Psychosocial factors are associated with sleep disturbances and evening chronotype among women: A brief report from the American Heart Association Go Red for Women Strategically Focused Research Network

OBJECTIVES

To evaluate associations between psychosocial factors and sleep characteristics commonly linked to cardiovascular disease risk among racially/ethnically diverse women.

METHODS

Women from the AHA Go Red for Women cohort (N = 506, 61% racial/ethnic minority, 37 ± 16years) were assessed using self-reported questionnaires. Logistic regression models were adjusted for age, race, ethnicity, education, and insurance.

RESULTS

Women with depression had ∼3-fold higher odds of short sleep (95%CI=1.69-4.61), 2-fold higher odds of poor sleep quality and obstructive sleep apnea risk (95%CI=1.42-3.70 and 1.34-4.24), 4-fold higher odds of insomnia (95%CI=2.42-6.59), and greater likelihood of having an evening chronotype (OR:2.62, 95%CI=1.41-4.89). Low social support was associated with insomnia (OR:1.79, 95%CI=1.18-2.71) and evening chronotype (OR:2.38, 95%CI=1.35-4.19). Caregiving was associated with short sleep (OR:1.73, 95%CI=1.08-2.77) and obstructive sleep apnea risk (OR:2.46, 95%CI=1.43-4.22).

CONCLUSIONS

Depression, caregiver strain, and low social support are significantly associated with poor sleep and evening chronotype, highlighting a potential mechanism linking these psychosocial factors to cardiovascular disease risk.

Increasing Uptake of Depression Screening and Treatment Guidelines in Cardiac Patients: A Behavioral and Implementation Science Approach to Developing a Theory-Informed, Multilevel Implementation Strategy

BACKGROUND

Depression leads to poor health outcomes in patients with coronary heart disease (CHD). Despite guidelines recommending screening and treatment of depressed patients with CHD, few patients receive optimal care. We applied behavioral and implementation science methods to (1) identify generalizable, multilevel barriers to depression screening and treatment in patients with CHD and (2) develop a theory-informed, multilevel implementation strategy for promoting guideline adoption.

METHODS

We conducted a narrative review of barriers to depression screening and treatment in patients with CHD (ie, medications, exercise, cardiac rehabilitation, or therapy) comprising data from 748 study participants. Informed by the behavior change wheel framework and Expert Recommendations for Implementing Change, we defined multilevel target behaviors, characterized determinants (capability, opportunity, motivation), and mapped barriers to feasible, acceptable, and equitable intervention functions and behavior change techniques to develop a multilevel implementation strategy, targeting health care systems/providers and patients.

RESULTS

We identified implementation barriers at the system/provider level (eg, Capability: knowledge; Opportunity: workflow integration; Motivation: ownership) and patient level (eg, Capability: knowledge; Opportunity: mobility; Motivation: symptom denial). Acceptable, feasible, and equitable intervention functions included education, persuasion, environmental restructuring, and enablement. Expert Recommendations for Implementing Change strategies included learning collaborative, audit, feedback, and educational materials. The final multicomponent strategy (iHeart DepCare) for promoting depression screening/treatment included problem-solving meetings with clinic staff (system); educational/motivational videos, electronic health record reminders/decisional support (provider); and a shared decision-making (electronic shared decision-making) tool with several functions for patients, for example, patient activation, patient treatment selection support.

CONCLUSIONS

We applied implementation and behavioral science methods to identify implementation barriers and to develop a multilevel implementation strategy for increasing uptake of depression screening and treatment in patients with CHD as a use case. The multilevel implementation strategy will be evaluated in a future hybrid II effectiveness-implementation trial.

Heart disease in women

In every year since 1984, cardiovascular disease has claimed the lives of more females than males. More than 450,000 women succumb to heart disease annually, and 250,000 die of coronary artery disease. Despite the proportions, most women believe they will die of breast cancer. The perception that heart disease is a man's disease and that women are more likely to die of breast cancer is alarming. Although women develop heart disease about 10 years later than men, they are likely to fare worse after a heart attack. The poorer outcomes are due, in part, to the failure to identify heart attack symptoms. Approximately 35% of heart attacks in women are believed to go unnoticed or unreported. However, because of increased age, women are more likely to have co-morbid diseases such as diabetes and hypertension. In women, not only is "tightness" or discomfort in the chest a warning sign, but in addition, nausea and dizziness are common indicators of myocardial ischemia. Other symptoms include breathlessness, perspiration, a sensation of fluttering in the heart, and fullness in the chest. In comparison to men, women are less likely to undergo tertiary care interventions such as cardiac catheterization, angioplasty, thrombolytic therapy, and bypass surgery; to participate in cardiac rehabilitation; and to return to work full-time after myocardial infarction. In the past, most research about treatments for heart disease focused on men, and gender differences have been ignored. Recent studies are enrolling enough women to test if there are differences between men and women in outcomes. One of the major areas of research relates to estrogen and hormonal replacement therapy to reduce the relative risk of heart attack and stroke. The Women's Health Initiative is a major NIH-sponsored trial that addresses the issue of primary prevention of cardiac disease by hormonal replacement therapy. The results will be available in 2004. The Heart Estrogen/Progestin Replacement Study (HERS), disappointingly, did not show a significant reduction of coronary events in women taking hormonal replacement therapy, nor did the Estrogen Replacement and Atherosclerosis (ERA) trial of 309 postmenopausal women who underwent coronary angiography. New insight into the role of vitamins, phytoestrogens and other natural sources, and selective estrogen receptor modulators may provide other options for management. Until then, modification of risk factors and healthy life style choices are recommended for reducing the risk of cardiac disease. In fact, the key to a healthy heart in the year 2000 appears closely tied to life style choices. Prevention of disease is the key, and current recommendations are simply to stop smoking, or do not start; treat and control blood pressure >140/90 mm Hg; manage elevated lipids by diet, exercise, and cholesterol-lowering medications (if necessary); treat diabetes; lose weight so that BMI is <25; walk for 20-30 minutes at least three times a week; and take an aspirin tablet daily.

Effect of age on the exercise response in normal postmenopausal women during estrogen replacement therapy

Postmenopausal estrogen replacement therapy (ERT) has been associated with a reduced risk of coronary artery disease (CAD). Whether this apparent cardioprotective effect is mediated by a cardiovascular benefit during exercise, however, has not been clearly defined. To evaluate rest and exercise variables with and without ERT, a randomized crossover trial was conducted in 23 postmenopausal women, ranging in age from 44 to 75 years, mean age 57+/-8 years. The rest and exercise variables were compared on ERT and during a drug-free period. The baseline measure was compared to the effects after 4 weeks of ERT and after 4 drug-free weeks. Echocardiographic treadmill exercise variables of heart rate (HR), blood pressure, rate-pressure product (RPP), and cardiac dimensions were determined at baseline and at the end of each treatment period. In response to ERT, there was a decrease in low-density lipoprotein (LDL) cholesterol (drug-free: 142+/-40 mg/dl, ERT: 124+/-34 mg/dl) and an increase in high-density lipoprotein (HDL) cholesterol (drug-free: 52+/-14 mg/dl, ERT: 62+/-15 mg/dl, both p<0.01). At rest, the study population had no overall significant change in HR, blood pressure, RPP, or left ventricular end-systolic and end-diastolic diameters when ERT was compared to the drug-free period. However, subjects with the fastest baseline resting HR had the greatest decrease in HR with ERT relative to the drug-free period (p<0.05). During exercise, ERT effected no change in peak HR, blood pressure, or RPP, although end-systolic diameter decreased slightly (p<0.05). With ERT, subject age correlated negatively with systolic blood pressure (p<0.05) and RPP (p<0.01); both blood pressure and RPP decreased in older subjects. In conclusion, ERT has differential effects dependent on baseline HR and age.

