Ventricular Tachycardia in Acute Myocardial Infarction Clinical Features of 113 Patients A. Beryl Farfel, MD, Herman H. Ricketts, MD, and L. Julian Haywood, MD Los Angeles, California This study was undertaken to evaluate the clinical significance of until discharge. Direct write-out elec- ventricular tachycardia as a complication of acute myocardial infarc- trocardiographs were available but tion in a large public hospital. An analysis of the clinical, electro- memory loops were out. All arrhyth- mia records were obtained by manual cardiographic, therapeutic, and prognostic implications of this large activation of the monitor system by patient group is presented and several unique features emphasized. trained nursing or physician personnel. The records of 113 patients with ventricular tachycardia were reviewed. Age, sex, onset of symptoms, onset of Ventricular tachycardia is an impor- Methods ventricular tachycardia, type and char- tant complication of acute myocardial All patients admitted to the Coro- acteristics of ventricular tachycardia, infarction, and prior to continuous nary Care Unit of the Los Angeles- therapy, outcome, location of infarct, monitoring, the incidence of this County-University of Southern Cali- associated arrhythmias, and compli- arrhythmia was estimated as one to fornia Medical Center between Octo- cations were catalogued for each pa- two percent.1-6 This arrhythmia has ber 1966 and October 1968, formed tient. been recognized with much greater the basis of the study. Of 416 total frequency in coronary care units and patients, 330 (79.3 percent) were con- Definitions its incidence has been reported as ten sidered to have acute myocardial in- Ventricular tachycardia (VT) is de- to thirty percent.7-11 In the early farction. The average stay in the unit fined as three or more depolarizations phases of myocardial infarction, even was 7.8 days. in sequence from an ectopic ventric- higher incidences have been Criteria for the diagnosis of myo- ular focus exceeding 60 per min- noted.1 2,1 3 During the last decade, cardial infarction were at least two of ute.14 Three types may be distin- the introduction of closed chest mas- the following: (1) pathological Q guished, namely, extrasystolic, para- sage, electrical reversion, continuous waves associated with S-T segment systolic, and idioventricular.15 Extra- electrocardiographic monitoring, and elevation and subsequent evolutionary systolic ventricular tachycardia begins newer anti-arrhythmic drugs have changes of the S-T segment and T with an extrasystole and can be viewed greatly altered the clinical course and wave; (2) elevation of the serum glu- as a series of three or more ventricular prognosis of ventricular tachycardia. tamic oxaloacetic acid transaminase extrasystoles. Ventricular extrasystoles Much of the reduction in mortality (SGOT), creatinine phosphokinase are characterized by a fixed-coupling demonstrated in acute myocardial in- (CPK), and lactic acid dehydrogenase interval between the preceding sinus farction, treated in coronary care (LDH); and (3) a typical clinical his- initiated ventricular (QRS) complex units, can be attributed to the preven- tory. In the presence of left bundle and the ectopic QRS complex. In this tion, prompt recognition, and treat- branch block, a history compatible form of ventricular tachycardia, the ment of this arrhythmia.1 1 with myocardial infarction and en- inter-ectopic intervals between parox- zymatic changes were required as ade- ysms are not in multiples of the quate evidence. The onset of infarc- ectopic cycle length, indicating the tion was timed with the occurrence of absence of a parasystolic mechanism precordial chest pain or increased (Figure 1). severity and frequency of chest pain in Parasystolic ventricular tachycardia From the University of Southern California patients with pre-existing angina. is characterized by a variable coupling Medical Center, Los Angeles, California. Re- quests for reprints should be addressed to Continuous oscillographic monitor- interval and the inter-ectopic intervals Dr. L. Julian Haywood, Box 305, 1200 North State Street, Los Angeles, Calif ing was initiated immediately on ad- between paroxysms are in simple mul- 90033. mission to the unit and continued tiples of the ectopic cycle lengths JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 69, NO. 2, 1977 109 (Figure 2). The phenomenon of en- detect arrhythmias. (The incidence of minute). Second or third degree A-V trance block or "protection" is mani- other arrhythmias was comparable to block occurred in 17 patients, paced fested. units having memory write-outs). The rhythms in four, atrial fibrillation in Idioventricular tachycardia is an es- high incidence of occurrence may have seven, auricular flutter