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Biomedical subjects

T Meinertz

Publications and source records attributed to T Meinertz.

At least 217 records · Page 12Linked to original sources
PubMed1991

Time course and interrelation of reperfusion-induced ST changes and ventricular arrhythmias in acute myocardial infarction.

With the increasing use of thrombolytic therapy, the presence and time course of reperfusion-induced ventricular arrhythmias and ST-segment changes have become of particular interest. Technical improvements in bipolar Holter monitoring offer the opportunity to record both parameters continuously and simultaneously. Time course and interaction of both parameters in dependence on the onset of thrombolysis and time of reperfusion were investigated in 30 patients with acute myocardial infarction. Reperfusion was achieved in 20 patients after 49 +/- 23 minutes and in another 2 patients after 120 minutes (73%, group A). Vascular occlusion persisted in 8 patients for greater than 24 hours (group B). Sudden ST-segment changes (greater than 0.2 mV/15 min) in the bipolar leads indicated reperfusion in 7 of 22 patients (32%). Idioventricular rhythms, most frequent in reperfused patients (group A: 18 of 22 patients, mean 121 beats/hour), were unspecific reperfusion markers (group B: 5 of 8 patients, 1 beat/hour) unless frequent (p less than 0.05) or longer lasting, repetitive (p less than 0.01) episodes were considered. Premature ventricular beats and couplets (p less than 0.05) were also most frequent in group A (peak frequency 3 to 5 hours after thrombolysis). Ventricular tachycardia observed in 21 of 22 patients (95%) in group A and in 3 of 8 (38%) in group B (p less than 0.01) attained their peak frequency 7 to 9 hours after thrombolysis. They occurred most often in anterior myocardial infarction and were often preceded by frequent singular premature beats (r = 0.78).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Usefulness of esmolol in unstable angina pectoris. European Esmolol Study Group.

Esmolol is a new cardioselective beta blocker with unique pharmacokinetic properties resulting in a half-life of only 9 minutes. The present multicenter, randomized, placebo-controlled study examined the hemodynamic and antiischemic effects of this compound given as an adjunctive to conventional medical therapy in 113 patients with unstable angina. Fifty-nine patients received esmolol and 54 received matching placebo infusions. Esmolol was titrated in a step-wise manner at dosages of 2 to 24 mg/min until a 25% reduction in the double product was achieved; thereafter, esmolol was continuously infused for up to 72 hours. Esmolol caused a significant and persistent decline in heart rate and blood pressure throughout the entire study period. Clinical events, such as development of acute myocardial infarction or the need for urgent revascularization, occurred in 3 esmolol compared with 9 placebo patients (p = 0.06). There was also a trend toward reduction of silent ischemia as judged by Holter monitoring (mean [+/- standard deviation] duration/patient/24 hours, 21 +/- 81 minutes in the esmolol and 35 +/- 128 minutes in the placebo groups). Esmolol-related adverse effects were mostly cardiovascular in origin and could be managed promptly by downward dose titration or cessation of drug infusion. Thus, esmolol appears to be a safe and effective drug for patients with unstable angina because it permits a large degree of flexibility in adapting the desired level of beta blockade to the patient's changing clinical presentation.

Adrenergic beta-Antagonists↗
PubMed1991

[Tachycardic arrhythmias in athletes. Incidence, clinical relevance and prognostic significance].

Morphological and functional cardiac changes are found in all active athletes. Of particular interest would appear to be tachycardic arrhythmias, since they have been associated with cases of sudden death during sports activities. In comparison with patients with underlying cardiac disease, few data on the incidence and prognostic significance of tachycardic arrhythmias in athletes are available. The aim of the present study was to characterize and identify prognostically relevant tachycardic arrhythmias in this latter population.

Death, Sudden↗
PubMed1991

Electrocardiographic and antiarrhythmic effects of intravenous amiodarone: results of a prospective, placebo-controlled study.