Effects of desipramine on autonomic input to the heart

OBJECTIVE

To examine the impact of age on the effects of desipramine (DMI) on autonomic input to the heart.

METHOD

Twenty-four-hour electrocardiograms were obtained from 42 subjects, aged 7 to 66 years, while off and on DMI. To obtain measures of autonomic input to the heart, heart rate variability was assessed via spectral analysis of RR interval variability.

RESULTS

DMI treatment was associated with a significant increase in 24-hour mean heart rate and significant decreases in RR interval variability in all spectral bands, including in the high-frequency band, which provides a measure of parasympathetic input to the heart. RR interval variability was greater in younger individuals both off and on DMI.

CONCLUSIONS

DMI treatment was associated with a marked decline in RR interval variability, indicating that DMI affects autonomic input to the heart. Specifically, DMI reduced parasympathetic input, which, in theory, may increase vulnerability to arrhythmias. However, the magnitude of DMI's impact on RR interval variability did not vary with age.

Cardiovascular effects of desipramine in children and adults during exercise testing

OBJECTIVE

In light of recent reports of sudden death in children being treated with desipramine (DMI), 3 of which were associated with physical exercise, the authors examined the effects of DMI on exercise in children and adults before and during DMI treatment.

METHOD

Before treatment, 22 subjects (9 children, 13 adults) participated in a graded treadmill exercise test. Outcome measures included exercise tolerance, cardiovascular, and electrocardiographic parameters at progressive intensity levels and serum norepinephrine (NE) levels before and after exercise testing. Subjects were then treated with DMI, titrated to an average DMI dosage of 3 mg/kg, and underwent repeated exercise testing.

RESULTS

DMI treatment was associated with a significant elevation of circulating NE levels in the pre-exercise assessment. Exercise tolerance was not affected by DMI, and blood pressure and heart rate effects were modest. The cardiovascular impact of DMI treatment was similar in children and adults. One 31-year-old subject exhibited a brief episode of ventricular tachycardia associated with exercise during DMI treatment.

CONCLUSIONS

DMI has only minor effects on the cardiovascular response to exercise, and these effects do not appear age-related. However, DMI may increase the risk of exercise-associated arrhythmias in rare individuals.

Development of a prototype for a Center for Women's Health at an academic medical center

The development of a centralized program in women's health is a challenge in a decentralized academic medical center and in the environment of healthcare transformation. The Center for Women's Health at the Columbia-Presbyterian Medical Center has allowed the clinical and educational abilities of an academic faculty interested in gender-specific health to operate in the delivery of coordinated care. Within the structure of an academic environment come advantages and unique opportunities for solving deficiencies in healthcare but also the need to overcome obstacles inherent in a large system. Flexibility and creative problem solving are key to meeting the challenges of the changing environment of healthcare. Here we describe ventures to develop a model program of clinical care and education in the gender science of women's health.

Cardiovascular effects of fluoxetine in depressed patients with heart disease

OBJECTIVE

The purpose of this study was to determine the cardiovascular effects of fluoxetine in depressed patients with cardiac disease.

METHOD

Twenty-seven depressed patients (26% of whom were female and whose average age was 73 years) who had congestive heart failure, conduction disease, and/or ventricular arrhythmia were studied in an open medication trial of fluoxetine, up to 60 mg/day, for 7 weeks. The main outcome measures were heart rate and rhythm measured by 24-hour ECG recordings, ejection fraction determined by radionuclide angiography, cardiac conduction intervals, and blood pressure. Baseline values were compared with those at weeks 2 and 7 of fluoxetine treatment. In 60 comparable patients, values of these same cardiovascular measures at baseline and after 3 weeks of treatment with a tricyclic antidepressant, nortriptyline, were also examined.

RESULTS

Fluoxetine induced a statistically significant 6% decrease in heart rate, a 2% increase in supine systolic pressure, and a 7% increase in ejection fraction. There was no effect on cardiac conduction, ventricular arrhythmia, or orthostatic blood pressure. Overall, 4% of the fluoxetine patients had an adverse cardiovascular effect. In contrast, nortriptyline treatment caused a significant increase in heart rate and orthostatic hypotension, and 20% of the nortriptyline-treated patients had an adverse cardiovascular effect.

CONCLUSIONS

In depressed patients with heart disease, fluoxetine treatment was not associated with the cardiovascular effects documented for the tricyclic antidepressants or with significant adverse cardiac events. However, limited conclusions about fluoxetine's cardiovascular effects and safety can be drawn from this study of only 27 patients monitored for 7 weeks.

Estrogen replacement, vascular distensibility, and blood pressures in postmenopausal women

The pathogenesis of blood pressure (BP) rise in aging women remains unexplained, and one of the many incriminating factors may include abnormalities in arteriolar resistance vessels. The aim of this study was to determine the effects of unopposed estrogen on arteriolar distensibility, baroreceptor sensitivity (BRS), BP changes, and rate-pressure product (RPP). We tested the hypotheses that estrogen replacement therapy (ERT) enhances arteriolar distensibility and ameliorates BRS, which leads to decreases in BP and RPP. Postmenopausal women participated in a single-blind crossover study; the participants of this study, after baseline measurements, were randomly assigned to receive estrogen (ERT) or a drug-free treatment with a 6-wk washout period between treatments. The single-blind design was instituted because subjects become unblinded due to physiological changes (i.e., fluid shifts, weight gain, and secretory changes) associated with estrogen intake. However, investigators and technicians involved in data collection and analyses remained blind. After each treatment, subjects performed identical autonomic tests, during which electrocardiograms, beat-by-beat BPs, and respiration were recorded. The area under the dicrotic notch of the BP wave was used as an index of arteriolar distensibility. The magnitude of the reflex bradycardia after a precipitous rise in BP was used to determine BRS. Power spectral analysis of heart rate variability was used to assess autonomic activity. BPs were recorded from resistance vessels in the finger using a beat-by-beat photoplethysmographic device. RPP, a noninvasive marker of myocardial oxygen consumption, was calculated. Repeated-measures analyses of variance revealed a significantly enhanced arteriolar distensibility and BRS after ERT (P < 0.05). A trend of a lower sympathovagal balance at rest was observed after ERT, however, this trend did not reach statistical significance (P = 0.061) compared with the other treatments. The above autonomic changes produced significantly lower systolic and diastolic BP changes and RPPs (P < 0.05) at rest and during isometric exercise. We conclude that short-term unopposed ERT favorably enhances arteriolar distensibility, BRS, and hemodynamic parameters in postmenopausal women. These findings have clinical implications in the goals for treating cardiovascular risk factors in aging women.

