Prognostic significance of the admission electrocardiogram in acute myocardial infarction.

OBJECTIONS: We sought to access the ST segment and the terminal portion of the QRS complex in the initial electrocardiogram (ECG) as tools to predict outcome in patients with acute myocardial infarction given thrombolytic therapy. BACKGROUND: Previous studies assessing early risk stratification of patients with acute myocardial infarction by ECG criteria have focused on the number of leads with ST segment elevation or the absolute magnitude of ST deviation. A new classification independent of the absolute values of ST deviation was pursued. METHODS: Patients with ST elevation and positive T waves in at least two adjacent leads who received thrombolytic therapy were classified into two groups based on the absence (1,232 patients) or presence (1,371 patients) of distortion of the terminal portion of the QRS complex on the admission ECG. RESULTS: There were no differences between groups in the prevalence of previous angina, hypertension, current smoking, anterior infarction, time from onset of symptoms to therapy of type of thrombolytic regimen. Patients with QRS distortion were less likely to have had a previous infarction (12.0% vs. 18.4%, p = 0.02) or diabetes mellitus (16.9% vs. 21.4%, p = 0.003). They had higher peak creatine kinase levels (1,617 +/- 1,670 vs. 1,080 +/- 1,343 IU, p = 0.00001). Hospital mortality for those with and without QRS distortion was 6.8% and 3.8%, respectively (p = 0.0008). Multivariable logistic regression analysis confirmed that hospital mortality was independently associated with distortion of terminal portion of the QRS complex (odds ratio 1.78, 95% confidence interval 1.19 to 2.68, p = 0.004). CONCLUSIONS: Distortion of the terminal portion of the QRS complex on the admission ECG is independently associated with a higher hospital mortality rate in patients with acute myocardial infarction given thrombolytic therapy.

Effect of metaraminol during acute inferior wall myocardial infarction accompanied by hypotension: preliminary study.

This study was designed to evaluate the effects of metaraminol (Aramine) in six patients with evolving acute inferior wall myocardial infarction accompanied by hypotension and warm limbs. There were 16 episodes of acute inferior wall ischemia, and the response to therapy was judged by evaluating blood pressure and ST segment and T wave abnormalities. Three patients received intravenous isosorbide dinitrate and two received streptokinase as the initial therapy. The mean ST segment elevation was significantly reduced (from 4.94 +/- 1 to 0.5 +/- 0.7 [p less than 0.0001]) after metaraminol infusion was initiated. The average T wave height also decreased (from 6.8 +/- 2 to -1.3 +/- 2.5 mm [p less than 0.0005]). The average heart rate decreased from 82 +/- 11 to 69 +/- 9 beats/min (p less than 0.05) and the mean arterial blood pressure increased from 81 +/- 12 mm Hg before metaraminol treatment to 126 +/- 8 mm Hg after treatment. All these changes occurred within a few minutes after metaraminol therapy was instituted. In 12 episodes, accelerated idioventricular rhythm appeared concomitantly with the resolution of ST segment elevation. Coronary angiography performed between 4 and 10 days after admission demonstrated significant obstruction in all infarct-related arteries, but none was totally occluded. Left ventricular function was normal in three patients and slightly hypokinetic in the inferior wall in two. These results indicate that in a selected group of patients with acute inferior myocardial infarction, metaraminol administration (in certain hemodynamic circumstances) can alleviate acute ischemia within a few minutes and thereby reduce ischemic injury.

Transient right axis deviation during acute anterior wall infarction or ischemia: electrocardiographic and angiographic correlation.

Eleven patients, three with acute anterior myocardial infarction and eight with anterior ischemia, who developed transient right axis deviation with a left posterior hemiblock pattern during the acute phase of myocardial infarction or ischemia are described (study group). A correlation between their electrocardiographic pattern and the angiographic findings was made. The arteriographic findings were compared with those of a group of 24 patients with acute anterior myocardial infarction or ischemia without transient right axis deviation (control group). The main electrocardiographic characteristics of the right axis deviation pattern were: an average shift of the mean frontal axis to the right of 42 degrees (10 degrees to 94 degrees); increased voltage of R waves in leads II, III and a VF and appearance of small Q waves or decreased voltage of Q waves if previously present in the same leads; decreased voltage of R waves and appearance of deep S waves in lead aVL; and inverted T waves and isoelectric ST segments in leads II, III and aVF. Coronary angiography revealed that the study group had a higher incidence of significant right coronary artery obstruction and collateral circulation between the left coronary system and the posterior descending artery than did the control group (100 versus 25% and 73 versus 0%, respectively; p less than 0.01). There were no differences between the groups regarding left anterior descending and circumflex artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic significance of precordial ST segment depression on admission electrocardiogram in patients with inferior wall myocardial infarction.

