Clinical manifestations and immune response to tuberculosis

Tuberculosis is a far-reaching, high-impact disease. It is among the top ten causes of death worldwide caused by a single infectious agent; 1.6 million tuberculosis-related deaths were reported in 2021 and it has been estimated that a third of the world's population are carriers of the tuberculosis bacillus but do not develop active disease. Several authors have attributed this to hosts' differential immune response in which cellular and humoral components are involved, along with cytokines and chemokines. Ascertaining the relationship between TB development's clinical manifestations and an immune response should increase understanding of tuberculosis pathophysiological and immunological mechanisms and correlating such material with protection against Mycobacterium tuberculosis. Tuberculosis continues to be a major public health problem globally. Mortality rates have not decreased significantly; rather, they are increasing. This review has thus been aimed at deepening knowledge regarding tuberculosis by examining published material related to an immune response against Mycobacterium tuberculosis, mycobacterial evasion mechanisms regarding such response and the relationship between pulmonary and extrapulmonary clinical manifestations induced by this bacterium which are related to inflammation associated with tuberculosis dissemination through different routes.

Spontaneous pneumothorax, with or without pulmonary cysts, in patients with COVID-19 pneumonia

INTRODUCTION

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) affects mainly the lungs causing pneumonia and complications like acute respiratory distress syndrome. Pneumothorax is a rare manifestation of the disease. This report is a description of a series of patients with COVID-19 and spontaneous pneumothorax, some of them with associated pulmonary cysts.

METHODOLOGY

Cases were collected retrospectively. We included clinical data from medical records and described radiologic findings. Patients that developed pneumothorax during mechanical ventilation were excluded.

RESULTS

Ten cases were included in this report, nine of them were male. The median age of our series was 62 years (IQR = 57-68). The median days since the onset of symptoms until the development of pneumothorax was 27 (IQR = 17-31), most cases developed after the second week of the diagnosis of pneumonia. Two cases required invasive mechanical ventilation, but pneumothorax occurred after ventilator weaning. Three cases showed subpleural pulmonary cysts.

CONCLUSIONS

Cysts and pneumothorax are rare manifestations of SARS-CoV-2 pneumonia with mechanisms not completely understood. This report highlights the role of CT scan in diagnosis of COVID-19 complications.

Cross-cultural adaptation of the Cambridge Pulmonary Hypertension Outcome Review for use in patients with pulmonary hypertension in Colombia

OBJECTIVE

To conduct a cross-cultural adaptation of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) as an instrument to evaluate the perception of symptoms, functional limitation, and health-related quality of life (HRQoL) in subjects diagnosed with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) in Colombia.

METHODS

The adaptation process involved 3 phases: translation, cognitive debriefing interviews, and a validation survey. To evaluate the psychometric properties, we recruited individuals ≥ 18 years of age who had been diagnosed with PAH or CTEPH to take part in the latter two stages of the adaptation process. All individuals were being followed on an outpatient basis by the pulmonary hypertension programs at Hospital Universitario San Ignacio, Fundación Clínica Shaio,and Clínicos IPS, all located in the city of Bogotá, Colombia.

RESULTS

A Spanish-language version of the CAMPHOR was developed for use in Colombia. The internal consistency was excellent for the symptoms, functioning, and quality of life scales (Cronbach's alpha coefficients of 0.92, 0.87, and 0.93, respectively). Test-retest reliability was above 0.70. The evaluation of the convergent validity and known group validity of the CAMPHOR scales confirmed that there were moderate and strong correlations with the related constructs of the Medical Outcomes Study 36-item Short-Form Health Survey, version 2, as well as showing their capacity to discriminate disease severity.

CONCLUSIONS

The Spanish-language version of the CAMPHOR developed for use in Colombia was the result of a translation and cultural adaptation process that allows us to consider it equivalent to the original version, having shown good psychometric properties in the study sample. Therefore, its use to assess the impact of interventions on the HRQoL of patients with PAH or CTEPH is recommended, in research and clinical practice.

