INTERNAL MEDICINE Volume 67, Issue 06 | February 14, 2020

Cardiology Updates

Management of Atrial Fibrillation rhythm yield equivalent rates of mortality; however, patients
treated with catheter ablation reported markedly improved
Karl M. Richardson, MD, Assistant Professor of Cardiology, quality of life (fewer episodes of AF and improved patient–
Associate Program Director, Internal Medicine Residency reported outcomes); in patients with systolic heart failure (doc-
Program, Wake Forest School of Medicine, Winston- umented by low ejection fraction), catheter ablation markedly
Salem, NC decreased rate of mortality; CASTLE-AF trial (2018) — found
Case study 1: 62-yr-old woman with history of hypertension and that in patients with AF and heart failure, catheter ablation
obesity presents with 3-mo history of intermittent palpitations associated with decreased rates of death and hospitalization;
and shortness of breath; auscultation detects irregular rhythm; modification of risk factors — study of patients treated by abla-
electrocardiography (ECG) confirms atrial fibrillation (AF) tion found that weight loss of 13 kg, control of hypertension,
Atrial fibrillation: normal cardiac electrical activity involves regulation of diabetes mellitus (DM), and treatment of sleep
conduction from sinoatrial node to atrioventricular node and apnea led to ≈2-fold greater control of rhythm compared with
His Purkinje system and results in contraction of left ventricle; ablation alone; study found that control of sleep apnea alone
atria contract by activation of sinoatrial node (facilitate filling resulted in benefit equivalent to that from ablation
of ventricles); AF defined as uncoordinated micro-reentrant Atrial flutter: risk for stroke and outcomes of treatment (whether
electrical activity; typically originates in pulmonary veins; by rate or rhythm control) similar to those in AF; atrial flut-
causes chaotic contraction of left atrium; atrium beats errati- ter defined as macro-reentrant circuit in right atrium; locus in
cally and with varying morphology at rate of ≈400 beats/min; cavotricuspid isthmus; single ablation achieves rates of cure
ventricle responds irregularly at rate of 100 to 120 beats/min; of 95% to 98%; if cure confirmed by follow-up monitoring,
causes — sleep apnea, hypertension, obesity, and excessive anticoagulation can be safely stopped
alcohol intake most common; elevated left atrial pressure from Case study 2: 67-yr-old asymptomatic man underwent Holter
any cause (eg, hypertension, sleep apnea, obesity, heart failure, monitoring for incidentally discovered premature ventricular
mitral valve disease) predisposes to AF; treatment of causative contractions; 3 episodes of AF found, each lasting few hours;
factors critical; other causes include pneumonia, surgery, and treatment of rate or rhythm unnecessary in asymptomatic
genetic predisposition patient; however, patient is at risk for stroke
Workup: laboratory tests include complete blood count, screen- Prevention of stroke: incidence of stroke in patients with
ing for infection and inflammation, brain natriuretic peptide, paroxysmal or infrequent AF is equivalent to (or possibly
renal function (implications for anticoagulation), electrolytes higher than) incidence in patients with chronic AF; contrary
(disorders can precipitate AF), and thyroid function tests; to common misunderstanding, control of rhythm by ablation
echocardiography recommended in patients with new-onset or drug (eg, amiodarone, sotalol) does not eliminate risk for
AF to evaluate mitral valve, ejection fraction, and wall motion; stroke; ablation rarely achieves 100% cure (rate of recurrence
AF not characteristic of ischemia; stress test not indicated after successful ablation ≈20%); untreated AF is most common
(abnormalities often incidental, and interventions for ischemia cause of stroke in United States; risk for stroke 5-fold higher
unlikely to be beneficial) than for individuals without AF; CHADS2-VASc (conges-
Principles of management: 2 independent issues require con- tive heart failure, hypertension, age, DM, previous stroke/
sideration, ie, control of rate or rhythm and anticoagulation; transient ischemic attack — vascular disease) calculates
rate controlled by β-blockers or calcium-channel blockers; annual risk for stroke; new guidelines from American Col-
rhythm controlled by cardioversion, antiarrhythmic agent, or lege of Cardiology recommend anticoagulation in men with
ablation; reduction of risk for stroke achieved by anticoagula- AF and CHADS2-VASc score ≥2 and women with AF and
tion or occlusion of left atrial appendage (LAA); rate vs rhythm score ≥3
control — presence of symptoms determines choice between Case study 2 (continued): comorbid conditions include DM and
rate and rhythm; AFFIRM trial (2002) — randomized con- hypertension, so CHADS2-VASc score 3; annual risk for stroke
trolled trial found that treatment of rate or rhythm resulted in 3.2%; anticoagulation indicated
equivalent overall outcomes; failure to standardize anticoagu- Efficacy of anticoagulation: meta-analysis found that warfarin
lation in patients treated by rhythm control was shortcoming of reduces risk for stroke 65% to 70% compared with placebo
trial; CABANA trial (2019) — confirmed that control of rate or (absolute risk for stroke ≈1%/yr); warfarin decreases risk 40%