The antiarrhythmic efficacy of intravenously administered amiodarone was examined in a prospective, randomized, placebo-controlled study that involved 77 patients after coronary artery bypass surgery. Amiodarone was given after surgery in a loading bolus of 300 mg for 2 hours followed by 1200 mg every 24 hours for 2 days and 900 mg every 24 hours for the next 2 days. Amiodarone suppressed both supraventricular and ventricular arrhythmias within 12 hours after the start of therapy. Particularly, the incidence of atrial fibrillation (5% vs 21% in the control group; p less than 0.05) and of nonsustained ventricular tachycardia (3% vs 16%; p less than 0.05) was reduced by amiodarone. Heart rate was slowed (p less than 0.001) and repolarization--as judged by JTc interval--was prolonged compared with the control group (p less than 0.01). In two patients, amiodarone infusion was stopped because of excessive QTc prolongation. No detrimental hemodynamic effects of the drug were observed. Thus the intravenous administration of amiodarone appears to be suitable for patients in whom rapid suppression of symptomatic supraventricular and ventricular arrhythmias is warranted in the presence of left ventricular dysfunction.

Aged↗
PubMed1991

Assessment of coronary artery patency after thrombolytic therapy: accurate prediction utilizing the combined analysis of three noninvasive markers.

The predictability of patency of the infarct-related artery assessed by means of three noninvasive easily obtainable markers was prospectively examined in 82 patients undergoing thrombolysis for their first myocardial infarction. Positive noninvasive markers were defined as follows: 1) early peak creatine kinase (CK) activity less than or equal to 12 h after the start of thrombolysis; 2) greater than or equal to 50% reduction in ST segment elevation; and 3) occurrence of reperfusion arrhythmias within the 1st 90 min of thrombolytic therapy. In 63 (77%) of the 82 patients, Thrombolysis in Myocardial Infarction (TIMI) grade II/III reperfusion was achieved within the 1st 90 min as assessed by coronary angiography. Separate analysis of each marker revealed the following respective values for sensitivity, specificity and positive and negative predictive value regarding prediction of coronary artery patency: CK peak less than or equal to 12 h: 84%, 95%, 98% and 64%; reduction of the ST segment elevation greater than or equal to 50%: 60%, 95%, 97% and 42%; and reperfusion arrhythmias: 63%, 89%, 95% and 43%. The combined analysis of all three markers utilizing a logistic regression procedure showed that CK peak (p = 0.0001) and resolution of the ST segment elevation (p = 0.005), but not the occurrence of reperfusion arrhythmias (p = 0.26), were independent predictors of vessel patency. From this logistic regression procedure, a sensitivity of 100%, a specificity of 90%, a positive predictive value of 97% and a negative predictive value of 100% for prediction of coronary artery patency were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1991

Efficacy and tolerance of the new class IB antiarrhythmic barucainide: an intravenous dose-finding study.

Barucainide is a new class IB antiarrhythmic agent that was studied for efficacy and safety after intravenous administration in patients with severe ventricular arrhythmias. All patients received 80 mg/hr barucainide intravenously for 7 hours or until ventricular arrhythmias were suppressed by greater than 90%. In responders a maintenance dose was given for 24 hours, aimed to achieve steady-state conditions. At baseline and during the treatment and washout periods 24-hour Holter recordings were performed. In addition, electrocardiogram, blood pressure, and plasma concentration of barucainide were measured. In 9 of 12 patients dose titration was effective (mean dose, 185 mg). In six of nine patients arrhythmia suppression persisted during maintenance therapy (mean dose, 18 mg/hr). Plasma concentrations correlated with given doses, rather than with antiarrhythmic efficacy. During the washout period, five patients required more than 12 hours for recurrence of arrhythmias. Treatment was stopped in one patient because of proarrhythmia; one patient had moderate heat sensations. Thus barucainide is a potent class IB agent, with a favorable side effect profile.

Anti-Arrhythmia Agents↗
PubMed1991

The relationship between heart rate and QT interval during atrial stimulation.