Elliptic flow in Au+Au collisions at square root(S)NN = 130 GeV

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Occurrence of exercise-induced and spontaneous wide complex tachycardia during therapy with flecainide for complex ventricular arrhythmias: a probable proarrhythmic effect

Flecainide acetate, a new antiarrhythmic agent, possesses favorable pharmacokinetic and hemodynamic properties and demonstrates highly favorable antiarrhythmic activity in patients with ventricular arrhythmias. However, the proarrhythmic potential of flecainide deserves further evaluation. In 7 (13%) of 55 consecutive patients treated with oral flecainide, 200 to 600 mg/day, for complex ventricular arrhythmias (including sustained ventricular tachycardia in 14), we observed the appearance of new or more sustained exercise-induced (five patients) or spontaneous (two patients) wide complex tachycardia. The mechanism of wide complex tachycardia appeared to be ventricular tachycardia in all seven. In our series, episodes were self-remitting or successfully treated. In four patients, wide complex tachycardia did not recur during exercise testing during alternative antiarrhythmic therapy (three patients) or no antiarrhythmic therapy (one patient). These observations raise the possibility of flecainide-related proarrhythmia, manifested as an increased propensity to exercise (activity)-induced wide complex tachycardia, which was not reliably predicted by results of Holter recordings or programmed electrical stimulation. Patients with complex ventricular arrhythmias beginning long-term treatment with oral flecainide should be considered for treadmill exercise testing together with ambulatory monitoring as part of the initial assessment of drug efficacy.

High incidence of clinical and subclinical toxicity associated with amiodarone treatment of refractory tachyarrhythmias

Amiodarone has been hailed as the most effective single antiarrhythmic drug for treatment of refractory supraventricular and ventricular arrhythmias. However, questions continue to arise about its long-term potential toxicity and true efficacy rates. We, therefore, reviewed our experience with 78 patients, mean age 59 +/- 14 years, with drug refractory tachyarrhythmias treated with amiodarone. Sixty-two patients were treated for recurrent ventricular tachycardia or ventricular fibrillation, 4 for complex ventricular ectopy and 12 for supraventricular tachyarrhythmias. Patients have been treated for a mean of 9.9 months (range, 1 day to 39.1 months); 34(55%) continued to be successfully treated for ventricular tachycardia/ventricular fibrillation, 2 (50%) for complex ventricular ectopy and 5 (42%) for supraventricular tachyarrhythmias. Amiodarone toxicity was frequent, occurring in 57/72 patients (79%) who were treated for more than one week. Adverse effects led to drug discontinuation in 15 (21%), 3 because of pulmonary toxicity (1 in combination with neuropathy and another with drug-induced hepatitis); 2 because of chemical hepatitis; 1, confusion; 6, neuropathy; 2, arrhythmia exacerbation; 2, symptomatic bradycardia; and 1 because of impotence. Of the 62 ventricular tachycardia/ventricular fibrillation patients who were treated with amiodarone, 8 (13%) expired: 4 died suddenly and 4 from documented ventricular tachycardia during treatment. In contrast, of 16 patients who had discontinued amiodarone because of initial adverse effects or drug failure and were treated with alternative antiarrhythmic medications, 5 (31%) died suddenly. In conclusion, amiodarone appears to be fairly effective in high risk patients with refractory cardiac tachyarrhythmias but results in a rather high incidence of adverse effects in long-term follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Occurrence of ventricular arrhythmias in patients receiving acute and chronic infusions of milrinone