Call to action: cardiovascular disease in women

One third of women between the ages of 50 and 75 have cardiovascular disease, which accounts for more than 50% of all deaths among women annually. Cardiovascular disease not only is the leading cause of death among women; it is more lethal and less aggressively treated in women than in men. Twice as many women--505,440--die from heart disease as from all forms of cancer combined. Despite the compelling statistics, only 8% of women consider cardiovascular disease a personal health threat. The scenario is troubling because women appear to understand so little or to deny their cardiac risks and so not recognize their ability to control them. Clearly, there is an urgent and compelling need for physicians to take an active role in identifying health behaviors that may affect the risk of cardiovascular disease in their female patients. Dialogue between the physician and patient should begin early to foster preventive steps, and the communication and education must continue throughout the patient's life span. Cardiovascular risk factors, including cigarette smoking, physical inactivity, hypertension, elevated cholesterol, overweight, diabetes, and menopause, should be identified and addressed for all women.

Lack of effect of estrogen on rest and treadmill exercise in postmenopausal women without known cardiac disease

To assess the peripheral vascular effects of estrogen in women without coronary disease, normal postmenopausal women (mean age 56 +/- 8 years) participated in a randomized, crossover trial using treadmill exercise echocardiography, and received oral conjugated estrogen, 0.625 mg/day or underwent a drug-free period. There was no significant effect on heart rate, blood pressure, double product, left ventricular end-systolic and end-diastolic diameters, or electrocardiographic measures after estrogen. In contrast to the profound effects reported in patients with cardiac disease, oral estrogen in normal women does not bestow significant benefit on treadmill exercise echocardiographic variables at rest or during modest levels of exercise.

Atrial fibrillation and stroke: elucidating a newly discovered risk factor

Atrial fibrillation is the most common sustained arrhythmia reported in the United States; an estimated 1-2 million Americans have chronic nonvalvular atrial fibrillation. This disorder is associated with a substantial risk of stroke. Several recent studies provide evidence that anticoagulation therapy is indicated for stroke prevention in patients with nonvalvular atrial fibrillation after recovery from a minor stroke. Clinical and echocardiographic criteria help to identify those patients who are at especially high risk for thromboembolic stroke and are candidates for carefully controlled anticoagulation. In an effort to reduce the possibility of thromboembolic events following either chemical or electrical cardioversion, the American College of Chest Physicians has recently prepared guidelines for the use of anticoagulation in the conversion of atrial fibrillation. The efficacy of antiarrhythmic drug therapy for cardioversion is often difficult to assess. Furthermore, it is associated with major risks, including heart failure and exacerbation of arrhythmia, and minor risks, including systemic intolerance. A new National Institutes of Health trial, Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM), will clarify the true risks and benefits of antiarrhythmic therapy for conversion of atrial fibrillation to sinus rhythm. Patients who cannot tolerate drug therapy may benefit from interruption of conduction in the bundle of His, followed by implantation of a permanent pacemaker, the use of radiofrequency energy ablation, or the implantation of an atrial defibrillator. Some patients may benefit from surgical procedures, such as left atrial isolation, the corridor operation, and the maze operation.

Increased early mortality in women undergoing cardiac transplantation

BACKGROUND

To evaluate factors that explain sex differences affecting mortality after cardiac transplantation, a retrospective analysis of adult patients undergoing orthotopic cardiac transplantation was undertaken at the Columbia-Presbyterian Medical Center.

METHODS AND RESULTS

The study population consisted of 379 patients (75 women, 304 men) > or = 18 years of age who survived for > or = 48 hours after undergoing orthotopic cardiac transplantation between March 1985 and March 1992. The following were analyzed: incidence of death and treated rejection episodes, donor and recipient cytomegalovirus (CMV) matches, use of OKT3 induction therapy, and donor and recipient HLA mismatches. Women 49 +/- 12 years old and men 47 +/- 12 years old were characterized by differences in race and diagnosis. Women were more likely to be nonwhite (P < .01) and have idiopathic cardiomyopathy than were men (P < .01). A trend toward an increase in first-year rejection frequency was seen in women compared with men (P = .08). Overall actuarial survival was significantly reduced in women after transplantation (P < .05). At 36 months, female actuarial survival was 64 +/- 7% versus 76 +/- 3% for men (P < .05). The majority of patients in this study did not receive CMV prophylaxis. Univariate analysis revealed that only CMV(+) donor status and the use of OKT3 induction therapy affected survival in women. Multivariate analysis revealed a marked reduction in survival in female recipients of CMV(+) donors given OKT3 induction therapy. At 36 months, only 25% of women were still alive compared with 86% of women with neither risk factor (P < .001). Even without OKT3 induction there was markedly reduced survival in women with mismatched CMV status, ie, CMV(-) recipients of CMV(+) donors; 17% survival after 36 months versus 86% in women who were CMV(+) recipients (P < .05). Although at this institution during the study time period, CMV prophylaxis was not routinely employed and OKT3 induction was selectively used in higher-risk patients, conclusions regarding differences in outcome that are sex dependent are valid.

CONCLUSIONS

(1) Women are at risk for reduced actuarial survival up to 3 years after cardiac transplantation. (2) Univariate analysis shows that women are selectively at risk for death when receiving hearts from CMV(+) donors and after receiving OKT3 induction therapy. (3) Multivariate analysis reveals that women are at even greater risk for death when receiving hearts from CMV(+) donors in conjunction with OKT3 induction therapy. (4) In the absence of OKT3 use, the greatest risk of death occurs in CMV(-) women transplanted with CMV(+) donor hearts. (5) When female to male survival curves are compared, factors that influenced survival in women did not appear to be problematic in men.

Moricizine concentration to guide arrhythmia treatment: with attention to elderly patients

To test the relationship between plasma moricizine concentration and the electrocardiogram (ECG) and arrhythmia suppression, 17 symptomatic cardiac patients with 30 or more ventricular premature complexes per hour were studied. Seven patients were mature adults, less than 60 years of age; and ten were elderly adults, more than 60 years of age. During steady-state moricizine therapy, patients had plasma moricizine concentration determined over a dosing interval, and had standard 12-lead ECG and a 24-hour ambulatory ECG recorded. The mean moricizine dose was 215 +/- 29 mg every 8 hours; mean maximal moricizine concentration was 1.4 +/- 0.84 micrograms/ml; and mean t1/2 beta was 1.5 +/- 0.7 hours. Baseline age-related differences were found, including prolonged electrocardiographic intervals (PR and QRS) (P < .05), increased ventricular arrhythmias (P < .05), and reduction in creatinine clearance (P < .05) in the elderly. Compared with pretreatment values, PR (P < .05) and QRS (P < .05) prolongation was observed, and was more marked in elderly patients. Over a dosing interval, there were dynamic changes on the ECG that paralleled plasma moricizine concentration; that is, peak and nadir intact moricizine concentration occurred simultaneously with ECG changes: QRS and JTc prolonged (P < .05), and PR prolongation approached significance (P = 0.09). Suppression of ventricular premature complexes of 80% or more occurred in 15 patients, and ventricular tachycardia was abolished in 10 of 12 patients. Probit analysis revealed that the therapeutic antiarrhythmic concentration ranged from 0.20 to 3.6 micrograms/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of desipramine on autonomic control of the heart

OBJECTIVE

To assess the effects of desipramine (DMI) on autonomic control of the heart.

