Ventricular Tachycardia During Acute Myocardial Infarction
Ventricular Tachycardia During Acute Myocardial Infarction
Chief Complaint: Chest pain, near syncope
History of Present Illness: Severe chest pain for about 4 hours; near syncope while awaiting arrival of ambulance
Past Medical History: Hypertension
Family History: Coronary artery disease
Age: 69
Gender: Male
Blood Pressure: 80/p mm Hg
Pulse: 200 bpm
Respiration: 24
General Appearance: Pale, diaphoretic
Chest and Lungs: Rales halfway up bilaterally
Cardiac Exam: Tachy S1, S2
This ECG (Figure 1), recorded in the emergency room, shows a wide complex tachycardia at 205 bpm. Wide complex tachycardias are more likely to be ventricular tachycardia (VT) than supraventricular tachycardia with aberrancy, and in this case, Brugada's criteria favor VT (no RS complex in any precordial lead). As the patient is hemodynamically unstable, cardioversion after IV sedation would be the recommended approach. A quick bolus of IV amiodarone (or lidocaine) is also reasonable, with cardioversion shortly thereafter if still in VT. Adenosine and verapamil can precipitate hemodynamic deterioration in patients like this.
(Enlarge Image)
Figure 1.
This ECG is recorded in the emergency room.
Synchronized cardioversion restores sinus rhythm (Figure 2).
(Enlarge Image)
Figure 2.
Synchronized cardioversion restores sinus rhythm. This ECG is recorded.
Commentary: The ECG suggests acute anterolateral myocardial infarction (MI). In addition to marked ST elevation, deep precordial Q waves have already evolved. IV lidocaine (or amiodarone) is reasonable for the first 24-48 hours; it is generally discontinued if there are no recurrent arrhythmias.
A proximally occluded left anterior descending coronary artery is opened and stented. The ejection fraction (EF) on echo is 25%.
In general, an ICD is not implanted when VT or ventricular fibrillation (VF) occurs so early in the course of acute MI. While long-term follow-up data are not available, relatively old data suggest that patients who present with sustained VT or VF early in acute MI and survive to hospital discharge have a survival similar to EF matched patients who did not have VT/VF. Note, however, that the follow-up period was not particularly long in these older trials. Many electrophysiologists do not find these data sufficiently reassuring. Prophylactic ICD implantation is generally deferred at least 40 days after acute MI, given the results of the DINAMIT trial. An external defibrillator vest (LifeVest) is quite reasonable to protect the patient during this time; if left ventricular function does not recover, prophylactic ICD implantation can then be carried out.
Initial Presentation
Chief Complaint: Chest pain, near syncope
History of Present Illness: Severe chest pain for about 4 hours; near syncope while awaiting arrival of ambulance
History
Past Medical History: Hypertension
Family History: Coronary artery disease
Physical Findings
Age: 69
Gender: Male
Blood Pressure: 80/p mm Hg
Pulse: 200 bpm
Respiration: 24
General Appearance: Pale, diaphoretic
Chest and Lungs: Rales halfway up bilaterally
Cardiac Exam: Tachy S1, S2
This ECG (Figure 1), recorded in the emergency room, shows a wide complex tachycardia at 205 bpm. Wide complex tachycardias are more likely to be ventricular tachycardia (VT) than supraventricular tachycardia with aberrancy, and in this case, Brugada's criteria favor VT (no RS complex in any precordial lead). As the patient is hemodynamically unstable, cardioversion after IV sedation would be the recommended approach. A quick bolus of IV amiodarone (or lidocaine) is also reasonable, with cardioversion shortly thereafter if still in VT. Adenosine and verapamil can precipitate hemodynamic deterioration in patients like this.
(Enlarge Image)
Figure 1.
This ECG is recorded in the emergency room.
Synchronized cardioversion restores sinus rhythm (Figure 2).
(Enlarge Image)
Figure 2.
Synchronized cardioversion restores sinus rhythm. This ECG is recorded.
Commentary: The ECG suggests acute anterolateral myocardial infarction (MI). In addition to marked ST elevation, deep precordial Q waves have already evolved. IV lidocaine (or amiodarone) is reasonable for the first 24-48 hours; it is generally discontinued if there are no recurrent arrhythmias.
A proximally occluded left anterior descending coronary artery is opened and stented. The ejection fraction (EF) on echo is 25%.
In general, an ICD is not implanted when VT or ventricular fibrillation (VF) occurs so early in the course of acute MI. While long-term follow-up data are not available, relatively old data suggest that patients who present with sustained VT or VF early in acute MI and survive to hospital discharge have a survival similar to EF matched patients who did not have VT/VF. Note, however, that the follow-up period was not particularly long in these older trials. Many electrophysiologists do not find these data sufficiently reassuring. Prophylactic ICD implantation is generally deferred at least 40 days after acute MI, given the results of the DINAMIT trial. An external defibrillator vest (LifeVest) is quite reasonable to protect the patient during this time; if left ventricular function does not recover, prophylactic ICD implantation can then be carried out.