Milrinone is a promising new inotrope, but its arrhythmogenic potential has not been defined. We monitored ventricular arrhythmias during a 24-hour baseline and 48-hour milrinone infusion period in 12 patients with chronic heart failure. Patients were characterized by a mean age of 58 years and a left ventricular ejection fraction of 21%. Nine (75%) were male, nine had primary idiopathic dilated cardiomyopathy, and three had coronary artery disease. None had a history of cardiac arrest or sustained ventricular tachyarrhythmia. Milrinone was given as a loading dose (mean 53 micrograms/kg/10 min; range 37.5 to 75) followed by a 48-hour maintenance infusion (mean 0.53 micrograms/kg/min; range 0.25 to 0.75). Acutely, cardiac index increased by 27% and pulmonary wedge pressure decreased by 30% during milrinone; changes were maintained during continued therapy. Ventricular arrhythmia response was variable, with no significant overall difference. However, a trend toward increased ectopic activity was noted. No sustained tachyarrhythmias occurred. Mean frequency of premature ventricular complexes (PVCs) was 87 +/- 48 PVCs/hr (x +/- SEM) during baseline monitoring and 141 +/- 69/hr following infusion of the drug (p = 0.08). Mean frequency of couplets was 6.0 +/- 4.9/hr before drug infusion and 14.3 +/- 11.0/hr during infusion (p = 0.21). Mean frequency of runs was 0.9 +/- 0.8/hr before and 2.7 +/- 2.4/hr during drug infusion (p = 0.29). Two patients met criteria for proarrhythmia (increased PVCs of greater than 4x and/or repetitive forms of greater than 10x. However, neither proarrhythmia patient required reduction in the dosage of milrinone or additional antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Initial and long-term outpatient experience with pirmenol for control of ventricular arrhythmias

Pirmenol, a new class IA antiarrhythmic agent, has shown promise in short-term trials, but long-term efficacy has not been documented. We thus evaluated 11 patients with frequent (greater than or equal to 60/h) premature ventricular complexes (PVC) given oral pirmenol for 25-727 days. Ten of 11 patients entering the long-term open trial had shown greater than or equal to 70% (mean 83%) PVC suppression during in-hospital pirmenol dose ranging. Long-term pirmenol was given in divided doses of 100-600 mg/day. Mean PVC frequency during baseline was 13,078/24 h (range, 3,218-32,718); couplets averaged 481/24 h (1-2,829) and runs 45/24 h (0-334). Ambulatory monitoring was performed at 1, 3, 6, and 12 months, then semiannually. Mean absolute PVC suppression at 1 month averaged 75% (p less than or equal to 0.02). Median individual percentage PVC suppression was 94%. During the first 3 months, 8 patients (73%) continued to show a favorable response (greater than or equal to 70% suppression), and 3 had arrhythmia recurrence and were dropped. One responder was withdrawn after the onset of paroxysmal atrial fibrillation, and another early responder was withdrawn after 3 months because of arrhythmia relapse. Six patients have been treated for over 1 year, with 99% mean PVC suppression. Mean couplet and run frequencies at 1 month decreased by means of 76% (p less than or equal to 0.05) and 92% (p = 0.001) respectively. At 1 year, couplets were suppressed 99.8% and runs by 99.7% in the 6 patients remaining on pirmenol.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial automaticity-conduction disorder with associated cardiomyopathy

An unusually large family of European descent was afflicted over four generations by an automaticity and conduction disorder with an associated dilated cardiomyopathy of variable expression. Ten living members affected with the disorder and three presumed affected but dead members were identified. Typically, the disorder presented as a sinoatrial bradyarrhythmia/tachyarrhythmia syndrome, followed by atrial enlargement and, variably, ventricular enlargement and dysfunction. Three family members required pacemaker implantation. Longevity did not seem to be greatly affected, but the demonstrated potential for embolic cerebrovascular events stresses an associated morbidity. The familial incidence was best explained by autosomal dominant inheritance with incomplete penetrance (greater in males and usually occurring first in adolescence) and variable expressivity. The large size of the family, frequency and profile of disease manifestations and disease tracking through at least four generations are unusual features of the familial disease described.