OBJECTIVES: This study assessed retrospectively the correlation between the pattern of precordial ST segment depression on the admission electrocardiogram (ECG) and hospital mortality in patients with an inferior myocardial infarction treated with intravenous thrombolytic therapy. BACKGROUND: Previous studies have shown that in acute inferior myocardial infarction, ST segment depression in the precordial leads is associated with increased hospital mortality. However, the significance of the different patterns of precordial ST segment depression has been evaluated in only two previous studies. METHODS: The study included 1,321 patients (1,020 men) who enrolled in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) trial in Israel and received intravenous thrombolytic therapy. Patients with an ST segment elevation > or = 0.1 mV in at least two of the inferior leads were included. Patients were classified into four groups on the basis of their admission ECG: group I = patients with no precordial ST segment depression (n = 346); group II = those for whom the sum of ST segment depression in leads V1 to V3 was greater than that in leads V4 to V6 (n = 700); group III = those for whom the sum of ST depression in leads V1 to V3 was equal to that in leads V4 to V6 (n = 162); group IV = those with maximal ST depression in leads V4 to V6 (n = 113). RESULTS: The overall hospital mortality rate was 3.6% (48 patients): for groups I, II, III and IV it was 2.9%, 2.8%, 4.3% and 9.7%, respectively. Multivariable logistic regression analysis confirmed that hospital mortality was independently associated with the pattern of precordial ST segment depression. The odd ratios in group IV relative to group I was 2.78 (95% confidence interval 1.26 to 6.13, p = 0.007). CONCLUSIONS: The risk of mortality is higher in patients with an inferior myocardial infarction and maximal ST segment depression in precordial leads V4 to V6 versus precordial leads V1 to V3 on the admission ECG.

Thrombolysis is an effective and safe therapy in stuck bileaflet mitral valves in the absence of high-risk thrombi.

OBJECTIVES: We sought to evaluate the effectiveness and safety of thrombolytic therapy in stuck mitral bileaflet heart valves in the absence of high-risk thrombi. BACKGROUND: Current recommendations for the thrombolytic treatment of stuck prosthetic mitral valves are partially based on older valve models and inclusion of patients in whom high-risk thrombi were either ignored or not sought for. The feasibility and safety of thrombolysis in bileaflet models may be affected by the predilection of thrombi to catch the leaflet hinge. METHODS: We studied 12 consecutive patients (men/women = 5/7, age 58.8 +/- 14.9 years) who experienced one or more episodes of stuck bileaflet mitral valve over a 33-month period and received thrombolytic therapy with streptokinase, urokinase or tissue-type plasminogen activator. Transesophageal echocardiography was performed in all patients. Patients with mobile or large (>5 mm) thrombi were excluded. Functional class at initial episode was I-II in 4 patients (33.3%) and III-IV in 8 patients (66.6%). RESULTS: Patients receiving thrombolytic therapy achieved an overall 83.3% freedom from a repeat operation or major complications (95% confidence interval 51.6-97.9%). Minor bleeding occurred in three patients (25%) and allergic reaction in one (8.3%). Transient vague neurologic complaints, without subjective findings, occurred in four patients (33.3%). Three patients had one or more relapses within 5.2 +/- 3.1 months from the previous episode, and readministration of thrombolytics was successful. CONCLUSIONS: In clinically stable patients with stuck bileaflet mitral valves and no high-risk thrombi, thrombolysis is highly successful and safe, both in the primary episode and in recurrence. The best thrombolytic regimen is yet to be established.

Persistent ST segment depression in precordial leads V5-V6 after Q-wave anterior wall myocardial infarction is associated with restrictive physiology of the left ventricle.

