Premature ventricular contractions and ventricular tachycardia/fibrillation Flashcards
What are premature ventricular contractions
Ventricular contaction that occurs before the next SA beat occurs
T/F: PVCs should be treated aggressively
False: PVCs should get no treatment because unless there are significant side-effects present PVCs are benign and do not require therapy
When is a PVC considered complex
More than 5 PVCs per minute, Occuring in couplets/triplets, multiform: source come from differemt areas of the heart, EAD in which ventricular stimulus causes premature depolarizaton of cells that have not completely repolarized
T/F: Patients with complex PVCs and heart disease (coronary or structural) are at increased risk for death
True
What was learned about PVCs due to the CAST trial
Avoid AADs for suppression of PVCs, Avoid class 1c agents in patients with heart disease, Amiodarone and dofetilide can be used for patients with HF because they are mortality neutral, beta-blockers can be used as treatment
What is sudden cardiac death
Death due to cardiac causes, heralded by abrupt loss of consciousness within one hour of symptom onset
What are the two types of ventricular tachycardias and characteristics of both
Non-sustained VTach: Three or more consecutive PVCs lasting less than 30 seconds that terminate spontaneously
Sustained VTach: Three or more consecutive PVCs lasting greater than 30 seconds or lasts less than 30 seconds but requires termination due to hemodynamic compromise
What is usually the heart rate if a patient has Vtach, what are the symptoms
Greater than 100 beats/min/ dyspnea, syncope, palpitations
What are the Vtach risk factors
Sleep apnea, myocardial scarring, CAD, NIDCM, electrolyte abnormalities, hypertrophic cardiomyopathy
What is the difference in ECG characteristics between monomorphic Vtach and Polymorphich Vtach
In monomorphic the electrical impulse shows a uniform rhythm so each QRS complex looks identical while in polymorphic there are multiple foci causing QRS comlexes to vary in amplitude and duration
What is torsdae de pointes
A type of polymorphic Vtach in which the LENGTHEND QT INTERVALS alternate with long R-R intervals producing R-on-T hills
What are QTc prolongations in men, women, and a increased risk of Torsdae de pointes
Greater then 470 ms, greater than 480 ms, greater than 500 ms
T/F: When looking at an ECG if the T- peak is to the right of the midpoint of the R-R interval QT is prolonged
True
What are physiological condiations that cause torsade piontes/ pharmcological
myocarditis, MI, HF, hypokalemia, hypomagnesia, severe bradycardia/ Class 1a and Class 3 AAD
What are risk factors for drug-induced TdP
Concurrent QT- prolonging drugs, QTc greater than 500 msec, bradycardia, electrolyte disturbances, recent conversion from AFib, advanced age, structural heart disease
What drug or drug classes prolong QT intervals
Azole antifungals, Tricyclic antidepressants, Antipsychotics, AADs, SSRI/SNRIs, Antiemetics, antibiotics, arsenic
What antibiotics prolong QT intervals, what type of antiemetics, other drugs as well
Fluroquinolones, Macrolides Trimethoprim/ Dopamine antagonists and Serotonin antagonists/ Methadone, amantadine, ranolazine
What are characteristics of VFib
HR greater than 300 bpm, preceded by Vtach, may be secondary to MI, ABSENCE of pulse
T/F: If a patient has acute sustained ventricular tachycardia the pulse should be checked first and if there is not pulse the ACLS algorithm must be referred too
True
If a patient has acute sustained ventricular tachycardia and a pulse is present what should be done if they are hemodynamically stable
Give the patient a straw and have them blow through it for several seconds stimulating the vagus nerve to lower their HR, emerge face in cold water/ice for 10 seconds to slow the HR, Give amiodarone (IV/PO) and if there is no structural damage procainamide or flecanide can be used as well
If a patient has acute sustained ventricular tachycardia and a pulse is present what should be done if they are hemodynamically unstable
Synchronized DC cardioversion, the current will need to be applied at the peak of the R wave or during ventricular depolarization
If a patient has acute sustained ventruclar tachycardia and there is no pulse what should be done immediately, what acronym should be done after
CPR
Shock: Zap every 2 mins as needed
CPR: After shock pump
Rhythm check: check to see if the heart is pumping
Epinephine: 1mg IV/PO every 3 to 5 minutes
Antiarrhythmic Medications: Amiodarone first line for refractory VFib, pVTach, Lidocaine is 2nd line, Magnesium Sulfate is first line for TdP
Meds
How should torsade de pointes be treated, what if the TdP is accompanied by bradycardia
Magnesium sulfate for 15 minutes/ Make sure potassium is greater than 4 and magnesium is greater than 2/ give isoproterenol 2-10 mg.min continuous IV infusion
What are the treatment options of NSVT if the patient has no heart disease and is symptomatic, not symptomatic
Beta blockers, Non-DHP CCBs, Class 1c agents added to beta-blockers, ablation/ no treatment required
What are the treatment options of NSVT if the patient has heart disease (post-MI or HF)
Positive EP study that may lead to ICD for primary prevention and secondary prevention unless they have reversible cause of VT
If a patient has sustained VTach that recurs what are the options if the patient has heart failure, no heart failure
Amiodarone PLUS a beta-blocker, Sotalol
