    View details for PubMedID 24068608

  • Semantic Confusion: The Case of Early Repolarization and the J Point AMERICAN JOURNAL OF MEDICINE Perez, M. V., Friday, K., Froelicher, V. 2012; 125 (9): 843-844

    View details for DOI 10.1016/j.amjmed.2011.08.024

    View details for PubMedID 22340816

  • Abrupt bradycardia and grouped beating during treadmill testing: A mimic of upper rate behavior HEART RHYTHM Woods, C. E., Friday, K., Wang, P., Turakhia, M. P. 2012; 9 (7): 1165-1167

    View details for DOI 10.1016/j.hrthm.2011.12.020

    View details for PubMedID 22209946

  • Potential relationship between gastroesophageal reflux disease and atrial arrhythmias JOURNAL OF CLINICAL GASTROENTEROLOGY Gerson, L., Friday, K., Triadafilopoulos, G. 2006; 40 (9): 828-832


    A potential reduction in symptoms related to atrial fibrillation after treatment of gastroesophageal reflux disease symptoms with proton pump inhibitor therapy has been previously described. However, illustration of this relationship by combined 24-hour pH and ambulatory Holter monitoring has not been performed. We report 3 patients with symptoms of both palpitations and reflux who underwent simultaneous Holter and 24-hour ambulatory pH monitoring off of antireflux therapy. All of the patients reported a reduction in arrhythmia symptoms on proton pump inhibitor therapy. The findings from this preliminary series suggest a potential relationship between gastroesophageal reflux disease and atrial arrhythmias that might improve with antireflux therapy. Patients with documentation of both atrial arrhythmias and reflux should have a trial of aggressive acid suppressive therapy To further confirm this relationship, larger prospective studies are needed to assess whether maximal acid suppression improves arrhythmias.

    View details for PubMedID 17016140

  • Significance of inducible ventricular flutter/fibrillation in risk stratification in patients with coronary artery disease INTERNATIONAL JOURNAL OF CARDIOLOGY Matsushita, T., Chun, S., Liem, L. B., Friday, K. J., Sung, R. J. 2004; 94 (1): 67-71


    Although inducible ventricular fibrillation (VF) has been used as an indication for prophylactic implantation of cardioverter-defibrillators (ICDs) in patients with coronary artery disease (CAD), the significance of inducible VF remains controversial.Among 364 CAD patients who underwent electrophysiologic (EP) study for risk stratification, 23 patients, 12 without any history of VF or cardiac arrest (group A) and 11 with previously documented VF or cardiac arrest (group B), exhibited inducible ventricular flutter (VFL) or VF and subsequently underwent ICD implantation. Additionally, 11 CAD patients without previous VF or cardiac arrest, who had no inducible ventricular tachyarrhythmias but received an ICD, were included for comparison (group C).During 2 years of follow-up, 1 (8%), 5 (45%), and 1 (9%) patients had appropriate ICD shocks in groups A, B, and C, respectively. The survival free from appropriate ICD shocks was significantly lower in group B compared to groups A and C (p<0.05). There were no significant differences in age, sex, ejection fraction (EF), or induction protocol between groups A and B or between groups A and C.In CAD patients with inducible VFL/VF, patients without any history of VF or cardiac arrest had significantly lower incidence of appropriate ICD shocks when compared to those with such clinical events. Conversely, in CAD patients without any history of VF or cardiac arrest, incidence of appropriate ICD shocks was similar regardless of inducible VFL/VF. Inducible VFL/VF is therefore not useful as an indication for prophylactic ICD implantation in this patient population.

    View details for DOI 10.1016/j.ijcard.2003.04.008

    View details for PubMedID 14996477

  • Limited predictive value of inducible sustained ventricular tachycardia for future occurrence of spontaneous ventricular tachycardia in patients with coronary artery disease and relatively preserved cardiac function JOURNAL OF ELECTROCARDIOLOGY Matsushita, T., Chun, S., Liem, L. B., Friday, K. J., Sung, R. J. 2003; 36 (3): 205-211


    To evaluate the significance of inducible sustained ventricular tachycardia (VT) in patients with coronary artery disease and relatively preserved cardiac function, 33 patients who met the following criteria were studied; documented nonsustained VT but no history of life-threatening arrhythmia, inducible sustained VT at electrophysiologic study, and implantation of a cardioverter-defibrillator. Eighteen patients developed clinical sustained VT within 2 years. By univariate analysis, left ventricular ejection fraction (EF) and the cycle length of induced VT were associated with clinical VT occurrence. By multivariate analysis, however, EF was the only independent predictor. Among 23 patients with EF 40% (P <.01). In coronary artery disease patients with relatively preserved EF, the incidence of clinical VT is considerably low even though sustained VT is inducible. Inducible VT is therefore not appropriate for risk stratification in this patient population.

    View details for DOI 10.1016/S0022-0736(03)00032-3

    View details for PubMedID 12942482

  • Unidirectional conduction block at cavotricuspid isthmus created by radiofrequency catheter ablation in patients with typical atrial flutter JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY Matsushita, T., Chun, S., Liem, L. B., Friday, K. J., Sung, R. J. 2002; 13 (11): 1098-1102


    Although unidirectional conduction block at the cavotricuspid isthmus can be created by radiofrequency ablation for atrial flutter, its underlying mechanism has not been elucidated.Twenty-seven patients (22 men and 5 women; mean age 59 +/- 11 years) who met the following criteria were studied: (1) bidirectional isthmus conduction demonstrable at baseline; (2) at least one linear lesion attempted on the cavotricuspid isthmus with radiofrequency catheter ablation; and (3) conduction times at anterolateral and posteromedial portions of the isthmus measured for both clockwise and counterclockwise directions before the ablation procedure. Unidirectional conduction block was observed before achieving bidirectional block in 9 patients (group I); the remaining 18 patients did not exhibit unidirectional conduction block (group II). All unidirectional conduction blocks were demonstrated in the counterclockwise direction. Anterolateral isthmus conduction time in group I was significantly longer than that in group II in both directions. However, there were no significant differences in posteromedial isthmus conduction time between groups I and II in either direction. Anterolateral isthmus conduction time was significantly longer than posteromedial conduction time in group I but not in group II.There were significant differences in conduction properties at the cavotricuspid isthmus between patients who developed unidirectional conduction block and those who did not. Our results support the notion that anisotropy contributes to the genesis of unidirectional conduction block at the cavotricuspid isthmus during the radiofrequency ablation procedure.

    View details for PubMedID 12475099