The relationship between heart rate and QT interval was investigated during atrial stimulation (intrinsic effect of heart rate) in ten healthy male volunteers prior to and after administration of sotalol. The QT interval in the ECG (paper speed 200 mm/s) was determined at rates of 70, 85, 100, 115, 130, 145, and 160 beats/min and at pacing periods of 180 s each at 30, 60, 120, and 180 s. After a 15-minute period, 2.0 mg sotalol/kg body weight were administered iv and the stimulation protocol was repeated. The analysis of QT interval behavior reveals contradictions to the mathematical implications of Bazett's equation QT = QTc square root of 60/HR, so that the relationship between heart rate and QT interval is not adequately described under the given conditions. After examination of approaches reported in the literature and our own approaches, the expression QT = a e-b (HR-60) is used as a possibility differentially to describe the data by nonlinear regression. The parameters a and b may be interpreted as QT reference value and shortening parameter. The QT reference value a, a parameter in reference to heart rate of 60 beats/min, has a comparable significance to the expression QTc in the Bazett equation. A reduction in the shortening parameter b indicates whether substances influencing the QT interval additionally produce overproportional shortening of the QT interval with increasing heart rate. After administration of sotalol, an increase can be observed in both the QT reference value and also in the shortening parameter. The suggested approach is an attempt to provide a more precise assessment of the QT interval under different conditions.

Adult↗
PubMed1991

Cilazapril in congestive heart failure. A pilot study.

The haemodynamic effects of a single dose of cilazapril 2.5 or 5 mg were studied in 33 patients with stable chronic congestive heart failure who were receiving digitalis and diuretics. Subsequently, a double-blind comparison of the haemodynamic and clinical effects of 3 months' treatment with cilazapril 1.25 to 5 mg daily or placebo in 24 evaluable patients revealed that the acute haemodynamic improvement produced by a single dose of cilazapril was maintained in patients receiving repeated administration of the drug, but not in those randomly allocated the placebo. Acute cilazapril significantly decreased mean arterial pressure, systemic vascular resistance, pulmonary capillary wedge pressure, pulmonary artery pressure and right atrial pressure, while cardiac index and stroke volume index increased at rest and during submaximal exercise. After 3 months' treatment 11 of 13 cilazapril recipients improved their New York Heart Association (NYHA) class compared with 2 of 11 patients treated with placebo. This functional improvement was paralleled by a patient-perceived improvement in general well-being.

Adult↗
PubMed1991

Can we predict sudden cardiac death?

Up to now only 30 to 40% of patients who die suddenly can be identified as likely candidates before the event. Risk factors in these asymptomatic subjects include a familial history of coronary artery disease, high blood cholesterol levels, hypertension, smoking and, more importantly, an abnormal ECG at rest or during exercise. The predictive value of these abnormalities is too low to justify more detailed clinical investigations in most of these asymptomatic subjects. Exceptions might be the group of patients with multiple risk factors and competitive sportsmen. Sudden cardiac death is a well known complication in patients with hypertrophic and dilated cardiomyopathy. Risk factors in hypertrophic cardiomyopathy include a familial history of this disease, syncope and increasing age. Furthermore, in the adult, the presence of nonsustained episodes of ventricular tachycardia during Holter monitoring seems to indicate an increased risk of sudden cardiac death. In idiopathic dilated cardiomyopathy, the presence of frequent episodes of ventricular pairs and/or episodes of ventricular tachycardia during Holter monitoring, together with a reduced left ventricular ejection fraction, characterises the patient at risk of sudden cardiac death. In patients with coronary artery disease, the patient at risk of sudden cardiac death can be identified by investigating the following: coronary anatomy; global and regional left ventricular function; the presence of ischaemia during rest and/or exercise; the presence of late potentials, by means of the signal-averaged ECG; the presence of spontaneous ventricular arrhythmias (especially sustained and nonsustained ventricular tachycardia); and the results of electrophysiological testing. On the basis of these investigations, 3 subgroups can be distinguished: patients at low risk, medium risk, and high risk of sudden cardiac death.

Death, Sudden↗
PubMed1991

[Arrhythmia and anti-arrhythmia therapy as prognostic risks].

