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• Received his master degree in 1994 at Shanghai Second Medical University;
• Took his doctor’s degree on Endocrinology at shanghai Jiaotong University school of medicine in 2007;
• From the year 2001 to 2003, He took an advanced study in Baylor College of Medicine , America.
• Headman, Endocrinology and Metabolism section, Institute of Health Sciences, Shanghai Institutes for Biological Sciences since 2004.
• Chief of office, Thyroid disease education project team, Ministry of Health, China since 2009;
• Youth member, Endocrinology society of Chinese Medical Association in 2009.
• Committee member of Chinese thyroid Association in 2010.
Shu Wang, MD, PhDThe archiater of Department of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, China. Doctoral supervisor.
The Cardiovascular System in Thyrotoxicosis
Dept. of Endocrinology and Metabolism, Ruijin Hospital, Shanghai Jiaotong University, School of Medicine
Shanghai, China
Dr. Shu Wang [email protected]
• Thyrotoxicosis has important clinical
consequences for the cardiovascular systems.
• Thyrotoxicosis can increase cardiovascular
morbidity and mortality.
• The cause of cardiovascular signs and symptoms by thyrotoxicosis can easily be neglected.
keep “Thyrotoxicosis” in mind!
• Thyrotoxicosis is the clinical syndrome of hyperthyroidism resulting from excessive quantities of the thyroid hormones.
Case 1 A 63-year-old female patient Chest distress ,palpitation behind fatigue, sweating,weight loss of 1 year Oral glyceryl trinitrate provided no relief PE: heart rate:120 beats per minute; arrhythmia ECG: atrial fibrillation; ST-Tchange Diagnosis:coronary heart disease;atrial fibrillation
Is it an accurate diagnosis ?
★Thyrotoxicosis
Atrial Fibrillation
The causes of atrial fibrillation
InfectionsPulmonary disease
Neurogenic AF
Alcohol Drugs Electric shockSurgery......
Heart
Atrial fibrillationAngina pectoris
SweatingWeight lossheart rate increased
Thyroid funtion ?
FT3>46.08pmol/LFT4 67.5pmol/LTSH < 0.0025μU/LTRAb>40IU/LTGAb 14.51IU/LTPOAb 737.14
thyrotoxicosis induced cardiovascular dysfunction
Thyrotoxicosis induced cardiovascular dysfunction
• The morbidity of thyrotoxicosis induced cardiovascular dysfunction is about 5 %~ 10 % .
• Graves disease is the most common cause of thyrotoxicosis accounting for 60% to 90% of cases.
• Clinical classification: • 1) Hyperthyoidism as an initial cause;• 2) Hyperthyoidism as a worsen factor when patient has
underlying cardiac disease.
Clinical manifestationHypermetabolism syndrome:Weight loss with increased appetiteWarm and sweatingCoarse tremor in extremities,etc.
Cardiac symptoms in an early stage :Palptations, Exercise intolerance,Dyspnea on exertion, Tachycardia,etc.
Heart complication :Atrial fibrillation, Cardiomyopathy, Heart failure, Angina pectoris and Myocardial infarction.
The patient presents
SweatingWeight loss
Palpitationschest distress
Atrial fibrillationAngina pectoris
Thyrotoxicosis induced cardiovascular dysfunction
Diagnostic criteria ?
① Atrial Arrhythmias, enlarged heart or ventricular failure②Clinical manifestations and biochemical proof of Hyperthyroidism③After specific treatment ,the above-mentioned can disappear
NYHA(New York Heart Association)
Chinese scholars’ consensus Along with hyperthyroidism ,
One having at least one item of heart abnormality can diagnosed hyperthyroidism heart disease :①enlarged heart ;② Arrhythmias ;③ congestive heart failure ;④ Angina pectoris and myocardial infarction ;
Meanwhile , another factors changing heart functions should be excluded
Rarely, young patients with thyrotoxicosis may have chest pain similar in almost all respects to angina pectoris.
Thyrotoxicosis induced cardiovascular dysfunction
What type of thyrotoxicosis induced cardiovascular diseases is the patient ?
Types: Arrhythmia type Heart failure type Cardiomyopathy type
Thyrotoxicosis induced cardiovascular dysfunction
Arrhythmia Type Atrial fibrillation is the most common arrhythmia. The incidence is about 10%~20% hyperthyroidism patients. Heart failure Type Present in 6% of cases. It can be divided into high output failure and
pump failure. Risk factors: Age > 60, long term uncontrolled
hyperthyroidism,underlying heart disease and AF .
Cardiomyopathy Type: (rare) Rate-related cardiomyopathy: Tachycardiainduced cardiomyopathy can
cause heart failure, although LVEF usually normalizes after heart rate or rhythm control.
Dilated cardiomyopathy: Associated with Graves disease might have an auto-immune origin.
Thyrotoxicosis induced cardiovascular dysfunction
In patients with hyperthyroidism :Morbidity of AF is 8.3%Male sex, increasing age, ischemic heart disease, congestive heart failure, and heart valve disease are associated with an increased risk of AF
Arch Intern Med. 2004;164:1675-1678
Mechanisms
★ The heart is main target organ of Thyroid Hormone.
T3 influence cardiac action by three different routes:
1) T3 exerts a direct effect on cardiac myocytes;
2) T3 may influence the sensitivity of the sympathetic system; 3) T3 leads to periphery hemodynamic changes.