Initial and long-term outpatient experience with lorcainide for suppression of malignant and potentially malignant ventricular arrhythmias

There is a need for effective, well-tolerated antiarrhythmic agents, particularly those effective by both intravenous and oral routes. Lorcainide, a new antiarrhythmic drug with such properties, was given long-term orally to 24 patients controlled initially with intravenous therapy--19 with frequent (greater than 1/min) complex premature ventricular complexes (PVCs) on a baseline 24-hour Holter monitor and five with ongoing sustained ventricular tachycardia (VT) or frequent paroxysmal sustained VT, for a mean of 13 months (range 0.03 to 39.4 months). Long-term lorcainide was given in divided doses of 200 to 800 mg/day (median 260, mean 269 +/- 90 mg/day). Response to long-term lorcainide therapy was assessed at a mean of both 26 days and 12.2 months. Frequency of PVCs on baseline averaged 13,490/24 hours (median 10,578, range 2,115 to 61,716); couplets averaged 309/24 hours (median 166, range 0 to 5,686), and runs averaged 33/24 hours (median 30, range 0 to 2,951). Median frequency of PVCs decreased by 94% (p much less than 0.001) and 97% (p less than 0.01) at the first and second lorcainide efficacy assessments, respectively. Couplets decreased by a median of 99% (p much less than 0.001) and 100% (p less than 0.005) at the first and second assessments, respectively. Runs were suppressed by a median of 100% at both evaluations (p much less than 0.001). Only three (16%) of the patients with complex PVCs failed to respond to therapy. No recurrence during lorcainide has been noted in the five patients with ongoing sustained VT or recurrent episodes of VT.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of intravenous lorcainide with lidocaine for acute therapy of complex ventricular arrhythmias: results of a randomized study with crossover option

There is a need for effective, well tolerated, intravenous antiarrhythmic agents. The effects of lorcainide, a new class I antiarrhythmic agent, were compared with those of lidocaine in a randomized parallel study with cross-over option in 30 hospitalized patients with frequent (greater than 1/min) complex ventricular arrhythmias. Lorcainide loading dose was 2 mg/kg (at 2 mg/min) supplemented, if needed, with 100 mg in 1 hour; maintenance dose was 8 mg/h. Lidocaine loading dose was 1 mg/kg (at 25 mg/min) supplemented, if needed, with 50 mg in 2 minutes; maintenance dose was 2 or 3 mg/min (as needed). Arrhythmias were compared for 2 hours before and after drug loading. Initially responding patients (minimum of 70% arrhythmia suppression) were continued on maintenance therapy for 24 hours. Patients initially failing or with later arrhythmia escape crossed over to alternating therapy (seven to lidocaine, nine to lorcainide). The median frequency of premature ventricular complexes decreased by 76% after lidocaine (p less than 0.05) and by 93% after lorcainide (p less than 0.001); this difference approached significance (p = 0.06). More than 95% arrhythmia suppression was achieved by lorcainide in 47% of patients and by lidocaine in only 13% (p less than 0.05). Couplets decreased by a median of 100% after lorcainide and by 89% after lidocaine. Couplets were eliminated in 62% of the patients after lorcainide and in 27% after lidocaine (p = 0.06). There was 100% suppression of runs of premature beats in 11 patients after lorcainide and 99% suppression in 10 patients after lidocaine.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized trial of low-dose beta-blockade therapy for idiopathic dilated cardiomyopathy

Beta-blockade therapy to improve survival in idiopathic dilated cardiomyopathy (IDC) has been both advocated and criticized. However, randomized studies have not been performed. Thus, 50 patients with IDC were randomized in pairs to standard therapy (C) alone or with beta blockade (BB). Beta-blockade therapy with metoprolol was titrated from 12.5 to 50 mg twice daily as tolerated (final average dose, 61 mg/day). Groups were comparable in age (C, 50 +/- 15 years; BB, 51 +/- 13 years), gender (C, 76% male; BB, 56% male), entry functional class (C, 2.8 +/- 0.8; BB, 2.7 +/- 0.7), and left ventricular ejection fraction (C, 27 +/- 12%; BB, 29 +/- 10%). Follow-up averaged 19 months (range 1 to 38). One subject in each group was lost to follow-up. There were 3 early BB dropouts (within 2 days) due to low-output syndrome (2 patients) or fatigue (1 patient). Eleven patients died. By intention to treat, 5 BB and 6 C patients died (difference not significant). By actual treatment, 3 BB patients died, including 2 late dropouts (at 0.2, 10 and 17 months), and 8 C patients died (at 2, 9, 9, 15, 18, 24, 29 and 32 months, p = 0.12). In additional, functional evaluation on follow-up (functional class, San Diego questionnaire and exercise time) all tended to favor those receiving BB. Low-dose BB is tolerated in 80% of IDC patients on a long-term basis. Those continuing to take BB have a good prognosis. Mortality in C patients, however, is less than in some retrospective studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term follow-up after intracoronary streptokinase for myocardial infarction: a randomized, controlled study