The incidence of sudden death is estimated to be 0.25%/year in the industrialized world. 30 to 40% of patients are known to be at major risk before they succumb sudden death. Etiology is usually coronary heart disease (75%), dilated and hypertensive cardiomyopathy as well as valvular disease. 75% of patients dying suddenly die from ventricular fibrillation. The most common mechanism of sudden cardiac death in heart failure is sustained ventricular tachycardia deteriorating into ventricular fibrillation, the initiating factors being single ventricular beats, ventricular pairs or nonsustained ventricular tachycardia (trigger mechanism). At least 50% of patients dying during Holter monitoring have been on antiarrhythmic treatment during the time of sudden death and this percentage is increased to 70% in patients dying from torsade de pointes ventricular tachycardia. The question that has arisen is whether suppression of such arrhythmias by antiarrhythmic agents will reduce the incidence of sudden cardiac death. Unfortunately, the patient group at highest risk - low ventricular ejection fraction and high incidence of nonsustained ventricular tachycardia episodes during 24 hour-monitoring and thus, the group most in need of arrhythmia suppression - has the lowest responder rate as well as the highest incidence of serious toxicity. Until the suppression of those arrhythmias by antiarrhythmic agents is demonstrated to improve prognosis in this patient group, routine use of antiarrhythmic agents cannot be recommended in this patient population.

Anti-Arrhythmia Agents↗
PubMed1991

[Incidence of tricuspid valve prolapse].

The incidence of tricuspid valve prolapse and its association with mitral valve prolapse was studied in 100 patients with right- and left-ventricular angiography. Coronary artery disease was present in 81 patients (pts), a dilative cardiomyopathy in 6 pts, and a hypertrophic cardiomyopathy in 2 pts. 11 pts were angiographically normal. A total of 27 pts had a tricuspid valve prolapse, and 15 pts had a mitral valve prolapse. In 19 pts prolapse of the tricuspid valve was isolated, and in 8 pts it was associated with a mitral valve prolapse. The associated finding of a prolapse of the tricuspid and mitral valve was statistically significant (p less than 0.02). Patients with a tricuspid valve prolapse experienced a higher right-ventricular ejection fraction (58 + 10 vs 53 +/- 10%; p less than 0.05) and smaller end-systolic right ventricular volume indices (39 +/- 16 vs 47 +/- 17 ml/m2; p less than 0.05) compared to those without tricuspid valve prolapse. There was no further difference in clinical and hemodynamic parameters between those with and those without tricuspid valve prolapse. The clinical significance of a tricuspid valve prolapse is still undefined.

Adolescent↗
PubMed1990

Echocardiographic evaluation of patients with clinically suspected arterial emboli.

153 patients (mean age 42 years, range 16-60) who had arterial embolic events were examined prospectively by transthoracic and transoesophageal echocardiography. Patients older than 60 years and those with evidence of extracranial carotid artery occlusive disease were excluded. 84 patients had a cerebral ischaemic event, 50 patients had embolic events in an abdominal organ or limb, and 19 patients had acute retinal ischaemia. The transthoracic echocardiographic examination was normal in 92 patients (60%), whereas only 65 patients (42%) had normal findings after both transthoracic and transoesophageal examination (p less than 0.005). Intracardiac masses, including valvular vegetations, were found in 39 patients (25%), including 27% of patients with cerebral embolism and 32% of these with peripheral embolism, but in none of the patients with retinal ischaemia (p less than 0.001). 47 patients (31%) had valvular disease, 10 (7%) had wall motion abnormalities, 23 (15%) had abnormalities of the interatrial septum, and 9 patients (6%) had diseases of the thoracic aorta. Cardiovascular abnormalities were frequently found by echocardiography in patients with arterial emboli. The transesophageal technique significantly increased the chance of detecting such abnormalities, especially intracardiac masses.

Adolescent↗
PubMed1990

[The thrombolytic treatment of acute and subacute recurrent pulmonary embolism with recombinant tissue plasminogen activator].