Educational Objectives Faculty Disclosure

The goal of this program is to improve the management of In adherence to ACCME Standards for Commercial Support,
atrial fibrillation and outpatient monitoring of cardiac condi- Audio Digest requires all faculty and members of the planning
tions. After hearing and assimilating this program, the clinician committee to disclose relevant financial relationships within
will be better able to: the past 12 months that might create any personal conflicts of
1. Plan a workup for a patient with new onset of atrial interest. Any identified conflicts were resolved to ensure that
fibrillation. this educational activity promotes quality in health care and
not a proprietary business or commercial interest. For this
2. Select patients with atrial fibrillation who may benefit
program, members of the faculty and the planning commit-
from control of rhythm.
tees reported nothing to disclose. In his lecture, Dr. Widmer
3. Define the indications for anticoagulation in patients with presents information that is related to the off-label or investiga-
atrial fibrillation. tional use of a therapy, product, or device.
4. Choose appropriate anticoagulation agents for patients
with atrial fibrillation.
5. Evaluate the increasing role of mobile devices in the care
of patients with cardiac disease.

IM-67-06
 Audio Digest Internal Medicine 67:06
to 50% compared with aspirin; yearly incidence of major bleed- Trial of rhythm control: initiate treatment with amiodarone
ing from anticoagulation 1 in 1000 patients (compared with and cardioversion; if symptoms improved, ablation reason-
prevention of 31 strokes or systemic emboli); patients with able option; if symptoms not improved, rate control preferred
higher CHADS2-VASc less commonly treated (likely related option; in young patients, reasonable to refer directly to abla-
to greater frailty); in many patients, risk for bleeding is much tion; if symptoms not clearly associated with AF, initial trial of
lower than risk for stroke amiodarone and cardioversion preferred
Case study 3: 78-yr-old woman presents with remote history of Management of transient AF: evidence lacking; guidelines do
coronary artery disease, hypertension, and asymptomatic AF; not distinguish between acute and chronic AF; in patients pre-
currently in normal sinus rhythm; ECG from 6 mo ago shows senting with brief AF following cardiac surgery (or other acute
AF; CHADS2-VASc score 5; risk for stroke 6.7%/yr event), calculate CHADS2VASc; if high, and risk for bleeding
Choice of anticoagulation: data indicate that novel oral antico- low, anticoagulation recommended; in patients with lower
agulants (NOACs; eg, apixaban [Eliquis], rivaroxaban, dabiga- CHADS2VASc (eg, ≤3), initial anticoagulation and 14-day
tran, edoxaban) superior to warfarin (eg, Coumadin, Jantoven); monitor at 3 to 6 mo recommended; in absence of AF, antico-
NOACs associated with relative risk for stroke or systemic agulation may be stopped; repeat monitoring advisable
embolization 0.82; risk for bleeding and intracranial bleed- Suggested Readings
ing significantly lower; ARISTOTLE trial (2011) found that
Coppens M et al: Efficacy and safety of apixaban compared with aspi-
apixaban associated with lower rates of stroke, systemic embo- rin in patients who previously tried but failed treatment with vitamin K
lization, and major bleeding compared with warfarin; current antagonists: results from the AVERROES trial. Eur Heart J 2014 Jul
guidelines recommend NOACS rather than warfarin; NOACs 21;35(28):1856-63; Granger CB et al: Apixaban versus warfarin in
should not be used in patients with moderate or severe mitral patients with atrial fibrillation. N Engl J Med 2011 Sep 15;365(11):981-92;
stenosis or mechanical mitral valve January CT et al: 2019 AHA/ACC/HRS focused update of the 2014
Case study 4: 83-yr-old woman with frailty, history of DM, AHA/ACC/HRS Guideline for the Management of Patients with Atrial
and recent fall; lives independently; AF diagnosed recently; Fibrillation: a report of the American College of Cardiology/American
because of risk for falls, aspirin might seem tempting option Heart Association Task Force on Clinical Practice Guidelines and the
(to reduce risk for bleeding compared to NOAC or warfarin); Heart Rhythm Society in Collaboration with the Society of Thoracic
Surgeons. Circulation 2019 Jul 9;140(2):e125-e151; Linz D et al: Asso-
