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Biomedical subjects

H J Crijns

Publications and source records attributed to H J Crijns.

At least 19 recordsLinked to original sources
PubMed1992

Electropharmacologic effects and pharmacokinetics of almokalant, a new class III antiarrhythmic, in patients with healed or healing myocardial infarcts and complex ventricular arrhythmias.

The electropharmacologic effects and pharmacokinetics of almokalant, a new class III antiarrhythmic, were investigated in a randomized, placebo-controlled, double-blind study, and efficacy was evaluated. Ten post-myocardial infarction patients with complex ventricular arrhythmias were included and received, in randomized order on consecutive days, 4.5 mg (12.8 mumol) of almokalant or placebo intravenously over 10 minutes. One patient received infusion at a higher rate and developed self-terminating torsades de pointes. In the remaining 9 patients the corrected QT interval increased significantly: At the end of placebo infusion the corrected QT was 445 +/- 18 ms and after almokalant 548 +/- 53 ms (p = 0.0015). The signal-averaged electrocardiographic parameters did not change. The number of ventricular premature complexes decreased significantly during the first 15 minutes after almokalant infusion (p = 0.04). No additional proarrhythmic or other significant adverse events were noted. The almokalant plasma concentration showed a biphasic decrease with an elimination half-life of 2.4 +/- 0.1 hours. Almokalant was rapidly cleared from the body with a clearance of 11 +/- 1 ml/min/kg. When given with certain precautions almokalant appears safe and well-tolerated and may be antiarrhythmic by prolonging refractoriness.

Adult↗
PubMed1992

Low-dose amiodarone for maintenance of sinus rhythm after cardioversion of atrial fibrillation or flutter.

OBJECTIVE: To study efficacy and safety of low-dose amiodarone for maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation or flutter. DESIGN: Nonrandomized trial; mean duration of follow-up, 20.7 months. SETTING: Referral center; institutional practice; both hospitalized and ambulatory care. PATIENTS: Eighty-nine consecutive patients having chronic atrial fibrillation or flutter and eligible for cardioversion. Patients had failed previous treatment aimed at maintaining sinus rhythm. During follow-up one patient was withdrawn because of side effects; all patients were available for follow-up. INTERVENTION: Before cardioversion, patients received 600 mg of amiodarone daily during a 4-week loading period. After conversion, the daily maintenance dose was 204 +/- 66 mg (mean +/- SD). MAIN OUTCOME MEASURES: Arrhythmia recurrence and adverse effects causing drug discontinuation. RESULTS: During loading, 15 patients (16%) converted, and after electrical cardioconversion, 90% of all patients had sinus rhythm. Actuarially, 53% of these patients were still in sinus rhythm after 3 years. In patients with compromised left ventricular function, 93% maintained sinus rhythm after 6 months. One patient died due to congestive heart failure. Intolerable side effects occurred in one patient. No proarrhythmia was observed. Logistic regression analysis revealed that amiodarone was ineffective in patients with mitral stenosis or chronic arrhythmia. CONCLUSIONS: Low-dose amiodarone is effective for maintaining sinus rhythm in patients with difficult to treat chronic atrial fibrillation or flutter and is associated with a low incidence of serious side effects.

Amiodarone↗
PubMed1992

Triggered activity as arrhythmogenic mechanism after myocardial infarction: clinical and electrophysiologic study of one case.

In a woman with an old infarction and sustained ventricular tachycardia, tachycardias were only inducible after short-long RR sequences. After isoprenaline, tachycardias became incessant and all were preceded by short-long RR sequences. This strongly suggests that triggered activity plays a role in initiation of ventricular tachycardias in postinfarction patients.

Aged↗
PubMed1991

Electrophysiologic profile of ibopamine in patients with congestive heart failure and ventricular tachycardia and relation to its effects on hemodynamics and plasma catecholamines.

