Cardiovascular Disorders Flashcards
Describe the ECG findings of Wellens’ Syndrome. What coronary artery is usually affected?
Deep symmetric T-wave inversion in V2 and V3 is seen in about 75% of patients and biphasic T-waves in V2 and V3 is seen in about 25% of patients. The T-wave abnormality may also extend to lead V4
Critical stenosis of the left anterior descending artery
What is the initial ECG abnormality in patients with “torsades de pointes” a variant of polymorphic ventricular tachycardia?
Prolongation of the QTc interval.
QTc interval > 500 msec clearly increases risk for torsades
2-3 times higher in women than in men, account for 5% cardiac arrest .
Higher frequency in patients 35-50 years of age
In older patients, usually secondary to acquired long QT
Magnesium can be given at 1-2 g IV initially in 30-60 seconds, which then can be repeated in 5-15 minutes. Following conversion, a continuous infusion can be started at a rate of 1-2 g/hr
Can degenerate into v-fib arrest
What are the common precipitating factors of torsades de pointes?
Occurs as a result of a PVC during repolarization (T wave) in the setting of prolonged QT
Pointes mnemonic
Phenothiazines
Organophosphates / other meds (antibiotics, antiemetics, antipsychotics)
cardiac Ischemia / intracranial bleed (late complication)
No known cause (idiopathic)
Type 1 antiarrhythmics
Electrolytes (hypo K, hypo Mg)
Syndrome of prolonged QT
Other causes: hypothermia, hydrocarbon toxicity, chloral hydrate toxicity
What are the therapeutic considerations for stable patients with torsades de pointes?
- Administer Mg 1-2 g IV over 15 min may follow with continuous IV infusion of 1-2 g/h
- Correct electrolytes if necessary
- Discontinuation of all QT prolonging drugs
- Increase HR
a. Isoproterenol is 1st choice
b. 2nd line: dobutamine, dopamine, epinephrine
c. Overdrive pacing at rate of 100-120/min if pharmacologic agents fail. - Lidocaine may also be of benefit because it can suppress the PVCs that initiate torsade and produces minimal effects on the QT-
What is the best initial therapy for the unstable patient with rapid atrial fibrillation?
Synchronized cardioversion
Two options exist for placement of paddles on the chest wall.
1st - anterolateral
2nd - anteroposterior
What is the initial therapy for symptomatic patients with hypertrophic cardiomyopathy (such symptoms include syncope, atypical chest pain, dyspnea, and lightheadedness)?
- Initiate beta blockers
- Calcium channel blockers if beta blockers are contraindicated
- Combination therapy if monotherapy with BB or CCB fails
-BB +Disopyramide
-CCB +Disopyramide
-BB +non-Dihydropyridine CCB - LV myomectomy for severe cases
- AICD needed for high risk patients (h/o cardiac arrest or sudden cardiac death in the family)
- Avoid ionotropic drugs and ACE-inhibitors
What are indications for endocarditis prophylaxis?
High risk conditions for endocarditis:
* Prosthetic heart valves and valve repair material
* Previous infective endocarditis
* Unrepaired cyanotic congenital heart disease
* Repaired congenital heart defect with prosthetic material or residual defects
* Cardiac transplant recipients with valvulopathy
* Prophylaxis for any of the above conditions in a patient that is going to be undergoing a major dental procedure (not for simple dental cleaning).
What are the contraindications to anticoagulant therapy for patients with DVT?
Absolute contraindications
* Active bleeding
* Severe bleeding diathesis or platelet count </= 20,000/mm3
* Neurosurgery, ocular surgery or intracranial bleeding within the past 20 days
Relative contraindications
* Mild to moderate bleeding diathesis or thrombocytopenia (plt count less than normal but >20,000)
* Brain metastases, endocarditis
* Recent major trauma
* Major abdominal surgery </= 2 days
* GI or GU bleeding </= 14 days
* Severe hypertension (i.e. systolic BP >200, or diastolic >120 at presentation)
What is the classic ECG finding in acute pericarditis
Widespread ST elevations and PR depression with ST depression in aVR
What ECG findings are typically found in acute digitalis toxicity?
Most common finding in digitalis toxicity is PVCs “Classic” findings include slow “regularized” atrial fibrillation (i.e. atrial fibrillation with complete heart block and junctional escape rhythm), or paroxysmal atrial tachycardia with variable block and slow ventricular rate also look for “digoxin effect” (slurred downstroke at the end of the QRS complex, i.e. “Salvador Dali mustache” appearance.
A 65-year-old woman with a PMH of CAD, CHF and renal insufficiency is brought in by ambulance for evaluation. Her medications include furosemide, digitalis, sublingual nitroglycerin and baby aspirin. According to family members, she has become progressively more confused and weak over the past few days and has not been eating well. The ECG shows a regular wide complex tachycardia with alternating QRS polarity (bi-directional ventricular tachycardia) and point of care laboratory evaluation reveals a potassium of 3.0. What is the most likely diagnosis?
Chronic intoxication with digoxin
What diganosis should be excluded in a post-syncope patient with an incomplete RBBB pattern and ST elevation in the right precordial leads
The Brugada Syndrome
Sodium channel dysfunction predisposes patients to ventricular fibrillation. Drug therapy is ineffective. Placement of an internal cardioverter defibrillator is indicated.
* Type 1: The elevated ST segment (≥2 mm) descends with an upward convexity to an inverted T wave.
* Type 2: The ST segment has a “saddle back” ST-T wave configuration, in which the elevated ST segment descends toward the baseline, then rises again to an upright or biphasic T wave.
What is the most common cause of right-sided CHF?
Left-sided CHF
Which conditions are most likely to predispose a patient to subacute bacterial endocarditis?
- Pre-existing valvular heart disease especially of the mitral and/or aortic valves. Mitral valve disease is most common.
- Injection drug use. The tricuspid valve (most commonly involved) is usually normal before onset of disease.
Note: murmur intensity can be variable
What are the reasons for the high mortality rate (>70%) seen in patients with mesenteric vascular occlusion?
- Delayed diagnosis: symptoms of mesenteric vascular occlusion can be non-specific and may mimic other digestive disorders
- Rapid pregression
- Comorbidities: patients with mesenteric vascular occlusion often have underlying comorbidities, such as cardiovascular disease, diabetes, or kidney disease
- Advanced age at which disease occurs has high frequency of comorbid disease (age >50 years old)
- Surgical complications