Intracoronary streptokinase (SK) may have beneficial effects on the in-hospital course of acute myocardial infarction (MI), but long-term outcome is unknown. We evaluated the outpatient course of 50 MI patients, randomly treated with either SK (n = 24) or standard therapy (n = 26), who presented within 2.7 +/- 0.7 hours of symptoms. Coronary reperfusion occurred in 19 (79%) SK patients. Survivors were followed for a mean of 18.7 months (range 11 to 28.5); information was current in 48 patients (96%). Both groups received antiplatelet therapy for 3 months. A total of five deaths occurred in the control group and two in the SK group, including one posthospital death in each. Nonfatal MIs totaled five in control patients and three in SK patients, including five posthospital MIs (three control, one SK). Differences in major events (death or nonfatal MI) favoring SK did not quite reach statistical significance (10 control vs 5 SK). Bypass surgery was performed in seven SK and four control patients (NS). Angina occurred in more control (15) than SK (six) patients (p less than 0.01), and more control patients used long-acting nitrates (14 control, three SK; p less than 0.01). Palpitations were noted by nine control and one SK patient (p less than 0.01), and documented late arrhythmias were present in four control patients and no SK survivors (p less than 0.05). Symptoms suggestive of heart failure were present in seven control and one SK patient (p less than 0.01); two control patients were hospitalized for failure. Use of beta blockers, calcium channel blockers, and other cardiac medications did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized trial of intravenous and intracoronary streptokinase in patients with acute myocardial infarction

The clinical effects of intravenous streptokinase in patients with acute myocardial infarction were compared with those of intracoronary streptokinase in a randomized, prospective study. Comparisons were also made with a historical control group. Fifty patients were entered into the study at 2.4 +/- 1.2 hr after onset of pain, and 27 were assigned to intravenous and 23 to intracoronary therapy. The doses of streptokinase averaged 212,000 U ic and 845,000 U iv (0.75 X 10(6) U/5 hr, n = 14 or 10(6) U/1 hr, n = 13). Results of studies of the two intravenous dosage schedules were similar and so were combined. Streptokinase was administered at 2.8 +/- 1.0 hr after onset of pain in the intravenous and at 4.3 +/- 1.4 hr in the intracoronary drug group (p less than .001). Convalescent (day 10) radionuclide ejection fractions were 54 +/- 14% for the intravenous and 50 +/- 16% for the intracoronary drug group. Change in ejection fraction from day 1 to 10 tended to be greater after intravenous drug: 5.1% (p less than .08) vs 1.2% (NS). Semiquantitative regional wall motion indexes in the infarct zone showed significant and similar modest improvement from admission to day 10 in both groups (p less than .02). Accelerated enzyme-release kinetics were noted after both therapies. Times of peak enzyme levels for patients on intravenous and intracoronary drug were, respectively, 12.5 +/- 5.0 and 11.5 +/- 4.3 hr for creatine kinase MB isoenzyme and 31.7 +/- 11.8 and 28.1 +/- 12.7 hr for lactic dehydrogenase (LDH). Peak LDH-1 level was lower in patients receiving intravenous drug than in the historical control group (p less than .05). Electrocardiographically summed ST segments diminished rapidly after therapy in both groups; Q wave development was similar and overall R wave loss was equivalent and less extensive compared with in historical control subjects. Infarct pain requiring morphine was diminished similarly in both treatment groups. Incidence of early arrhythmias and heart failure also did not differ. Posttherapy ischemic events and early surgery tended to be more common in the intracoronary group and bleeding was more common in the intravenous group. Intravenous drug did not decrease early hospital mortality (intravenous drug = 5, historical control = 4, intracoronary drug = 1); the differences in this parameter among groups were not significant. At convalescent angiographic evaluation, anterograde perfusion was present in 73% of those receiving intravenous and 76% of those receiving intracoronary drug.(ABSTRACT TRUNCATED AT 400 WORDS)