Thrombolytic treatment with recombinant tissue plasminogen activator (rt-PA) at a dosage of 40-150 mg was given to five patients with acute and five with recurrent pulmonary emboli (three women and seven men; mean age 54 [30-78] years). Mean pulmonary artery pressure fell from 29 +/- 7 mm Hg before to 20 +/- 5 mm Hg after treatment (P = 0.001), and in recurrent emboli from 47 +/- 19 to 18 +/- 10 mm Hg (P = 0.01). Pulmonary vascular resistance fell from 546 +/- 262 to 318 +/- 116 dyn.s.cm-5 (P = 0.02) in the former group and from 993 +/- 583 to 377 +/- 438 dyn.s.cm-5 (P = 0.01) in the latter. Pulmonary arteriograms were assessed using the Miller index. This indicated a drop from an average of 23 points before to an average of 10.5 points after treatment. Mild bleedings occurred in all patients, but in two it was severe enough to require discontinuation of treatment. These results demonstrate that rt-PA is highly effective as a thrombolytic agent in acute and in subacute recurrent pulmonary embolism.

Acute Disease↗
PubMed1990

Coronary reperfusion studies with pro-urokinase in acute myocardial infarction: evidence for synergism of low dose urokinase.

Pro-urokinase is a single chain precursor of two chain urokinase, which has been shown to induce fibrin-selective plasminogen activation. In the present study, thrombolytic efficacy of 9 million U of glycosylated pro-urokinase administered intravenously was compared with that of a combined regimen utilizing 4.5 million U of pro-urokinase and 0.2 million U of urokinase. Seventy-five patients with a first myocardial infarction were randomized to receive high dose pro-urokinase (n = 40, group A) or the combination therapy (n = 35, group B). Reperfusion of the infarct-related artery was assessed by repeat coronary angiography. Thrombolysis in Myocardial Infarction trial (TIMI) grade II or III reperfusion was achieved in 73% of group A patients compared with 66% of group B patients (p = NS). A trend toward faster reopening of the infarct-related artery was observed in patients in group B. Coronary artery reocclusion occurred in 5 (10%) of 49 patients in whom angiography was repeated within 36 h after the start of therapy. Clot-selective thrombolysis was indicated by a minimal fibrinogen decline (15% and 13%, respectively, in groups A and B). Alpha 2-antiplasmin levels, however, decreased more rapidly in patients in group B (p less than 0.05). This finding and the equivalent reperfusion rate in the combined treatment group strongly suggest synergistic interaction between these two thrombolytic agents. In summary, the high incidence of reperfusion, the low rate of early reocclusion and the paucity of side effects, particularly with regard to bleeding complications, indicate that pro-urokinase possesses the characteristics of an ideal thrombolytic agent.

Drug Synergism↗
PubMed1990

ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance.

These findings permit the following conclusions on cardiac changes induced by high-performance sports and high levels of training. Sinus bradycardia and AV block can frequently be observed in athletes, but they do not require attention as long as they are asymptomatic or do not produce pauses exceeding 4 seconds. Persistent rather than transient second-degree AV block or Mobitz second- or third-degree AV block is an extremely unusual finding even in athletes and should be considered a sign of organic lesions until proved otherwise. Supraventricular and AV node ectopic beats are not more frequent in athletes than in the general population except for atrial fibrillation. WPW syndrome is of particular importance, since rapid conduction to the ventricle via the accessory AV pathway is possible, especially if there is a tendency toward atrial fibrillation. Likewise caution is required in athletes with hypertrophic cardiomyopathy. Here hemodynamic deterioration must be anticipated with the occurrence of supraventricular tachycardia. Simple ventricular arrhythmias occur among athletes with the same frequency as in the general population, but they usually disappear with exercise. The occurrence of complex ventricular forms of arrhythmia should always prompt cardiologic examination in search of underlying cardiac disease, particularly hypertrophic or dilated cardiomyopathy. The presence of ventricular arrhythmias without evidence of underlying heart disease does not indicate a special or increased risk of sudden cardiac death. A higher incidence of right and/or left ventricular hypertrophy, exercise-reversible ST elevation, and exercise-reversible changes in T waves (T negativity, sharp and/or excessive T waves) can be considered physiologic changes in the ECGs of athletes. These changes correlate closely with the type of sports activity and degree of training and are reversible when the activity is stopped. Horizontal ST segment depression are by contrast very rare in athletes and should always be clarified by cardiologic examination. Exercise-induced sudden cardiac death in athletes is unusual without preexisting heart disease. The cause of sudden cardiac death among athletes less than 40 years of age can be predominantely ascribed to congenital heart diseases (such as hypertrophic cardiomyopathy or coronary anomalies). In athletes more than 40 years of age and with increasing age, coronary heart disease is the most frequent autopsy finding. A corresponding risk stratification should take these partial dangers into account.