METHODS

Blood pressure, RR interval (the time between successive heart beats), and RR interval variability, a noninvasive measure of autonomic control of the heart, were assessed in 13 subjects younger than 30 years old.

RESULTS

DMI treatment was associated with an increase in blood pressure, a decrease in RR interval, and a decline in low and high frequency RR interval variability.

CONCLUSIONS

These preliminary data suggest that, in young people, DMI treatment produces a substantial decrease in parasympathetic input to the heart and an increase in the ratio of sympathetic to parasympathetic input, changes that in certain circumstances have been associated with an increased risk of arrhythmia. In exploring the cardiac effects of the tricyclic antidepressants (TCAs) in young people, the impact of TCAs on autonomic input to the heart should be examined.

Is doxepin a safer tricyclic for the heart?

BACKGROUND

Many clinicians believe that doxepin is the safest tricyclic with respect to cardiovascular effects. This belief has persisted for two decades despite the absence of rigorous prospective evaluation.

METHOD

To address this issue, the authors studied the cardiovascular effects of doxepin in 32 depressed patients with preexisting left ventricular impairment, ventricular arrhythmias, and/or conduction disease.

RESULTS

Doxepin (1) did not have a robust effect on heart rate, (2) did not adversely affect left ventricular function, (3) did have a significant antiarrhythmic effect, (4) slowed cardiac conduction, and (5) caused a significant increase in orthostatic hypotension. Five (16%) of the 32 patients dropped out due to cardiovascular side effects. The overall dropout rate was 41%.

CONCLUSIONS

The cardiovascular effects of doxepin in depressed patients with heart disease are comparable to those documented for imipramine and nortriptyline. Doxepin afforded no greater margin of cardiovascular safety; in fact, the drug was poorly tolerated by this patient population.

Time course of moricizine's effect on signal-averaged and 12 lead electrocardiograms: insights into mechanism of action

The mechanism of action of moricizine, a new antiarrhythmic agent used in the Cardiac Arrhythmia Suppression Trial, is incompletely characterized. In addition, because moricizine is extensively metabolized, plasma moricizine concentration has an unknown relation to myocardial drug effect. Signal-averaged and standard electrocardiograms (ECGs) were used to monitor moricizine's myocardial effects in 16 patients with frequent ventricular premature complexes taking 600 to 900 mg daily. Three signal-averaged ECG variables were measured: total filtered QRS duration (fQRS), root-mean-square voltage in the terminal 40 ms of the QRS complex (V40) and the terminal low amplitude duration less than 40 microV (LAS). At steady state, plasma samples were collected and serial recordings of signal-averaged and standard ECGs were taken at 0, 1, 2, 4, 6 and 8 h after moricizine administration. A 24 h ambulatory ECG was recorded throughout the test period. Moricizine prolonged the fQRS (p less than 0.05) and decreased the V40 (p less than 0.05) of the signal-averaged ECG and prolonged the QRS (p less than 0.05) and corrected JT (JTc) intervals (p less than 0.05) of the standard ECG. The time course of the signal-averaged and standard ECG variables paralleled plasma moricizine concentration; that is, the maximal changes occurred at 1 to 2 h and declined to time 0 values at 8 h. The maximal changes were: fQRS (+8%), V40 (-33%), QRS (+8%) and JTc (+4%). Thus, dynamic changes were observed for intraventricular conduction (fQRS, QRS) and ventricular repolarization (JTc) over the dosing interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular effects of bupropion in depressed patients with heart disease

OBJECTIVE

The cardiovascular effects of therapeutic plasma levels of tricyclic antidepressants in depressed patients with and without preexisting cardiac disease have been well characterized and include orthostatic hypotension and conduction delay. Bupropion, structurally unrelated to tricyclic antidepressants, is relatively free of cardiac side effects in depressed patients without cardiac disease. However, it is unknown whether bupropion is safe for depressed patients with preexisting heart disease, so the authors studied the cardiovascular effects of bupropion in such patients.

METHOD

The subjects were 36 inpatients with DSM-III major depression and preexisting left ventricular impairment (N = 15), ventricular arrhythmias (N = 15), and/or conduction disease (N = 21). The patients continued their cardiac drug regimens and received bupropion for 3 weeks (mean +/- SD dose = 442 +/- 47 mg/day). Cardiovascular functioning was measured by pulse, blood pressure, high-speed ECG, 24-hour portable ECG, and radionuclide angiography.

RESULTS

Although bupropion caused a rise in supine blood pressure, it did not cause significant conduction complications, did not exacerbate ventricular arrhythmias, had a low rate of orthostatic hypotension, and had no effect on pulse rate. However, bupropion treatment was discontinued for 14% of the patients because of adverse effects, including exacerbation of baseline hypertension in two patients.

CONCLUSIONS

The cardiovascular profile of bupropion may make this drug a useful agent in the treatment of the depressed patient with preexisting cardiovascular disease. Further studies, with longer durations of bupropion treatment and more subjects, are needed to confirm these findings.

Myocardial amiodarone and desethylamiodarone concentrations in patients undergoing cardiac transplantation

Myocardial amiodarone and desethylamiodarone concentrations were measured at multiple sites in the explanted heart in four patients who underwent cardiac transplantation. Patients were taking amiodarone, 200 to 400 mg/day (mean 300 +/- 115), for 88 to 428 days (mean 229 +/- 148). The mean cumulative dose was 58 +/- 21.3 g. Plasma amiodarone concentration in three subjects was 204, 312 and 419 ng/ml and desethylamiodarone concentration was 268, 513 and 880 ng/ml, respectively. Significant interindividual variability in myocardial concentrations of amiodarone and desethylamiodarone was observed (p less than 0.05). Mean myocardial amiodarone concentration ranged from 4 +/- 1.0 to 29 +/- 17.2 micrograms/g (p less than 0.05); mean desethylamiodarone concentration ranged from 22 +/- 8.8 to 141 +/- 102.5 micrograms/g (p less than 0.05). At each site, save for fat, myocardial desethylamiodarone concentration was higher than amiodarone concentration. Greater intraindividual variability was observed in myocardial desethylamiodarone compared with amiodarone concentration particularly in septal and scar tissue (p = NS). No significant relation was found between myocardial concentration and duration of treatment. In patients with significant ventricular disease, usefulness of plasma amiodarone and desethylamiodarone concentration to estimate myocardial concentration is limited by intra- and interindividual variability.