OBJECTIVES: To examine the relationship between the persistence of ST segment depression in leads V5-V6 after Q-wave anterior wall myocardial infarction (MI) and the filling pattern of the left ventricle (LV). BACKGROUND: Precordial ST segment depression predominantly in leads V5-V6 is associated with increased in-hospital morbidity and mortality after acute myocardial ischemia, perhaps due to reduced diastolic distensibility of the LV. METHODS: We prospectively studied 19 patients after Q-wave anterior wall MI (>6 months). All patients underwent 12-lead ECG recording, symptom-limited treadmill exercise testing with single photon emission computed tomography thallium-201 imaging, transthoracic Doppler echocardiography, cardiac catheterization and measurement of circulating atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels. Patients were classified based on the presence of ST segment depression in leads V5-V6: Group I = ST segment depression <0.1 mV (n = 10); Group II = ST segment depression > or =0.1 mV (n = 9). RESULTS: Patients in Group II had greater LV end diastolic pressures (32.4 +/- 6.5 mm Hg vs. 14.8 +/- 6.1 mm Hg; p = 0.0001), higher plasma ANP (44.4 +/- 47.1 pg/ml vs. 10.7 +/- 14 pg/ml; p = 0.04) and BNP levels (89.4 +/- 62.7 pg/ml vs. 23.6 +/- 33.1 pg/ml; p = 0.01), greater left atrium area (20.6 +/- 3.1 cm2 vs. 17.8 +/- 2.4 cm2; p = 0.05), lower peak atrial (A), higher early (E) mitral inflow velocities, a higher E/A ratio and a lower deceleration time (167 +/- 44 ms vs. 220 +/- 40 ms; p = 0.05). Lung thallium uptake during exercise was more common in Group II (78% vs. 10%, p = 0.04). CONCLUSIONS: Persistent ST segment depression in leads V5-V6 in survivors of Q-wave anterior wall MI is associated with increased LV filling pressure and a restrictive LV filling pattern.

Importance of the conal branch of the right coronary artery in patients with acute anterior wall myocardial infarction: electrocardiographic and angiographic correlation.

OBJECTIVES: This study assessed prospectively the correlation between the conal branch of the right coronary artery and the pattern of ST segment elevation in leads V1 and V3R during anterior wall acute myocardial infarction (AMI). BACKGROUND: The traditional electrocardiographic (ECG) definition of anteroseptal AMI-ST segment elevation in leads V1 to V3-has recently been challenged. The significance of ST segment elevation in lead V1 during anterior wall AMI is unclear. METHODS: The admission 12-lead ECG with additional lead V3R and the coronary angiograms performed within 10 days of hospital admission were evaluated in 28 consecutive patients (mean age +/- SD 62 +/- 9 years) admitted to the coronary care unit with anterior wall AMI. Patients were classified into two groups according to the magnitude of ST segment elevation in lead V1: group A (elevation > or = 1.5 mm, n = 12) and group B (elevation < 1.5 mm, n = 16). Two types of conal branch were identified: small (not reaching the interventricular septum [IVS]) and large (reaching the IVS). RESULTS: ST segment elevation in lead V3R was found in 11 (92%) and 6 (37%) patients from group A and group B, respectively (p < 0.001); a small conal branch was seen in 10 (83%) and 3 (19%) patients, respectively (p < 0.001). Ten patients (all from group B) had a large conal branch. CONCLUSIONS: ST segment elevation in lead V1 in the admission ECG of patients with anterior wall AMI is strongly related to ST segment elevation in lead V3R and is associated with a small conal branch. Our findings suggest that lead V1 reflects the right paraseptal area supplied by the septal branches of the left anterior descending coronary artery (LAD), alone or together with the conal branch. The absence of ST segment elevation in lead V1 during anterior AMI suggests that the IVS is protected by a large conal branch in addition to the septal branches of the LAD (double circulation).

Infarct site-related mortality in patients with recurrent myocardial infarction. SPRINT Study Group.