Arrhythmias, Cardiac↗
PubMed1990

Improved morphologic characterization of atrial septal aneurysm by transesophageal echocardiography: relation to cerebrovascular events.

Transthoracic and transesophageal echocardiography was performed in 23 consecutive adult patients with an atrial septal aneurysm. In three patients with a cerebrovascular event the diagnosis was established by the transesophageal approach only. Interatrial shunting on transthoracic imaging with use of echocardiographic contrast imaging or Doppler color mapping, or both, was detected in 7 (41%) of 17 patients. On performing contrast imaging in combination with color flow mapping during transesophageal echocardiography, positive shunting was demonstrated in 15 (83%) of 18 patients. Echocardiographic identification of multiple fenestrations (n = 4) and thrombus within the aneurysm (n = 2) could be achieved for the first time by transesophageal ultrasound application. Cerebrovascular events occurred in 12 (52%) of 23 patients and were regarded as being definitely thromboembolic in 10 (43%); 8 (67%) of the 12 patients had repeated cerebral events. Except for mitral valve prolapse in one patient, no other potential cardiac source of embolism could be identified despite the use of transesophageal echocardiography. A thickening of the aneurysmal membrane greater than or equal to 5 mm was found in 9 (75%) of 12 patients with versus 3 (27%) of 11 patients without a cerebrovascular event (p less than 0.05); this proved to be the only significant difference between the two patient groups. The mechanism of embolization may be both primary thrombus formation within the aneurysm and paradoxic embolization through an interatrial communication as demonstrated by the findings in two patients. It is concluded that atrial septal aneurysm is a cardiac abnormality with thromboembolic potential. In patients with this lesion and a history of an embolic event, long-term anticoagulant therapy is indicated.

Echocardiography↗
PubMed1990

Beta-blocking agents vs. antiarrhythmic interventions in heart failure complicated by arrhythmias.

Approximately 40-50% of the patients with end-stage cardiac failure (either ischemic or nonischemic) die suddenly and unexpectedly, most probably from ventricular fibrillation. It is unclear whether the complex ventricular arrhythmias observed in large numbers of these patients were related to the mode of death. Theoretically, it seems quite reasonable to attempt to suppress the development of life-threatening ventricular arrhythmias (e.g., sustained ventricular tachycardia or ventricular fibrillation) in those patients. If antiarrhythmic drug therapy is ineffective, alternative antiarrhythmic interventions (antiarrhythmic surgery or implantation of an automatic implantable cardioverter defibrillator) should be considered. In patients with so-called potentially malignant ventricular arrhythmias (e.g., nonsustained ventricular tachycardia), antiarrhythmic drug therapy remains controversial as presently there is no definitive proof that this therapy prolongs life or reduces the incidence of sudden cardiac death. In patients with end-stage cardiac failure, beta-blockade can result in a decrease in resting tachycardia, improvement in clinical heart failure symptoms, and increase in work load capacity. It remains controversial whether treatment with these agents can also improve prognosis and prevent sudden cardiac death. Therefore, at this time, only patients in the earlier stages of this clinical syndrome and with clinical signs of markedly increased sympathetic tone can be treated with low doses of beta-blockers.

Adrenergic beta-Antagonists↗