Low dose quinidine-mexiletine combination therapy versus quinidine monotherapy for treatment of ventricular arrhythmias

Low dose quinidine-mexiletine combination therapy was compared with quinidine monotherapy in 15 patients with frequent ventricular premature complexes and nonsustained ventricular tachycardia in a dose escalation cross-over study. Oral combination therapy was initiated with quinidine gluconate (165 mg) plus mexiletine (150 mg) every 8 h. If ventricular premature complexes were not suppressed greater than or equal to 80% and nonsustained ventricular tachycardia greater than or equal to 90%, the dose was increased to a maximum of 330 mg of quinidine plus 200 mg of mexiletine. Quinidine monotherapy was initiated with 330 mg and escalated to a maximum of 660 mg every 8 h if criteria for effectiveness were not met. Combination quinidine-mexiletine therapy suppressed 80% of ventricular premature complexes in 13 of 14 patients and suppressed 100% of episodes of ventricular tachycardia in 6 of 8 patients (mean quinidine dose 200 +/- 70 mg; mean mexiletine dose 146 +/- 24 mg every 8 h). The mean effective trough quinidine and mexiletine concentration was 1.0 +/- 0.7 and 0.9 +/- 0.4 microgram/ml, respectively. Monotherapy was less effective; that is, greater than or equal to 80% suppression of ventricular premature complexes was observed in 5 of 15 patients and 100% suppression of ventricular tachycardia in 2 of 9 patients. The mean quinidine monotherapy dose was 462 +/- 155 mg every 8 h; the mean quinidine concentration was 1.8 +/- 0.8 microgram/ml. Adverse systemic effects occurred in 3 patients on quinidine-mexiletine therapy and in 11 on quinidine monotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Indecainide compared with quinidine for chronic stable ventricular arrhythmias secondary to coronary artery disease or to cardiomyopathy

Indecainide, a new type Ic antiarrhythmic agent, and quinidine sulfate were compared in a randomized double-blind parallel study. Cardiac patients with greater than or equal to 30 ventricular premature complexes per hour hour received indecainide, 50 mg, or quinidine, 200 mg every 6 hours, and the doses were increased until more than 80% suppression was noted, adverse effects occurred or a maximal dose of 100 mg of indecainide or 400 mg of quinidine given every 6 hours. Efficacy was achieved in 8 of 10 taking indecainide (p less than 0.05) and 7 of 9 taking quinidine (p less than 0.05). At least 90% of episodes of ventricular tachycardia were suppressed in 4 of 7 patients taking indecainide and 1 of 4 taking quinidine. No adverse effects were observed in the 7 patients who responded to indecainide and the 4 who responded quinidine, resulting in short-term efficacy without adverse effects in 7 patients (70%) taking indecainide and 4 (44%) taking quinidine. The effective or maximal mean daily indecainide and quinidine doses were 190 +/- 32 mg and 1,022 +/- 291 mg, respectively; mean trough indecainide and quinidine concentrations were 617 +/- 247 ng/ml and 3.3 +/- 1.4 micrograms/ml, respectively. Indecainide prolonged mean PR and QRS intervals (p less than 0.05), but not QT and QTc intervals. Quinidine did not change PR or QRS intervals but prolonged QTc interval (p less than 0.05). During dosing, 1 patient discontinued indecainide treatment because of nausea; 3 discontinued quinidine because of gastrointestinal complaints.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular effects of imipramine and bupropion in depressed patients with congestive heart failure

There has been a long-standing concern over the cardiovascular effects of tricyclic antidepressants, particularly in patients with preexisiting cardiac disease. Recent studies have demonstrated that imipramine causes no deleterious effect on ejection fraction as determined by radionuclide angiography in patients with impaired left ventricular function (LVF). However, the high rate of severe orthostatic hypotension induced by imipramine makes use of the drug problematic in these patients. Bupropion is a new antidepressant of the aminoketone class which is structurally unrelated to the tricyclics and which is relatively free of cardiac side effects in healthy depressed patients. We compared imipramine and bupropion in 10 depressed patients with impaired LVF in a random, double-blind crossover study. Neither imipramine nor bupropion adversely affected ejection fraction or other indices of LVF. However, as previously reported, severe orthostatic hypotension requiring discontinuation of drug developed in 50% of patients on imipramine. This difficulty did not occur with bupropion. From a cardiac perspective, bupropion may offer a safe alternative to imipramine in depressed patients with congestive heart failure.

Cardiovascular effects of doxepin in cardiac patients with ventricular arrhythmias

The effect of doxepin on ventricular arrhythmias, the ECG, and left ventricular function was evaluated in 10 cardiac patients with symptoms with frequent ventricular premature depolarizations in a dose-ranging protocol. Four patients (40%) had greater than or equal to 80% ventricular premature depolarization suppression; four of eight with pairs and four of six with ventricular tachycardia had greater than or equal to 90% suppression. The mean maximal doxepin dose was 115 +/- 41 mg/day; mean nadir total doxepin concentration was 61 +/- 48 ng/ml and mean nadir total desmethyldoxepin concentration was 51 +/- 42 ng/ml. Doxepin increased the heart rate and the PR, QRS, and QTc intervals of the surface ECG (P not significant). There was no significant change in resting mean left ventricular ejection fraction with doxepin: 41% +/- 15% vs. 43% +/- 19% (P not significant). Complaints of sedation (eight patients) limited dose ranging and tolerance to the drug. Although doxepin suppressed ventricular premature depolarizations in four patients, marked sedation limits its usefulness for primary treatment of arrhythmias in this population.

Antiarrhythmic effect of lorcainide in patients taking digoxin

To assess the antiarrhythmic effect of lorcainide and determine whether there is a pharmacokinetic interaction between lorcainide and digoxin, 12 patients with frequent premature ventricular depolarizations (PVDs) who were taking digoxin were treated with lorcainide. During a placebo period, serum digoxin concentration was measured for three days; plasma lorcainide concentration, a 12-lead electrocardiogram (ECG), and a 24-hour continuous ECG were measured on the day before the patients began lorcainide and repeated on days 3, 7, and 14 of treatment. Lorcainide was given 100 mg bid or 100 mg tid. Lorcainide did not suppress group mean PVDs per hour, pairs, or ventricular tachycardia. Only four patients (33%) responded with greater than or equal to 80% suppression of PVDs. Mean ejection fraction for responders was 46 +/- 6%, and for nonresponders it was 28 +/- 9% (P less than .01). There was no significant pharmacokinetic interaction between lorcainide and digoxin. Mean digoxin concentration did not change after lorcainide administration; two patients had greater than or equal to 50% increase in serum digoxin concentration. Patients with heart failure or reduced ejection fraction define a subset who have unpredictable effects from lorcainide, including a reduced antiarrhythmic effect.

Tricyclic antidepressants in depressed patients with cardiac conduction disease

The observation that fatalities from tricyclic antidepressant (TCA) overdose are associated with heart block and/or arrhythmias has led to concern about the cardiovascular effects of TCAs. Contrary to expectations, studies have shown TCAs to be relatively safe in patients without heart disease. However, it is unclear whether these drugs are also safe in patients with heart disease. This prospective study compared the risk of cardiovascular complication at therapeutic plasma concentrations of TCAs in 196 depressed patients, 155 with normal electrocardiograms and 41 with either prolonged PR interval and/or bundle-branch block. The prevalence of second-degree atrioventricular block was significantly greater in patients with preexisting bundle-branch block (9%) than in patients with normal electrocardiograms (0.7%). Orthostatic hypotension occurred significantly more frequently with imipramine than with nortriptyline, and in patients with heart disease.