however, randomized controlled trial found no advantage of ciations of obstructive sleep apnea with atrial fibrillation and continu-
aspirin over placebo, and aspirin increases risk for bleeding; ous positive airway pressure treatment: a review. JAMA Cardiol 2018
aspirin not recommended in AF; study of patients with AF Jun 1;3(6):532-540; Marrouche NF and Brachmann J: Catheter
found annual risk for stroke in patients taking aspirin 3.7%, ablation for atrial fibrillation with heart failure. N Engl J Med 2018
compared with 1.6% for those taking apixaban; apixaban asso- Feb 1;378(5):417-427; Packer DL et al: Effect of catheter ablation vs
ciated with slightly higher overall incidence of bleeding but antiarrhythmic drug therapy on mortality, stroke, bleeding, and cardiac
equivalent rate of intracranial bleeding arrest among patients with atrial fibrillation: the CABANA random-
Case study 5: patient presents with AF and recent major gas- ized clinical trial. JAMA 2019 Apr 2;321(13):1261-1274; Piccini JP
trointestinal bleeding; calculated annual risk for stroke ≈10%; and Fauchier L: Rhythm control in atrial fibrillation. Lancet 2016 Aug
20;388(10046):829-40; Wyse DG et al: A comparison of rate control
annual risk for bleeding ≈6% (calculated by HAS-BLED score) and rhythm control in patients with atrial fibrillation. N Engl J Med 2002
Occlusion of LAA: LAA area of poor blood flow in AF; source Dec 5;347(23):1825-33.
of clots in ≈90% of patients with AF who have clots; devices
available include Watchman and Amulet; study with 5-yr Wearable Devices and New Patient Technology in
follow-up found warfarin and occlusion associated with sta- Cardiovascular Care
tistically similar rates of ischemic stroke (trend to higher rate
of stroke in occlusion cohort); occlusion associated with much Robert Jay Widmer, MD, Interventional Cardiologist, Baylor
lower rate of hemorrhagic stroke; reasonable alternative in Scott and White Health, Temple, TX
patients unable to tolerate anticoagulation, although less effica- Digital health: umbrella term that includes genomics, precision
cious than anticoagulation medicine, mobile technology, wearable devices, and mobile
Questions and Answers health; American College of Cardiology emphasizes that
Efficacy of clopidogrel (Plavix) for prevention of stroke in patients and providers should be at center of technology revolu-
patients with AF: no data comparing clopidogrel with aspirin tion; average cell phones per person 1.6 worldwide; cardiovas-
in patients receiving apixaban; trials comparing clopidogrel with cular technology — portable cardiac monitors (eg, Zio patch);
aspirin in patients with coronary artery disease treated by apixa- detection of pulse and pulse variability using light technology
ban have found equivalent efficacy; in patients with stroke, add- (eg, with Apple Watch); portable electrocardiography (ECG;
ing clopidogrel to aspirin improves outcomes; patients presenting Cardia monitor provides lead I reading); other cardiac monitors
to clinic taking clopidogrel and aspirin for stroke should undergo detect pulse rate using optical sensors; studies — 1500 studies
14-day cardiac monitoring (eg, Zio patch) to look for AF registered on clinicaltrials.gov (many more not registered);
Implantable loop recorder: may be used in patients with stroke cardiovascular disease accounts for 20%; other studies focusing
to screen for AF; rate of AF in patients with cryptogenic stroke on mental health and maternal and reproductive health
30% to 40% Clinical efficacy of mobile health: randomized controlled trial
Occlusion of LAA: protocol calls for anticoagulation for 6 wk, found that patients given MyFitnessPal smartphone app failed
followed by aspirin and clopidogrel for 6 mo; after 6 mo either to lose weight after 6 mo; randomized controlled trial of young
aspirin continued alone or all therapy stopped patients genetically predisposed to cardiovascular disease found
Rate or rhythm control: outcomes similar except in patients standard intervention associated with greater weight loss than
with low ejection fraction; rhythm control improves quality of enhanced intervention (including use of pedometer [Fitbit]);
life in patients with symptoms (eg, palpitations, exertional dys- study of patients with heart failure found rate of 30-day read-
pnea, fatigue); attempt at rhythm control reasonable in patients mission ≈50% despite use of wearable technology; in meta-
with symptoms; if symptoms not improved, control of comor- analysis of primary prevention of heart disease, digital health