Programmed electrical stimulation was performed in 12 patients with moderate to severe congestive heart failure and ventricular tachycardia (VT) to study possible arrhythmogenic properties of ibopamine, a new orally active dopamine agonist. Ibopamine induced no significant changes in spontaneous cycle length, PR, QRS, QTc, AH or HV intervals, and also right ventricular effective refractory periods were unaffected (for paced cycle lengths of 600 and 430 ms, respectively, using 1 extrastimulus: 287 +/- 16 ms at baseline vs 283 +/- 27 ms after ibopamine and 270 +/- 23 ms during the control study vs 262 +/- 19 ms after ibopamine). In 6 of the 8 patients with coronary artery disease but in none of the 4 patients with dilated cardiomyopathy, sustained VT was induced before and after ibopamine. Proarrhythmia was present in 1 patient, who became inducible after ibopamine. However, 1 patient had sustained VT only at baseline but not after ibopamine. The number of extrastimuli required for VT induction was equal (2.7 +/- 0.2 vs 2.7 +/- 0.2). Holter monitoring showed no changes in ventricular premature complexes, ventricular couplets and runs of VT after 1 week of ibopamine therapy. The signal-averaged electrocardiogram was abnormal in 11 and showed late potentials in 5 patients, but no changes occurred after ibopamine. During hemodynamic evaluation, increases in cardiac (32%) and stroke volume (34%) indexes were seen after administration of 100 mg of ibopamine, accompanied by a decrease in vascular resistance and filling pressures. Plasma norepinephrine decreased significantly after ibopamine (p = 0.02) but plasma epinephrine was unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Serial antiarrhythmic drug treatment to maintain sinus rhythm after electrical cardioversion for chronic atrial fibrillation or atrial flutter.

The sequential use of different types of antiarrhythmic drugs may improve arrhythmia prognosis in chronic atrial fibrillation or flutter after successful electrical cardioversion. The rationale for serial treatment is that the arrhythmogenic mechanism may vary between patients, leading to different responses to 1 specific drug. To investigate this issue prospectively, 127 patients having chronic fibrillation or flutter exclusively, underwent serial drug treatment with flecainide (stage I) followed by sotalol or, if contraindicated, quinidine (stage II) and eventually amiodarone (stage III). Stages II and III were entered after electrical recardioversion for a recurrence during stages I or II, respectively. Calculated on an actuarial basis, the 2-year cumulative percentage of patients free of the arrhythmia increased from 31% after stage I to 63% at the end of serial treatment. To reach this result, a mean of 1.8 +/- 0.8 cardioversions per patient were needed, with 53 patients progressing to stage II and 34 to stage III. Sixteen patients stopped serial treatment prematurely and 15 patients were considered to have intractable atrial fibrillation at the end of stage III. Incidence of proarrhythmia was low. Multivariate analysis disclosed that an older age, in combination with a large number of previous episodes of arrhythmia, a long previous duration of arrhythmia and presence of mitral valve disease, were predictive for medical refractoriness during serial treatment. It is concluded that serial treatment may improve arrhythmia prognosis in atrial fibrillation or flutter, with an acceptable incidence of proarrhythmic events.

Actuarial Analysis↗
PubMed1991

Prediction of uneventful cardioversion and maintenance of sinus rhythm from direct-current electrical cardioversion of chronic atrial fibrillation and flutter.

The present study was undertaken to reassess prospectively the immediate and long-term results of direct-current electrical cardioversion in chronic atrial fibrillation or atrial flutter, and to determine factors predicting clinical outcome of the arrhythmia after direct-current cardioversion. Two-hundred forty-six patients underwent direct-current electrical cardioversion and were followed during a mean of 260 days. Multivariate analysis was used to identify factors predicting short- and long-term arrhythmia outcome. Cardioversion was achieved in 70% of patients with atrial fibrillation and in 96% of patients with atrial flutter. Stepwise logistic regression analysis revealed that arrhythmia duration (p less than 0.001), type of arrhythmia (fibrillation vs flutter, p less than 0.02) and age (p less than 0.05) independently influenced conversion rate. On an actuarial basis, 42 and 36% of patients remained in sinus rhythm during 1 and 2 years, respectively. Multivariate regression analysis revealed that the type of arrhythmia (p = 0.0008), low precardioversion functional class (p = 0.002) and the presence of nonrheumatic mitral valve disease (p = 0.03) independently increased the length of the arrhythmia-free episode. Rheumatic heart disease shortened this period (p = 0.03). In conclusion, patients having a high probability of conversion together with a prolonged post-shock arrhythmia-free episode can be identified. This may improve the cost-benefit ratio of cardioversion.