Nortriptyline in depressed patients with left ventricular impairment

Previous studies of the effect of tricyclic antidepressants on left ventricular function in depressed patients with moderate to severe ventricular impairment have focused primarily on imipramine hydrochloride. In a prior study, we found that although imipramine had no effect on ejection fraction as measured by first-pass radionuclide angiography, the treatment could not be tolerated by 50% of the patients because of intolerable drug-induced orthostatic hypotension. Nortriptyline hydrochloride is an effective antidepressant that, in depressed patients without heart disease, causes significantly less orthostatic hypotension than imipramine. To see if this advantage could be safely extended to patients with congestive failure, we measured the effect of nortriptyline on ejection fraction and blood pressure in 21 depressed patients with left ventricular impairment. Ejection fraction was unchanged by nortriptyline treatment, and orthostatic hypotension developed in only one (5%) of 21 patients. Nortriptyline emerges as a relatively safe treatment for depression in patients with left ventricular impairment.

The antiarrhythmic effect of nortriptyline in cardiac patients with ventricular premature depolarizations

The effect of nortriptyline against ventricular arrhythmias was determined in 16 cardiac patients with 30 or more ventricular premature depolarizations per hour. Nortriptyline was administered orally, 0.5 mg/kg body weight per day, and increased by 0.5 mg/kg per day every third day until ventricular premature depolarizations were suppressed (greater than or equal to 80%), adverse effects occurred or a total daily dose of 3.5 mg/kg per day was given. Each patient had daily 24 hour continuous electrocardiograms, 12 lead standard electrocardiograms and physical examination; blood pressure was measured in the supine and standing position four times a day. Each patient also had radionuclide angiography at rest to measure ejection fraction before and at the effective or maximal dose. Thirteen patients (81%) had an antiarrhythmic response and 11 met the study criterion of at least 80% improvement. Doses ranged from 50 to 200 mg/day (mean 111 +/- 45), steady state plasma concentration ranged from 46 to 410 ng/ml (mean 153 +/- 96) and half-life of elimination of nortriptyline was 4 to 22 hours (mean 13 +/- 4). Administration of nortriptyline did not depress mean ejection fraction (before 42 +/- 12%, after 41 +/- 12%); it was associated with an orthostatic decrease in systolic blood pressure (mean -13 +/- 13 mm Hg). Nortriptyline is an effective antiarrhythmic agent which may be given twice a day even in patients with impaired ventricular function.

Time course of alpha-1-acid glycoprotein and its relation to myocardial enzymes after acute myocardial infarction

The acute phase reactant, alpha-1-acid glycoprotein, binds to a number of basic antiarrhythmic drugs, including lidocaine, quinidine, propranolol, imipramine and disopyramide. Binding to alpha-1-acid glycoprotein accounts for a decrease in free drug fraction and may alter the expected concentration: response relation of drugs particularly when there are unpredictably large or rapid changes in alpha-1-acid glycoprotein. To determine the time course and magnitude of alpha-1-acid glycoprotein for 1 month after acute myocardial infarction (AMI), blood samples were collected from 27 patients, 14 with AMI and 13 with a chest pain syndrome but no AMI. Patients with AMI had a significant increase in alpha-1-acid glycoprotein after 72 hours (mean 153 +/- 35 mg/dl) (p less than 0.05), and the maximum was observed on day 7 (mean 165 +/- 53 mg/dl) (p less than 0.05), returning to baseline by 28 days. There was no significant change in alpha-1-acid glycoprotein in patients with chest pain but no AMI. Regression analysis showed a significant relation between creatine kinase (p less than 0.005) and lactic dehydrogenase (p less than 0.001) vs alpha-1-acid glycoprotein indicating alpha-1-acid glycoprotein concentration is high in patients with large AMI. Changes in binding resulting from alpha-1-acid glycoprotein during AMI could account for misinterpretation of total drug concentration and response to antiarrhythmic drugs acutely, during convalescence and at discharge.

Effect of imipramine and nortriptyline on left ventricular function and blood pressure in patients treated for arrhythmias

The effect of imipramine or nortriptyline on left ventricular function and orthostatic blood pressure was evaluated in 20 nondepressed cardiac patients treated for ventricular premature depolarizations (VPDs). Drug was administered by mouth and dose ranging used, 1 mg/kg/day (imipramine) or 0.5 mg/kg/day (nortriptyline), was increased after four doses (imipramine) or six doses (nortriptyline) until greater than 80% suppression of VPDs or adverse effects occurred or until a maximum dose of 5 mg/kg/day (imipramine) or 3.5 mg/kg/day (nortriptyline) was given. Fourteen (70%) had greater than 80% VPD suppression, five had less than 80% improvement (range 25% to 77%), and one had a VPD frequency increase of 6%. Mean daily imipramine dose was 210 +/- 103 mg and mean nortriptyline dose was 100 +/- 29 mg. Neither drug significantly changed mean ejection fraction or peak systolic pressure end-systolic volume ratio by radionuclide angiogram. Both reduced standing systolic blood pressure: mean change after imipramine was 26 mm Hg (NS), and after nortriptyline, 14 mm Hg (p less than 0.05). Drug was discontinued in two patients because of symptomatic orthostatic blood pressure change greater than 30 mm Hg. There was not a significant relationship between dose, drug concentration, or functional class and orthostatic change in systolic blood pressure but there was for age (p less than 0.05). These observations suggest that even cardiac patients with impaired systolic function may take imipramine or nortriptyline for VPDs; however, frequent blood pressure measurement is advised, particularly in older patients.

Procainamide: clinical pharmacology and efficacy against ventricular arrhythmias

Procainamide (PA) has been a mainstay of treatment against acute and chronic supraventricular and ventricular arrhythmias for more than 30 years. PA's clinical pharmacology has been studied extensively and its bioavailability (75-95%); volume of distribution (1.5-2.5 liters per kg), plasma protein-binding (15-25%), half-time for elimination (3-7 hours), and metabolism are known. PA's efficacy against acute ventricular arrhythmias and chronic stable VPDs is associated with plasma drug concentrations of 4 to 10 micrograms per ml; but much higher plasma concentrations may be required against sustained ventricular arrhythmias. From 30 to 60% of a PA dose is excreted as the metabolite, N-acetylprocainamide (NAPA), and PA's metabolism is determined genetically (fast or slow acetylation phenotype). Studies in patients with VPDs indicate that NAPA is also antiarrhythmic, although the contribution of NAPA to the antiarrhythmic effect after PA is not known. Studies in patients with the systemic lupus-like syndrome from PA show that NAPA is not associated with this. Investigations comparing efficacy and adverse effects of PA with those of new antiarrhythmic agents available for clinical trials are indicated in the future.