bid conditions recommended failed to improve outcomes significantly; studies of secondary
Dose of apixaban: appropriate dose 5 mg twice daily; apixaban prevention found that appropriate use of device for appropriate
associated with lowest risk for bleeding and stroke; 2.5 mg duration prevents rehospitalization
twice daily indicated in elderly or low-weight patients (<60 kg) mSToPS trial: studied ability of Zio patch to detect atrial fibril-
with renal failure, and elderly patients with low weight lation (AF) in patients with CHADS2VASc score >2; ≈1700
 Audio Digest Internal Medicine 67:06
actively monitored participants completed study (they were monitor well validated; Garmin monitor tracks activity and inter-
compared to observational control cohort); Zio patch identi- acts with cell phone and iPad; Spire Health device — gauges
fied more individuals with AF; at 12 mo, 190 new cases of breathing; reminds patients to take deep breaths; potentially
AF found in total, 109 of which were in actively monitored useful for patients with atrial fibrillation and hypertension;
groups; in 44 of 109 actively monitored patients, however, AF Cardia device — well tested and validated; approved by Food
was identified before or after monitoring but not detected dur- and Drug Administration; cost $75; provides lead I of ECG;
ing monitoring; actively monitored patients underwent more reproducible; 3-lead system is in development; 12-lead device
procedures (eg, pacemakers, defibrillators, ablations) but without detecting ST and rhythm changes in field is also in development;
greater utilization of other aspects of health care (eg, emergency low price is advantage over Holter monitor or Zio patch
department, clinic visits) Conclusions: clinical use should focus on selecting appropri-
Apple Health app: includes monitoring of nutrition, food intake, ate device and timing for each patient; efficacy for modify-
activity, mindfulness, and sleep; type of sleep or movement ing behavior largely unproven (eg, weight loss, treatment
during sleep not tracked; benefits of wearable sleep monitoring adherence)
devices unproven; functions relating to mindfulness, reproduc- Question and Answer
tive health, fertility, and maternal-fetal health introduced in
2019; allows consolidation of medical reports (eg, uploading Use of Cardia: requires subscription; detects supraventricu-
echocardiography reports); Apple Watch ECG — uses optical lar tachycardia (eg, useful in patients with anxiety-induced
sensor to detect pulse waveform; limited to detecting regular- tachycardia)
ity or irregularity; ECG not obtainable Suggested Readings
Apple Heart Study: evaluated ability to detect and monitor AF; Hannan AL: Impact of wearable physical activity monitoring devices
captured data on ≈420,000 individuals; only 0.5% of popula- with exercise prescription or advice in the maintenance phase of cardiac
tion received notification on watch; incidence of obesity 38% rehabilitation: systematic review and meta-analysis. BMC Sports Sci Med
and hypertension 20% (ie, population at moderate risk for AF); Rehabil 2019; 11: 14; Laing BY et al: Effectiveness of a smartphone
median age 41; ECG patch applied to 450 patients; of those application for weight loss compared with usual care in overweight pri-
monitored, AF found in 34%; conclusions — yield of detection mary care patients: a randomized, controlled trial. Ann Intern Med 2014
low; value of screening large population questionable; may be Nov 18;161(10 Suppl):S5-12; Steinhubl SR et al: Effect of a home-
useful in patients with recurrent symptoms (eg, syncope, palpi- based wearable continuous ECG monitoring patch on detection of undi-
agnosed atrial fibrillation: The mSToPS randomized clinical trial. JAMA
tations) or high CHADS2VASc score 2018 Jul 10;320(2):146-155; Turakhia MP et al: Rationale and design
More devices for mobile health: Fitbit — easy to use and of a large-scale, app-based study to identify cardiac arrhythmias using a
wear; models vary from sophisticated smart watches with smartwatch: The Apple Heart Study. Am Heart J 2019 Jan;207:66-75;
interconnectivity to devices that simply monitor heart rate; Widmer RJ1 et al: Digital health interventions for the prevention of
Abbott — developing implantable pulmonary artery pressure cardiovascular disease: a systematic review and meta-analysis. Mayo Clin
sensor; other devices — Withings Bluetooth blood pressure Proc 2015 Apr;90(4):469-80.