HLA A, B and DR typing in idiopathic dilated cardiomyopathy: a search for immune response factors

Several autoimmune diseases have been associated with increased frequencies of various histocompatibility antigen (HLA) types that may be linked to immune response genes. Idiopathic dilated cardiomyopathy (IDC) has been proposed as a disease with autoimmune features, but HLA associations have not been evaluated. We performed HLA typing in 37 consecutive patients with IDC. Patients with habitual alcoholism were excluded. Results showed that no single HLA type could account for most cases; IDC is a genetically heterogeneous disease. However, uneven distributions were noted for certain types. Haplotype frequency of B27 was 0.145 in patients vs 0.033 in 5,726 local control subjects (p less than 0.001). Other A and B frequencies (except A2) were evenly distributed. HLA DR typing also revealed differences. The DR4 locus was present in 54% (19 of 35) of patients, vs 32% (26 of 82) of blood bank control subjects (p less than 0.02). The associated relative risk of DR4 was 2.2 and the etiologic fraction 0.29. Sex, disease chronicity, functional class, ejection fraction and biopsy evidence of myocarditis did not distinguish DR4-positive from DR4-negative patients, but they were older (54 +/- 12 vs 42 +/- 14 years, p less than 0.02). Of note, 68% were positive for DR4 or B27, or both. HLA DR6Y was underrepresented; it was present in 9% (3 of 35) of patients, vs 26% (21 of 82) of control subjects (p less than 0.04). The relative risk of DR6Y was 0.27 and the preventive fraction 0.19. These associations will require independent confirmation. However, they suggest that genetically determined immune response factors associated with HLA loci may play a role in pathogenesis in certain patients with IDC.

Pirmenol for control of ventricular arrhythmias: oral dose-ranging and short-term maintenance study

The antiarrhythmic efficacy and safety of oral pirmenol hydrochloride were assessed during a controlled, dose-ranging and short-term maintenance study in 12 patients with frequent (greater than 480/8 hours) premature ventricular complexes (PVCs). Eleven patients (92%) responded favorably (greater than 70% PVC suppression) to a trial of different doses. Mean interval (8-hour) suppression of PVC frequency was 95% in these 11 and 86% in the entire group. Twenty-four-hour suppression was similar in responders (88%). Repetitive PVCs were essentially eliminated. The mean effective dose was 316 mg/day (105 mg/8 hours). The average predose (trough) plasma concentration at the end of dose ranging was 1.4 micrograms/ml and the drug elimination half-life 7.3 hours (n = 12). Of 11 responding patients, 10 completed a 2-week outpatient trial. Pirmenol continued to be effective and tolerated in 8 patients, maintaining an overall average outpatient PVC suppression of 80%. The electrocardiographic intervals were mildly prolonged after multiple dosing (PR + 7%, QRS + 12%, QTc + 8%; all p less than 0.01). Blood pressure and heart rate did not change during treatment. The echocardiographic ejection fraction was maintained. Thus, oral pirmenol appears to be effective, conveniently administered and well tolerated as an antiarrhythmic agent for control of ventricular extrasystoles.