Adult↗
PubMed1991

Incidence and clinical significance of ST segment elevation after electrical cardioversion of atrial fibrillation and atrial flutter.

To study the incidence and clinical significance of postshock ST segment elevations, we recorded 12-lead ECGs immediately after transthoracic direct-current electrical cardioversion in 146 patients with atrial fibrillation or flutter. Among 23 patients (19%), acute ST segment elevations amounted to 1.4 +/- 0.8 mV (mean +/- SD) and occurred after 243 +/- 114 joules (cumulative dose) in the precordial leads only in 14, concomitantly in precordial and inferior leads in two, and in the precordial and anterolateral leads in seven. They normalized within 1.5 +/- 0.8 minutes. Occurrence of ST segment elevation was related to previous pericardiotomy (p less than 0.00001) and age (p = 0.01). Estimation of myocardial enzyme release did not show evidence of myocardial damage. Patients with ST segment elevations had a lower conversion rate (48% versus 76%, p = 0.005). Long-term maintenance of sinus rhythm was also diminished (35% versus 59%, p = 0.03). Results of this study show that postcardioversion ST segment elevation occurs predominantly in postpericardiotomy patients and may be associated with an unfavorable arrhythmia prognosis.

Age Factors↗
PubMed1991

The oral dopamine agonist, ibopamine, in normal man: effects on rhythm, heart rate, blood pressure and catecholamines.

To evaluate the effects of the oral aselective dopamine congener ibopamine, heart rate, blood pressure, cardiac rhythm, electrocardiographic (ECG) parameters and plasma catecholamines were studied in ten healthy subjects on three occasions: without medication, after 100 mg oral ibopamine and after combined treatment of ibopamine and the dopamine antagonist metoclopramide. Ibopamine was well tolerated by all subjects. No significant changes in heart rate or blood pressure were seen during either ibopamine alone or during concomitant metoclopramide administration. In addition, there were no differences in PR-, QRS- and QTc- intervals on the ECG and plasma norepinephrine, epinephrine and dopamine levels were unchanged. None of the ten volunteers showed proarrhythmia from ibopamine. However, in one subject, episodes of accelerated idioventricular rhythm were observed after ibopamine, which were asymptomatic and did not exceed a rate of 51 beats/minute. During concomitant metoclopramide infusion, ibopamine did not induce accelerated idioventricular rhythm. In conclusion, in healthy subjects ibopamine appears to be a safe drug and causes neither proarrhythmia, nor changes in heart rate, blood pressure, ECG-parameters, or plasma catecholamines.

Administration, Oral↗
PubMed1990

Efficacy and safety of ibopamine in congestive heart failure.

1. Ibopamine is a new orally active inodilator, which is developed for the treatment of congestive heart failure (CHF). We treated 13 patients with moderate to severe CHF already on maximal conventional medication with ibopamine and studied its effects on haemodynamic parameters, exercise capacity, plasma norepinephrine (NE) and ventricular arrhythmias on ambulatory ECG monitoring. 2. Both cardiac and stroke volume index increased significantly after ibopamine (33% and 35% resp.). These changes were accompanied by a fall in systemic vascular resistance without changes in heart rate or blood pressure. During cardiopulmonary exercise testing, both maximal oxygen consumption and exercise time increased. Plasma NE levels were not significantly changed after ibopamine. Using the Morganroth criteria for proarrhythmia on ambulatory ECG monitoring, two patients showed proarrhythmia from ibopamine, which was not clinically relevant, but four patients had a decrease in ventricular arrhythmias. 3. This study suggests that ibopamine elicits favourable effects on haemodynamics and exercise tolerance in patients with CHF. During ibopamine treatment, there appears to be no increase in ventricular arrhythmias.