PURPOSE: The purpose of this study was to determine the effect of acute and old myocardial infarction (MI) sites on early (15 days) mortality in patients with a second MI. PATIENTS AND METHODS: Data are derived from the SPRINT 2 study population that included 1,161 consecutive patients with acute MI, aged 50 to 79 years, recruited from 14 coronary care units in Israel between November 1985 and July 1986. Two hundred twenty-six of these patients (19.5%) had a previous MI prior to the index acute MI. Sixty-two patients were excluded from the analysis either because the MI site was not of anterior or inferior location, or because of incomplete data. In the 164 (73%) remaining patients, acute and old MI locations were determined to be either anterior or inferior and were accordingly divided into 4 groups: acute anterior-old anterior (Group 1-23 patients); acute anterior-old inferior (Group 2-86 patients); acute inferior-old anterior (Group 3-34 patients); acute inferior-old inferior (Group 4-21 patients). RESULTS: Significant differences in clinical parameters among the four groups included a higher proportion of Q-wave MI (p = 0.04), severe congestive heart failure during admission (p = 0.04), and markedly elevated serum lactate dehydrogenase levels (p = 0.05) in Group 3. High-degree atrioventricular block (p = 0.001) and cardiogenic shock (p = 0.05) also developed more often in this group during hospitalization. Twenty-three patients (14%) died within 15 days. Death rates in the acute anterior (Group 1 plus Group 2) and the acute inferior (Group 3 plus Group 4) groups were 11% versus 20%, respectively (NS). However, death rate variability across the four groups was statistically significant (p = 0.018), with the highest mortality observed in Group 3 (old anterior-acute inferior MI-29%). Multivariate analysis identified acute inferior MI following old anterior MI as a strong independent predictor of early death (relative odds vis-à-vis other combinations 5.0, 95% confidence interval 1.5 to 16.6). CONCLUSION: This study identifies a subgroup of patients with acute inferior MI at high risk for early mortality. It is possible that such patients would benefit from early reperfusion therapy.

Usefulness of dobutamine radionuclide ventriculography for prediction of left ventricular function improvement after coronary artery bypass grafting for ischemic cardiomyopathy.

Ventricular function may improve after coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy depending on the amount of contractile myocardial reserve. Based on the studies using dobutamine echocardiography to predict regional wall improvement after revascularization, we investigated the benefit of low-dose dobutamine radionuclide ventriculography for assessing functional contractile reserve in this population. The study group included 56 patients with ischemic cardiomyopathy (mean left ventricular [LV] ejection fraction [EF] of 23 +/- 5%) and multivessel disease, who were referred for viability assessment. All underwent radionuclide ventriculography before and during infusion of 5 and 10 microg/kg/min of dobutamine. An increase in global LVEF from rest to dobutamine was calculated, and 10% was considered the cutoff value to predict ventricular improvement after CABG. Of the 35 patients who underwent CABG 1 month later, 29 were available for repeated radionuclide ventriculography after 12 +/- 5 months. Of these, 15 showed improvement (delta LVEF > or = 5%, mean 10 +/- 5%) and 14 did not (delta LVEF < 5%, mean -1 +/- 3%). The increase in EF with dobutamine had the highest univariate predictive value of all parameters evaluated. The sensitivity, specificity, and positive and negative predictive values of dobutamine radionuclide ventriculography were 67%, 93%, 91%, and 72%, respectively. We conclude that dobutamine radionuclide ventriculography is a useful method to assess contractile reserve and predict ventricular functional improvement after CABG in patients with ischemic cardiomyopathy.

New electrocardiographic criteria for predicting either the right or left circumflex artery as the culprit coronary artery in inferior wall acute myocardial infarction.

Two readily obtainable measurements on the admission electrocardiogram-a higher ST-segment elevation in lead III than in lead II and a greater ST-segment depression in lead aVL than in lead I-can distinguish right coronary artery from left circumflex artery-related acute inferior wall myocardial infarction.

Long-term follow-up of postmyocardial infarction patients with ventricular tachycardia or ventricular fibrillation treated with amiodarone.

Amiodarone in a low dose (200 mg/day) was administered alone or in combination with other type I antiarrhythmic drugs as a first-line agent in 33 patients with ventricular tachycardia (VT) (n = 24) or ventricular fibrillation (VF) (n = 9) secondary to coronary artery disease with healed myocardial infarction. There were 30 men and 3 women (mean age 69 +/- 9 years). Left ventricular ejection fraction ranged from 16 to 45% (mean 29 +/- 8). Therapy was guided by the results of electrophysiologic studies without the use of a control study (without drugs). Predischarge electrophysiologic studies revealed inducible sustained VT in 8 patients (24%), nonsustained VT in 7 and noninducible VT in 18 patients. Mean follow-up time was 27 +/- 7 months. Eleven patients (33%) died, 5 suddenly (15%) and 6 from nonarrhythmic causes. Five patients (15%) had nonfatal recurrences of VT. Life-table analysis showed that arrhythmic recurrences or fatalities (VT or sudden death) were related to the results of the predischarge electrophysiologic studies and not to the baseline arrhythmia (VT or VF). Toxicity from amiodarone was uncommon and no patient discontinued taking the drug.