A randomized trial of intracoronary streptokinase in the treatment of acute myocardial infarction

Fifty patients with acute myocardial infarction were randomly assigned to receive either intracoronary streptokinase or standard (control) therapy within about three hours after the onset of pain. Coronary perfusion was reestablished in 19 of 24 patients receiving streptokinase. Streptokinase alleviated pain (as indicated by differences in subsequent morphine use). The Killip class was significantly improved after therapy with streptokinase, as were changes in radionuclide ejection fraction between Days 1 and 10 in surviving patients (+3.9 vs. -3.0 per cent, P less than 0.01). The echocardiographic wall-motion index also showed greater improvement after streptokinase treatment (P less than 0.01). Streptokinase therapy was associated with rapid evolution of electrocardiographic changes, which were essentially complete within three hours after therapy, but loss of R waves, ST elevation, and development of Q waves in the convalescent period were greater in the control group (P less than 0.01). The time required to reach peak plasma enzyme concentrations was significantly shorter after streptokinase. The incidence of early and late ventricular arrhythmias was not affected by treatment. We conclude that intracoronary streptokinase appears to have a beneficial effect on the early course of acute myocardial infarction.

Disposition of intravenous pirmenol

Twelve patients having frequent premature ventricular complexes (PVCs) averaging more than 60 per hour received a single 150-mg intravenous dose of pirmenol. Plasma pirmenol concentration declined biexponentially following the infusion and was analyzed according to a two-compartment open model. Following an erratic distribution phase, the terminal elimination half-life ranged from 4.2 to 16.9 hours, with a geometric mean of 7.6 hours. Total body clearance averaged 164 +/- 58 ml/min, and the mean volume of distribution was 1.45 +/- 0.38 liter/kg. Renal clearance averaged 46.6 +/- 21.2 ml/min, representing 30 +/- 10 per cent of total body clearance. Excretion of unchanged drug in the urine averaged 31.8 +/- 8 per cent of the dose. Renal clearance and elimination half-life were correlated (r = -0.61, P less than 0.05). Eight of the 12 patients achieved greater than 95 per cent suppression of PVCs with a duration between 20 minutes and 23 hours. These favorable pharmacokinetics indicate that pirmenol may be a useful addition to the therapy of ventricular arrhythmias.

Response to encainide of refractory ventricular tachycardia: clinical application of assays for parent drug and metabolites

To assess the response to encainide in patients with malignant arrhythmias, we treated 22 patients with recurrent ventricular tachycardia (VT) or fibrillation (VF) refractory to an average of 5.7 drugs. Thirteen patients (59%) showed a favorable in-hospital response, and 11 of 22 (50%) maintained a favorable antiarrhythmic response during a median follow-up of 13.5 months (range 0.3--25.5). Encainide was well tolerated. Six (46%) of 13 patients responded to intravenous encainide with suppression of VT by programmed ventricular stimulation or continuous monitoring; oral encainide has maintained arrhythmia control. In six of seven others, cycle length of VT was lengthened. Initial therapy with oral drug yielded five complete and two partial responses, assessed by monitoring, among nine other patients. Of three outpatient failures, only one was an inpatient responder. Proarrhythmic responses were also noted and included spontaneous increases in ectopy (three patients), easier induction of VT spontaneously or at programmed stimulation (three patients), facilitation of exercise VT (one patient), and syncope due to VT/VF (one patient). After intravenous therapy, plasma encainide concentration averaged 773 ng/ml (range 476--1,279, n = 4), with low or negligible metabolites. During chronic oral therapy, encainide concentrations were low and variable, averaging 67.5 ng/ml (less than 10--585; n = 23, 10 patients); metabolite levels were higher and less variable: O-demethyl encainide, mean 198 ng/ml (61--882); 3-methoxy-o-demethyl encainide, mean 128 ng/ml (39--379). Active metabolites(s) may thus be more important than parent drug during chronic therapy. In summary, encainide may provide successful therapy in approximately half of patients with malignant, refractory ventricular arrhythmias. Inpatient response predicts outpatient results. Encainide, like other antiarrhythmics, has proarrhythmic potential, suggesting a carefully monitored initial approach.