Adult↗
PubMed1990

Range of atrioventricular conduction disturbances in Lyme borreliosis: a report of four cases and review of other published reports.

Four patients with Lyme borreliosis had atrioventricular conduction disturbances. All four were positive for specific antibodies against Borrelia burgdorferi measured by indirect immunofluorescence tests. Biopsy specimens, which were obtained in three patients, showed band-like infiltrates of plasma cells and lymphocytes in the endocardium. There was diffuse infiltration of the interstitium of the myocardium by lymphocytes, plasma cells, and macrophages. In two patients single fibre necrosis was seen in the myocardium. Biopsy specimens of the heart showed spirochetes in all three patients and serial sections stained by the Bosma-Steiner technique showed that they resembled Borrelia burgdorferi. At follow up one patient had persistent complete atrioventricular block, despite treatment with antibiotics and corticosteroid, and a permanent pacemaker was implanted.

Adult↗
PubMed1990

Flecainide: long-term effects in patients with sustained ventricular tachycardia or ventricular fibrillation.

Efficacy of flecainide was investigated in 50 patients with sustained ventricular tachycardia (n = 38) or ventricular fibrillation (n = 12) during a 4-week in-hospital and 1-year follow-up period. Furthermore, the predictive value of programmed electrical stimulation, Holter monitoring, and exercise testing on outcome of long-term treatment was studied. Etiology of the tachyarrhythmia was coronary artery disease in 37 patients and other etiologies in 13 patients. The success rate of flecainide after 1 year, based on intention to treat, was 54%. The success rate during the in-hospital phase was 84% (in six patients flecainide was discontinued because of tachyarrhythmia and in two because of side effects). Calculated after 4 weeks hospitalization, the success rate was 78% for patients with tachyarrhythmias based on coronary artery disease and 55% for patients with tachyarrhythmias based on other etiologies (11 patients showed recurrences and two patients severe side effects). Patients with tachyarrhythmias based on coronary artery disease showed a lower ejection fraction and earlier recurrence than patients with arrhythmias based on other etiologies. Proarrhythmic effects developed in six patients (12%). Electrophysiological evaluation was performed in 28 patients at baseline and after intravenous flecainide. Negative predictive value of the electrophysiological evaluation after intravenous flecainide for patients with inducible tachyarrhythmias at baseline (n = 21) was 40%. For Holter monitoring (n = 24) this value was 86%. Non-ischemia-related induction of tachycardia by exercise was present in two of 30 patients on flecainide; both patients showed recurrence of the tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Efficacy and safety of flecainide acetate in the maintenance of sinus rhythm after electrical cardioversion of chronic atrial fibrillation or atrial flutter.

The efficacy and safety of flecainide were studied in the maintenance of sinus rhythm after electrical cardioversion for chronic atrial fibrillation or atrial flutter. Eighty-one patients were randomized to flecainide treatment or no treatment. Baseline characteristics of both groups were comparable. Compared to previous studies, patients could be classified as difficult-to-treat patients. Multiple regression analysis showed New York Heart Association class I for exercise tolerance (p = 0.0004) and flecainide treatment (p = 0.01) to be the main factors increasing the arrhythmia-free episode. However, Mantel-Cox lifetable analysis did not reveal significant differences between arrhythmia-free survival curves of both treatment groups. In the flecainide-treated group, 9% of patients experienced side effects, mostly related to negative dromotropic effects. The incidence of ventricular proarrhythmia in this group of patients was low. Thus, flecainide may be effective in postponing arrhythmia recurrence, even in difficult-to-treat patients. Caution should be excercised in treating patients with underlying conduction disturbances, sick sinus syndrome or characteristics favoring development of ventricular proarrhythmia.

Adolescent↗
PubMed1989

Cardiac electrophysiologic properties of intravenous isradipine in patients with sick sinus syndrome.