Prognostic significance of maximal precordial ST-segment depression in right (V1 to V3) versus left (V4 to V6) leads in patients with inferior wall acute myocardial infarction.

This study examines whether patients with inferior wall acute myocardial infarction (AMI) and maximal ST-segment depression in left precordial leads are at higher risk for in-hospital mortality. The charts of patients (n = 213) with inferior wall AMI and an initial electrocardiogram that displayed peaked, tall T waves or ST-segment elevation with upright T waves in inferior leads were reviewed, after excluding patients with inverted T waves in inferior leads (n = 75). ST-segment deviation from baseline was measured for all leads. Patients were classified into 3 types: I = no precordial ST-segment depression; II = sum of ST-segment depression in leads V1 to V3 equal to or more than the sum of ST-segment depression in leads V4 to V6; and III = maximal precordial ST-segment depression in leads V4 to V6. Thirty-six patients (17%) died in the hospital. In-hospital mortality rates for patients with types I and II were 12% and 10%, respectively, compared with 41% for those with type III (p < 0.0001). Mortality rates in surviving patients were similar for all types up to 1 year after infarction. Multivariate logistic regression models for in-hospital mortality by ST-segment depression type adjusted for age, previous AMI, diabetes mellitus, and thrombolytic therapy revealed that type III pattern was a strong predictive factor for in-hospital mortality (odds ratio = 4.9, p = 0.0008, 95% confidence interval 1.93 to 12.26). Thus, patients with inferior wall AMI and maximal precordial ST-segment depression in leads V4 to V6 are at high risk for in-hospital mortality.

Clinical significance and predisposing factors to symptomatic bradycardia and hypotension after percutaneous transluminal coronary angioplasty.

Of 180 consecutive patients who underwent uneventful percutaneous transluminal coronary angioplasty (PTCA), 25 (13.9%) had at least 1 episode of symptomatic bradycardia and hypotension during the early postprocedure period. Symptomatic bradycardia and hypotension occurred 1 to 10 hours (mean 4 +/- 2) after PTCA. A higher incidence of symptomatic bradycardia and hypotension was found in patients receiving regular treatment with beta blockers (26% vs 10% in patients without beta blockers in their regimen, p < 0.01), diltiazem or verapamil (20% vs 9%, p < 0.025), or both a beta blocker and diltiazem or verapamil (64% vs 11%, p < 0.001). A higher incidence was also associated with angioplasty of the left anterior descending coronary artery compared with angioplasty of the other coronary arteries (22% vs 8%, p < 0.01). It is concluded that symptomatic bradycardia and hypotension is a common occurrence after PTCA. The incidence is higher after PTCA to the left anterior descending coronary artery and in patients receiving diltiazem, verapamil, and beta-blocking agents; it is particularly high in patients receiving a combination of a beta-blocking agent and either diltiazem or verapamil.

Effects of isosorbide dinitrates intravenously in high doses over a short period in anterior acute myocardial infarction.

The effects of intravenous isosorbide dinitrate administered in high doses over a short period of time in 17 patients (14 men, 3 women, mean age 67 years) with anterior wall acute myocardial infarction were evaluated. Patients were classified into 2 groups based on the electrocardiographic pattern of acute ischemia. Patients presented with anterior acute myocardial infarction; an electrocardiographic pattern of third-degree ischemia demonstrated a more favorable electrocardiographic and radionuclear angiographic evolution than similar patients who presented with an electrocardiographic pattern of second-degree ischemia.

Admission clinical and electrocardiographic characteristics predicting in-hospital development of high-degree atrioventricular block in inferior wall acute myocardial infarction.