Imipramine binding to alpha-1-acid glycoprotein in normal subjects and cardiac patients

The relationship between binding ratio of imipramine and plasma alpha 1-acid glycoprotein (AAG) was determined in normal subjects, patients with chest pain syndrome, and patients after myocardial infarction. Binding ratio of imipramine was determined by equilibrium dialysis and plasma AAG concentration was determined by radial immunodiffusion. Plasma AAG concentrations ranged from 56 to 80 mg/dl (mean = 65 +/- 9 mg/dl) in 12 normal subjects, from 86 to 228 mg/dl (mean = 125 +/- 37 mg/dl) in 12 patients with chest pain syndrome, and from 78 to 350 mg/dl (mean = 181 +/- 69 mg/dl) in 12 patients after myocardial infarction. Plasma AAG concentrations in the three patient groups differed. Binding ratio ranged from 5.6 to 19.8 (mean = 12 +/- 3.5). Binding ratio of imipramine significantly correlated with plasma AAG concentration, but not with plasma albumin. In addition, binding ratio of imipramine and pure AAG was significantly related, indicating AAG is an important determinant for imipramine binding. If plasma AAG concentration increases or changes rapidly, plasma drug concentration and drug effect may be unpredictable. Under these circumstances an estimate of free drug fraction may be clinically helpful and can be estimated from the formula. y = 7.95 + 0.03 X AAG.

The use of imipramine in depressed patients with congestive heart failure

Previous studies of left ventricular performance (LVP) in depressed patients receiving tricyclic antidepressants have been performed on patients without severe heart disease. This study reports the effect of imipramine hydrochloride on LVP, assessed by radionuclide angiography, in a group of depressed patients with notable preexisting left ventricular dysfunction. Ejection fraction was measured at rest by first-pass radionuclide angiography before and after treatment with imipramine. Ejection fraction was unchanged during treatment, but seven of 15 patients experienced orthostatic hypotension of such severity that administration of the drug had to be discontinued. Plasma concentrations of the drug were essentially twice those usually seen. It is important to appreciate that although imipramine does not further impair resting LVP, this does not mean it is without risk. The physician must watch carefully for orthostatic hypotension when using imipramine in depressed patients with impaired LVP.

Antiarrhythmic plasma-concentration range of imipramine against ventricular premature depolarizations

The antiarrhythmic plasma-concentration range of imipramine with desmethylimipramine was determined in 15 cardiac patients with ventricular arrhythmias. When more than 80% efficacy was reached, subjects' plasma concentrations of imipramine and desmethylimipramine were determined by gas chromatography. The imipramine dose required for suppression of ventricular premature depolarizations (VPDs) ranged from 50 to 400 mg a day (1.6 to 3.9 mg/kg/day). Peak plasma imipramine concentration was reached at 2.5 +/- 0.92 hr and peak plasma desmethylimipramine concentration at 4.1 +/- 2.8 hr after imipramine. At 80%, VPD suppression, mean steady-state plasma concentration of imipramine with desmethylimipramine ranged from 74 to 385 ng/ml. The ratio of plasma imipramine to desmethylimipramine ranged from 0.5 to 5.5 (median = 1.3). The elimination t1/2 for the parent compound, imipramine, ranged from 4 to 14.4 hr. Imipramine is an effective antiarrhythmic drug with sustained duration of action, although its elimination t1/2 is relatively short.

Desmethylimipramine and imipramine on left ventricular function and the ECG: a randomized crossover design

Sixteen severely depressed patients participated in a double-blind randomized, crossover study to compare the effects of desmethylimipramine and imipramine on left ventricular function and the electrocardiogram. Following a drug-free week, patients had 3 weeks of therapy each with desmethylimipramine and imipramine. During each treatment period systolic time intervals, echocardiograms and high-fidelity electrocardiograms were recorded. There was no difference between desmethylimipramine and imipramine on (1) systolic time intervals, (2) shortening fraction or mean velocity of circumferential shortening, or (3) the electrocardiogram. There was a difference between the drug-free period and desmethylimipramine or imipramine on the PEPc (P less than 0.05) and the PEP/LVET ratio (P less than 0.05); on the R-R (P less than 0.05), PR (P less than 0.05), QRS (P less than 0.05), and QTc (P less than 0.05) intervals; but no difference on the LVETc or shortening fraction or the mean velocity of circumferential shortening. Drugs such as desmethylimipramine and imipramine which prolong intraventricular conduction can probably be expected to prolong the PEP and PEP/LVET. For this reason systolic time intervals have limitations in assessing myocardial function and the echocardiogram more reliably estimates myocardial performance in patients receiving tricyclic antidepressants.

Antiarrhythmic effect of imipramine hydrochloride in patients with ventricular premature complexes without psychological depression

A study was performed in cardiac patients without psychological depression to determine (1) the antiarrhythmic efficacy of imipramine, (2) its half-life of elimination and duration of action, and (3) the frequency of adverse effects. Twenty-two patients with 30 or more ventricular premature complexes/hour entered the protocol. A drug-free and a placebo day were followed by dosing with imipramine, 1 mg/kg per day, given in two divided doses. The dose was increased by 1 mg/kg per day every other day until ventricular premature complexes were suppressed by at least 80 percent, adverse drug effects were encountered or a total daily dose of 5 mg/kg per day was given. Each day a 24 hour continuous electrocardiogram was recorded to determine the frequency of ventricular premature complexes and heart rate. During the acute dose-ranging period, 18 patients (82 percent) had an antiarrhythmic effect from imipramine. Two patients received 5 mg/kg per day without any decrease in the frequency of ventricular premature complexes. The half-life of elimination of imipramine (parent compound) was 8.8 +/- 3.72 hours but its duration of action was much longer. Four patients (18 percent) had treatment discontinued because of troublesome adverse effects during a follow-up period of 19 +/- 8.8 months. It is concluded that imipramine is a potent antiarrhythmic drug with a long duration of action and relatively few major adverse effects.

Factors related to orthostatic hypotension associated with tricyclic antidepressants

A group of 45 depressed patients treated with imipramine hydrochloride were examined in an attempt to identify factors that might influence the risk of developing orthostatic hypotension. Although the literature suggests that age and/or heart disease influences the occurrence of orthostatic hypotension, these conclusions are controversial. To pursue this issue, a sample of older depressed patients, many with severe cardiovascular disease, was chosen. The incidence of orthostatic hypotension rose dramatically among those with severe heart disease. There was a significant association between symptomatic orthostatic hypotension and cardiac medication (p less than .01), and trends between orthostatic hypotension and both ejection fraction (p = .11) and baseline forearm resistance (p = .16). The sample is too small to permit determination of the relative independent importance of these variables or the contribution of specific cardiovascular drugs among these sicker cardiac patients.

Efficacy, plasma concentrations and adverse effects of a new sustained release procainamide preparation

To assess the efficacy, plasma drug concentrations and adverse effects of a new sustained release preparation of procainamide, 33 patients with heart disease were studied in an acute dose-ranging protocol and a chronic treatment protocol. Patients initially received a daily dose of 3 g of sustained release procainamide; this dose was increased by 1.5 g daily until ventricular premature depolarizations were suppressed by 75 percent or more, adverse drug effects occurred or a total daily dose of 7.5 g of sustained-release procainamide was reached. Twenty-five patients (76 percent) had at least a 75 percent reduction (range 75 to 100percent [mean +/- standard deviation 91 +/- 8.2]) in ventricular permature depolarization frequency at a dosage of 4.8 +/- 1.46 g/day (range 3.0 to 7.5). Despite the 8 hour dosing interval, the variation between maximal and minimal plasma procainamide and N-acetylprocainamide concentrations under steady state conditions was very small. Mean maximal procainamide and N-acetylprocainamide plasma concentrations were 10.4 +/- 6.02 and 12.0 +/- 7.40 micrograms/ml, respectively. The respective mean minimal concentrations were 6.8 +/- 4.50 and 8.7 +/- 5.99 micrograms/ml. In nine patients (27 percent) treatment with sustained release procainamide resulted in conversion of the antinuclear antibody test from negative to positive. Adverse drug effects occurred in 17 (52 percent) of the subjects. In general, adverse effects were minor and abated within 24 hours after administration of the drug was stopped. One patient had the procainamide-induced systemic lupus erythematosus-like syndrome.