Acknowledgments
Dr. Richardson was recorded at the 48th Annual Emery C. Miller Medical Symposium, presented by Wake Forest School of Medicine,
Northwest Area Health Education Center and held July 29 to August 2, 2019, in Myrtle Beach, SC. For information on upcoming
CME conferences presented by Wake Forest, please visit northwestahec.wakehealth.edu. Dr. Widmer was recorded at the 38th Annual
Internal Medicine Review for the Primary Care Provider, presented by Baylor Scott and White Health, A. Webb Roberts Center for
Continuing Medical Education, and held July 15-19, 2019, in San Padre, TX. For information on upcoming CME conferences presented
by Baylor Scott and White Health, A. Webb Roberts Center for Continuing Medical Education, please visit https://www.bswhealth.med/
cme/. The Audio Digest Foundation thanks the speakers and sponsors for their cooperation in the production of this program.

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 Audio Digest Internal Medicine 67:06
Cardiology Updates
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1. Which of the following conditions is one of the 4 major causes of atrial fibrillation?
(A) Coronary artery disease (C) Pulmonary hypertension
(B) Aortic valve disease (D) Sleep apnea *****

2. Relevant laboratory testing in patients with newly diagnosed atrial fibrillation includes all of the following tests, EXCEPT:
(A) Complete blood count (C) Troponin *****
(B) Brain natriuretic hormone (D) Renal function tests

3. Which of the following tests is recommended in the evaluation of a patient with new atrial fibrillation?
(A) Stress test (C) Echocardiography *****
(B) Nuclear scan (D) 24-hr Holter monitor

4. A study of patients with atrial fibrillation found that control of which of the following comorbidities alone achieved out-
comes equivalent to ablation therapy?
(A) Hypertension (C) Ischemic heart disease
(B) Heart failure (D) Sleep apnea *****

5. According to the American College of Cardiology guidelines, anticoagulation is recommended in men with atrial fibrilla-
tion and a CHADS2-VASc score of _______, and in women with atrial fibrillation and a score of _______.
(A) ≥1; ≥1 (C) ≥2; ≥2
(B) ≥1; ≥2 (D) ≥2; ≥3 *****

6. Based on current guidelines, which of the following anticoagulant agents is recommended in patients with atrial fibrillation?
(A) Warfarin (C) Aspirin plus clopidogrel
(B) Apixaban ***** (D) A or B

7. Which of the following approaches is recommended in the initial treatment of a 65-yr-old patient with symptomatic atrial
fibrillation?
(A) β-blocker (C) Amiodarone and cardioversion *****
(B) Amiodarone (D) Ablation

8. Which of the following statements about the left atrial appendage (LAA) and prevention of stroke is true?
(A) The LAA is the source of the clot in ≈40% of patients with atrial fibrillation who have clots
(B) LAA occlusion and anticoagulation with warfarin result in similar rates of ischemic stroke *****
(C) LAA occlusion carries a higher risk for hemorrhagic stroke than does anticoagulation therapy
(D) LAA occlusion is more efficacious than anticoagulation therapy

9. Which of the following wearable devices provides an electrocardiography tracing?

(A) Cardia monitor ***** (C) Fitbit
(B) Apple Watch (D) Withings Bluetooth monitor

10. The use of mobile health technology has been demonstrated to be effective in which of the following situations?
(A) Promoting weight loss
(B) Improving outcomes in primary prevention of heart disease
(C) Providing a high yield for detecting atrial fibrillation in large-scale population screening
(D) Preventing rehospitalization in secondary prevention of heart disease *****

Answers to Audio Digest Internal Medicine Volume 67, Issue 04: 1-C, 2-B, 3-C, 4-C, 5-D, 6-B, 7-C, 8-D, 9-D, 10-C

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