Thyrotoxicosis induced cardiovascular dysfunction
T3 effects on the cardiac myocyte
Genomic nuclear effects:T3 binds to nuclear thyroid hormone receptors (TRs), combined with recruited cofactors.The complex then bind or release specific sequences of DNA , modifying the rate of transcription of specific cardiac genes.
Non-genomic effects:T3 direct modulate the transport of ions (calcium, sodium and potassium) across the plasma membrane, glucose and amino acid transport,mitochondrial function and various intracellular signalling pathways.
Regulated cardiac gene as reported
Interactions between THs and the sympathetic system
Some T3 effects are mediated by an increased activity of the sympathetic system or an increased responsiveness and sensitivity of cardiac tissue to normal sympathomimetic stimuli.
The enhanced sympathetic sensitivity of the hyperthyroid heart may be mediated by an increased number of β-adrenergic receptors.
Haemodynamic changes
SV
R d
ecreases
T3
vascular smooth muscle cells
endothelialcell
nongenomic
genomic
membraneion channels
NO
NO
paracrine manner
vascular
relaxation
T3 relaxs vascular smooth muscle cells though regulation of nitric oxide ( NO), and decreases peripheral resistance.
only 50% of hyperthyroidism patients with congestive heart failure have impaired left ventricular (LV) systolic function . LV diastolic dysfunction may involve in the remaining half.
The patient has been confirmed , and how to treat it ?
Thyrotoxicosis induced cardiovascular dysfunction
Management and Treatment
• Principle:• ①Recover the thyroid function as soon as
possible.To rapidly reduce the actions of thyroid hormone, ATDs and Radioiodine is recommended;
②Acute treatment of cardiac complications;
• Most patients who get immediate control of hyperthyroidism, can self-recover cardiac disorders gradually.
Thyrotoxicosis induced cardiovascular dysfunction
Therapy of atrial fibrillation
• Control the thyroid function
• About 50% AF in young and new onsets can convert to sinus rhythm after keeping euthyroid for 6~12 months.
• Those AF consisting for more than 4 months after euthyroid , Drugs and Electroversion can be considered.
• Anticoagulative therapy is recommended in the absence of a specific contraindication, at least until a euthyroid state has been restored and heart failure has been cured.(ACC/AHA)
Therapy of heart failure
• Control the thyroid function;
(The treatment of HF follows its conventional therapy. )• Expectant treatment: Sedation, oxygen uptaking, sodium
limiting , etc.• β-blokers is used to stable the heart rate• Digitalis and Diuretic can effectively relieve heart burden
and pulmonary congestion symptoms. However it is hard to restore totally.
• Dosage of Digitalis is greater than usual loading and maintenance dosage maybe needed.
Thyrotoxicosis induced cardiovascular dysfunction
Case 2 A 60-year-old male patient Palpitations, fatigue, weakness, weight loss of 1 month's duration The patient had been taking amiodarone for 2.5 years for
non-sustained ventricular tachycardia episodes. amiodarone had been discontinued for six months PE: heart rate:98 beats per minute
what about thyroid function?
laboratory analysis:FT3 : 20.08pmol/L FT4 : 44.5pmol/L TSH : 0.083U/L
Is it Amiodarone-Induced Thyrotoxicosis?
Amiodarone-Induced Thyrotoxicosis(AIT)
• The incidence of AIT reported in different studies varies
but remains within the range of 5–10% in most studies.• AIT may develop suddenly and early or after many years of
treatment, the usual time period is 2–47 months;• AIT may also develop many months after drug withdrawal.
Iodine deficient individuals render more sensitive to exogenous iodine
Risk factors: female sex, complex cyanotic heart disease, previous Fontan type surgery, and a total daily dose above 200 mg
Why does Amiodarone can Induce Thyrotoxicosis?
Types
★ Some patients exhibit a mixed pattern
• The decision to stop amiodarone in the setting of thyrotoxicosis should be determined on an individual basis in consultation with a cardiologist, based on the presence or absence of effective alternative antiarrhythmic therapy.
Is it need for amiodarone discontinuation?
The need for amiodarone discontinuation is controversial, because :
(1) This drug is frequently the only medication able to control
cardiac arrhythmia, (2) The effects of this fat soluble drug may persist for many
months.(3) Amiodarone may have T3-antagonistic properties and
inhibit T4 to T3 conversion, withdrawal Amiodarone may aggravate cardiac manifestations of thyrotoxicosis.
(4) AIT typically resolves even if amiodarone therapy is continued.
Conclusion: a: Euthyroidism was reached despite continuation of amiodarone in all patients. b: Prednisone remains the preferred treatment of AIT type 2.
Thyrotoxicosis and Pregnancy
• Effects On Cardiovascular hemodynamics are additive
Mother: spontaneous abortion, hyperthyroidism crisis, heart failure, preeclampsia, premature delivery, etc;
Fetus: stillbirth, Growth restriction, goiter, heart failure, etc;
• It is more urgent to control thyroid function and monitor heart function.
There is no evidence of teratogenesis following maternal exposure to beta-blockers in the first trimester.
The risk of IUGR associated with maternal use of beta-blockers exists , use the smallest effective dose (avoiding large doses) and use is limited to the third trimester.
There is also a theoretical risk of neonatal bradycardia, hypotension and hypoglycaemia if beta-blockers are used up to the time of delivery.
Use β-blocker Cautiously in pregnancy
Take Home Message
• In clinics, the patient's history and thyroid function tests are important. (monitor)
• The first step for treating heart complications is hyperthyroidism control. (treatment)
• It is important to take risk factors into account, such as age, sex, hyperthyroidism type, underlying health problems. (prevention)
Thank you!Thank you!