This study assessed the ability of simple clinical and electrocardiographic variables routinely obtained on admission to identify patients who are at high risk of developing high-degree atrioventricular (AV) block during hospitalization in 1,336 patients with inferior wall acute myocardial infarction (AMI). Patients were classified into 2 initial electrocardiographic patterns based on the J-point to R-wave amplitude ratio: pattern 1: those with J point/R wave <0.5 and pattern 2: patients with J point/R wave > or =0.5 in > or =2 leads of the inferior leads II, III, and aVF. High-degree AV block was found in 6.7% of patients (41 of 615) with pattern 1 versus 11.8% of the patients (85 of 721) with pattern 2 on admission electrocardiogram (p = 0.0008). Multivariate logistic regression analysis revealed that the only variables found to be independently associated with high-degree AV block were female gender (odds ratio [OR] 1.48; 95% confidence interval [CI] 0.98 to 2.23; p = 0.06); Killip class on admission > or =2 (OR 2.24; CI 1.43 to 3.51; p = 0.0004); initial electrocardiographic pattern 2 versus pattern 1 (OR 1.82; CI 1.22 to 2.21; p = 0.003); and absence of abnormal Q waves on admission (OR yes vs no 0.68; CI 0.44 to 1.05; p = 0.08). A simple electrocardiographic sign (J point/R wave > or =0.5 in > or =2 leads) is a reliable predictor of the development of advanced AV block among patients receiving thrombolytic therapy for inferior wall AMI.

Comparison of patients with inferior wall acute myocardial infarction with versus without ST-segment elevation in leads V5 and V6.

One hundred forty-one patients with first acute inferior wall myocardial infarction were examined. ST-segment elevation in precordial leads V5 to V6 was found in 34; 94% of them had "mega-artery" compared with 2% in those without ST-segment elevation in precordial leads V5 to V6.

Electrocardiographic criteria for predicting the culprit artery in inferior wall acute myocardial infarction.

Two patterns of the QRS complex in the lateral lead aVL on the admission electrocardiograms of patients with inferior wall acute myocardial infarction (AMI) were correlated with the culprit artery. S/R wave ratio < or =1/3 with ST depression < or =1 mm was found to be a sensitive and specific marker for left circumflex artery AMI, whereas S/R-wave ratio >1/3 with ST-segment depression >1 mm was suggestive of right coronary artery AMI.

Paroxysmal atrial flutter and fibrillation associated with preexcitation syndrome: treatment with ajmaline.

Ajmaline was administered intravenously to six patients with the Wolff-Parkinson-White syndrome for the acute management of paroxysmal atrial flutter (three patients) or fibrillation (three patients) with a fast ventricular response (over the accessory pathway). Ajmaline increased refractoriness in the accessory pathway in all three patients with atrial flutter and stopped the flutter in one. The drug completely abolished preexcitation in two of the three patients with atrial fibrillation, decreasing the means ventricular rate of 240 and 300 beats/min to 110 and 180 beats/min, respectively. In the third patient with atrial fibrillation, ajmaline increased refractoriness over the accessory pathway, decreasing the mean ventricular rate of 300 beats/min to 160 beats/min. In two patients ajmaline was continued as an intravenous maintenance infusion until sinus rhythm was restored. It is concluded that ajmaline is an effective drug for the acute management of atrial flutter or fibrillation with a fast ventricular response in patients with the Wolff-Parkinson-White syndrome.

Importance of left anterior hemiblock development in inferior wall acute myocardial infarction.

Of the 87 consecutive patients admitted with first inferior wall acute myocardial infarction, 17 had acute left anterior hemiblock. The appearance of left anterior hemiblock identified a specific group with more extensive coronary artery disease and suggests disease of the left anterior descending coronary artery.

Procainamide-induced polymorphous ventricular tachycardia.

Seven cases of procainamide-induced polymorphous ventricular tachycardia are presented. In four patients, polymorphous ventricular tachycardia appeared after intravenous administration of 200 to 400 mg of procainamide for the treatment of sustained ventricular tachycardia. In the remaining three patients, procainamide was administered orally for treatment of chronic premature ventricular contractions or atrial flutter. These patients had Q-T prolongation and recurrent syncope due to polymorphous ventricular tachycardia. In four patients, the arrhythmia was rapidly diagnosed and treated with disappearance of further episodes of the arrhythmia. In two patients, the arrhythmia degenerated into irreversible ventricular fibrillation and both patients died. In the seventh patient, a permanent ventricular pacemaker was inserted and, despite continuation of procainamide therapy, polymorphous ventricular tachycardia did not reoccur. These seven cases demonstrate that procainamide can produce an acquired prolonged Q-T syndrome with polymorphous ventricular tachycardia.