Isradipine is a new dihydrophyridine calcium antagonist with powerful vasodilating properties. Although therapeutic concentrations do not affect myocardial contractility in vivo, in vitro studies have demonstrated a negative chronotropic action with only minor dromotropic influence. In humans with normal sinus and atrioventricular node function, even in the presence of beta-blockade, such a negative chronotropic effect could not be proved. No data are available on the effects of isradipine on a compromised sinus node. Therefore, the effect of intravenous isradipine at 0.3 microgram/kg/minute for 30 minutes was studied in seven patients with the clinical signs of a sick sinus syndrome. Mean arterial blood pressure decreased from 126 +/- 21 to 113 +/- 15 mm Hg (p less than 0.05). Spontaneous sinus cycle length decreased from 969 +/- 22 to 843 +/- 161 msec (p less than 0.05). Changes in sinoatrial conduction time, sinus node recovery time, and corrected sinus node recovery time were not significant. Changes in atrioventricular node function, as reflected by the atrioventricular node functional refractory period, the atrial-His interval, the His-ventricle interval, and Wenckebach point were not significant. Also, effective refractory periods of atrium and ventricle, and QRS duration changed but not significantly. The QT interval decreased (419 +/- 45 to 405 +/- 44 msec; p less than 0.05), and there was a slight (not significant) increase of QTc interval (429 +/- 41 to 443 +/- 37 msec; not significant). It is concluded that isradipine in hemodynamically effective doses has no depressant effect on sinus and atrioventricular node function in patients with sick sinus syndrome.

Adult↗
PubMed1989

Flecainide acetate in the treatment of supraventricular tachycardias: value of programmed electrical stimulation for long-term prognosis.

Twenty patients with recurrent symptomatic supraventricular tachycardia were studied to estimate the efficacy of flecainide in the long-term treatment of these arrhythmias and to evaluate the prognostic value of programmed electrophysiologic stimulation. All patients had their arrhythmia inducible at baseline evaluation. Nine patients had a Wolff-Parkinson-White (WPW) syndrome, five had a concealed bypass tract, and two had dual atrioventricular (AV) nodal pathways. In the remaining patients there was an intraatrial reentry circuit. Previous medication was no to five antiarrhythmic drugs (mean 2.4 drugs). At baseline, a circus movement tachycardia was induced in 12, AV nodal tachycardia was induced in two, atrial tachycardia was induced in three, atrial fibrillation was induced in five, and a flutter was induced in two patients. After flecainide, 2 mg/kg intravenously in 10 minutes, six patients no longer had their arrhythmia inducible. In the WPW patients, atrial fibrillation was no more inducible. In 65% of the patients there was no recurrence during a follow-up period of 11 +/- 10 months. None of the six patients who no longer had their arrhythmia inducible had a recurrence of the tachycardia over a period of up to 3 years. Seven of the other 14 patients (who still had their arrhythmia inducible) had a recurrence of the tachycardia. Positive and negative predictive values are 50% and 100%, respectively. We conclude that flecainide prevents recurrences of supraventricular tachycardias in 65% of patients with inducible supraventricular tachycardias during a mean follow-up of 11 months. Programmed electrical stimulation has a high negative predictive value in this setting. Flecainide is especially effective in preventing atrial fibrillation in patients with WPW syndrome.

Adult↗
PubMed1989

Demonstration of spirochetes in cardiac biopsies of patients with Lyme disease.

Cardiac involvement occurring early in Borrelia burgdorferi infection is a clinical manifestation of human Lyme disease. Therefore, two patients with acute complete atrioventricular heart blocks and unexplained recurrent dizziness were studied. Both patients had significantly elevated serum titers of IgM and IgG antibodies to B. burgdorferi. Right ventricular subendocardial biopsies showed dense infiltrates consisting of lymphocytes and plasma cells. Silver staining revealed spirochetes characteristic of B. burgdorferi near and in the infiltrates, between the muscle fibers, and in the endocardium. One patient responded to penicillin; the other did not, necessitating installation of a pacemaker. Thus, permanent heart damage may result from cardiac involvement in Lyme disease.

Adult↗