in two, and cape rhythm which is enhanced - an been influenced by some bias in pa- nodal rhythm in three. accelerated idioventricular rhythm' 6 tient selection for a small unit, in that Single episodes of ventricular tachy- (Figure 3). there was a tendency to select patients cardia occurred in 23 patients (20 Attempts were made to classify who were unstable as compared to percent) whereas recurrences were each episode of ventricular ectopic others. The patient population other- documented in 90 patients (80 per- rhythm into one of the above three wise was self defining. Ninety patients cent). types. (80 percent) experienced recurrent Congestive heart failure was diag- episodes of ventricular tachycardia. nosed if there was x-ray evidence of Therapy pulmonary venous engorgement or Lidocaine was successfully used as pulmonary edema, or clinical evidence Age and Sex the primary therapy in 75 patients in a of central venous pressure elevation. The patients ranged in age from 34 dosage range of 1 to 4 mg/min follow- Shock was considered to be present if to 86. The majority of patients were in ing a bolus of 25 to 100 mg depending there was persistent hypotension the sixth (31 ) and seventh (40) de- upon the frequency and duration of (systolic blood pressure less than 80 cades. Twenty-three patients were the ventricular tachycardia episodes. mm Hg), associated with oliguria, (less under the age of 50, and 19 patients In resistant cases, procainamide was than 20 cc urine output per hour), were over 70 years of age. Eighty-nine added to lidocaine either intravenously changes in sensorium, and evidence of were male and 24 were female. or orally, and in a few instances was peripheral vascular constriction, such used alone. An intravenous mixture of as cold, moist extremities. equal parts of lidocaine and procain- Results amide frequently worked when there Characteristics of Ventricular Tachy- was not a prompt response to lido- Onset of Symptoms cardia caine. Intravenous atropine (0.5 to 1 In those patients in whom the time The mode of onset of each episode mg) was the initial therapy in 13 of onset of infarction could reasonably of ventricular tachycardia was ana- patients, while quinidine orally was be estimated, there was no predilec- lyzed. All cases could not be classified used in four patients, usually as an tion for any particular eight-hour according to the criteria given. Seventy ancillary antiarrhythmic agent. period of the day. Similarly, the times patients had characteristics of extra- Thirty-three patients required elec- of onset of ventricular tachycardia systolic ventricular tachycardia, five of trical reversion. Potassium was used were evenly distributed throughout parasystolic ventricular tachycardia specifically to treat the arrhythmia in the 24-hour period. Most patients were and 14 of idioventricular tachycardia; two patients. Rarely used were admitted to the monitoring unit 24 episodes could not be clearly classi- diphenylhydantoin, magnesium sul- within eight hours after the onset of fied. Catheter pacemaker-induced or phate, bretylium tasylate, and pro- symptoms. Some patients were ad- related ventricular tachycardia was pranolol. In the presence of shock or mitted to the unit after an initial stay noted in five patients. In each of these acidosis, vasopressors and sodium bi- on another ward, either due to lack of five patients, the ventricular arrhyth- carbonate were also employed. Pace- space in the coronary care unit or to mia developed after catheter place- maker catheters were used as an ad- late recognition of the acute myo- ment, and in two disappeared after junctive mode of therapy in nine cardial infarction state. Ninety-three catheter repositioning. patients with recurrent ventricular patients had their initial documented The rate of ventricular tachycardia tachycardia. episodes of ventricular tachycardia exceeded 120 in 66 patients, was Sixteen patients reverted from the within 96 hours of the onset of between 100 and 120 in 17 patients, initial episode of ventricular tachy- symptoms. The highest incidence was and in 21 patients was less than 100. cardia spontaneously, and were not on the first day and declined there- Absolute regularity of rate was noted previously receiving therapy. Sixty pa- after. Fifty-seven percent occurred in one third of the patients. tients (53 percent) were receiving anti- within the first 48 hours. Ventricular ectopic beats were re- arrhythmic drugs at the time of onset corded in 105 patients (93 percent) of ventricular tachycardia (lidocaine, Incidence before the onset of ventricular tachy- procainamide, quinidine) usually for During this period, 416 patients cardia. Only six patients (5.3 percent) control of ventricular ectopic beats were admitted to the unit,