Combined mexiletine and propranolol treatment of refractory ventricular tachycardia

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The effect of quinidine and other oral antiarrhythmic drugs on serum digoxin. A prospective study

We compared the effects of quinidine and three alternate antiarrhythmic drugs on serum digoxin concentration in 63 patients before and during administration of quinidine, procainamide, disopyramide, or mexiletine. Quinidine increased digoxin concentration by at least 0.5 nmol/L in 21 of 22 patients: Mean serum digoxin rose from 1.2 nmol/L to 2.4 nmol/L (P less than 0.001). Procainamide, disopyramide, or mexiletine increased serum digoxin by 0.5 nmol/L in one of 41 patients. Anorexia, nausea, and vomiting develop soon after starting quinidine therapy in 10 of the 22 patients who received quinidine but in only five of the 41 patients who received procainamide, disopyramide, or mexiletine (P less than 0.01). Quinidine prolonged the PR intervals from 160 +/- 14 ms to 183 +/- 26 ms, but procainamide, disopyramide, and mexiletine did not change the PR interval (P less than 0.005). In digitalized patients, quinidine increases serum digoxin concentration, increases digoxin's effect on atrioventricular conduction, and produces more adverse gastrointestinal effects than procainamide, disopyramide, or mexiletine.

The electrocardiographic and antiarrhythmic effects of imipramine hydrochloride at therapeutic plasma concentrations

The electrocardiographic effects of imipramine hydrochloride at therapeutic plasma concentrations were determined in 44 depressed patients during a 6-week clinical outcome study of depression. During each week of the protocol, i.e., 2 weeks of control and 4 weeks of drug treatment, a standard 12-lead ECG, high-speed, high-fidelity ECG tracings, and a 24-hour continuous ECG recording were obtained. PR, QRS, and QTc intervals, T-wave amplitude, heart rate and frequency of ventricular premature depolarizations (VPDs) were measured. The plasma concentration of imipramine and desmethylimipramine was measured three times a week. Imipramine prolonged the PR (p less than 0.001), QRS (p less than 0.001) and QTc (p less than 0.001) intervals, increased the heart rate (p less than 0.001) and lowered T-wave amplitude (p less than 0.05) during the 4 weeks of treatment. No patient developed high-grade atrioventricular block or severe intraventricular conduction abnormalities. In addition, imipramine had a potent antiarrhythmic action in patients who were recovering from depression. Ten of 11 patients who had more than 10 VPDs/hour had 90% or greater arrhythmia suppression during antidepressant treatment with imipramine at plasma concentrations ranging from 100--302 ng/ml.

Electrophysiologic evaluation of sinus node function in patients with sinus node dysfunction

Twenty patients of mean age 66.2 years, with suspected sinus node dysfunction, underwent extensive electrophysiologic study. Sinus bradycardia (18), sinus pauses (3), and sinoatrial block (1) were identified in their ECGs prior to study. Also 11 patients had some abnormality of atrioventricular nodal and/or intraventricular conduction prior to study. At the time of electrophysiological study, 10/20 patients (50%) had a mean cycle length exceeding 1000 msec, and mean P-V interval exceeded 210 msec in 7/20 (35%). The estimated "sinoatrial conduction time" exceeded 215 msec in 6/16 (38%) patients. The maximum first escape cycle following pacing at six different rates exceeded a value equal 1.3 X the mean value of the control cycle length + 101 msec (slope of regression line + Y intercept + 1 SD) in 13/9 (68%) patients. Nineteen patients received 1 mg atropine intravenously and mean cycle length decreased by 19%, from 891 +/- 175.8 msec to 718 +/- 182.9 msec. Graded infusion of isoproterenol was employed in 19 patients; four patients required an infusion rate greater than 28.3 ng/kg/min to produce a 20% decrease in spontaneous sinus cycle length. These data would indicate that a variety of interventions are required to characterize the disturbance of sinus node automaticiy and sinoatrial conduction in patients with sinus node dysfunction.

Effect of procainamide and lidocaine on total electrical systole of ventricular premature depolarizations

The effect of lidocaine and procainamide on the electrocardiogram of a patient with coupled ventricular premature depolarizations was observed after continuous electrocardiographic monitoring during a control period and drug therapy. First lidocaine, 100 mug/kg/min, and 3 1/2 hours later procainamide, 200 mug/kg/min, were infused until the arrhythmia was completely suppressed. In each drug study, blood samples were taken every 5 minutes for determining plasma drug concentration. In addition to important differences between the two drugs on the standard electrocardiographic intervals, a new electrocardiographic phenomenon was recognized: a change in the total electrical systole of the ventricular premature depolarization (ventricular premature depolarization-Q-T interval). These observations are discussed and related to the electrophysiologic properties reported for each of these agents.

"Paradoxical" prolongation of sinus nodal recovery time after atropine in the sick sinus syndrome

A case of symptomatic sick sinus syndrome is presented with confirmation of sinus nodal dysfunction established by functional testing. The validity of such provocative testing and the criteria for abnormality are discussed. A newly recognized, seemingly "paradoxical" and potentially detrimental effect of atropine noted in this patient is examined. Despite an increase in sinus rate and an improvement in sinoatrial conduction time after administration of atropine, a markedly prolonged sinus recovery time after rapid atrial pacing occurred, and atrial quiescence for more than 10 seconds was seen. Possible electrophysiologic mechanisms for this phenomenon, such as decreased atriosinus entrance block, concealed sinoatrial reentry or enhanced intranodal depolarization, are discussed and potential clinic correlates are made.

Procaine amide against re-entrant ventricular arrhythmias. Lengthening R-V intervals of coupled ventricular premature depolarization as an insight into the mechanism of action of procaine amide

Nine patients with coupled ventricular premature depolarizations (VPDs) were treated with intravenous procaine amide to abolish the arrhythmia. The effect of procaine amide on the electrocardiogram was carefully observed. Seven patients were treated with intermittent intravenous therapy-100 mg of procaine amide was injected every five minutes-and two were treated by constant intravenous infusion-200 µg/min/kg body weight; blood for plasma procaine amide concentration was obtained 4.5 to 5 min after each dose. As the cumulative dose of procaine amide increased, plasma drug concentration increased and the frequency of coupled VPDs progressively decreased. Moreover, in every patient an interesting electrocardiographic phenomenon was observed: as plasma drug concentration increased, the coupling interval progressively increased until the arrhythmia was completely abolished. A hypothesis for procaine amide's antiarrhythmic action is offered based on this new observation. This hypothesis suggests that procaine amide prolongs conduction in the depressed portion of a re-entrant pathway such that conduction is further delayed and block finally occurs, thereby terminating the arrhythmia.