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Biomedical subjects

M Manz

Publications and source records attributed to M Manz.

At least 73 records · Page 4Linked to original sources
PubMed1993

Supraventricular tachycardia and pre-excitation syndromes: pharmacological therapy.

Tachyarrhythmias which originate above the bifurcation of the bundle of His or incorporate tissue proximal to it are classified as supraventricular tachyarrhythmias (SVT). Primary treatment of SVT attempts to influence the underlying disease. Therapy is subdivided into drug therapy, electrotherapeutic tools (e.g. antitachycardia pacemakers, catheter ablation) and antiarrhythmic surgery. Antiarrhythmic agents which slow conduction and suppress premature beats are efficient for emergency and long-term treatment of supraventricular tachycardias. We evaluated some of the most relevant antiarrhythmic drugs for SVT including propafenone, diprafenone, cibenzoline, lorcainide and sotalol; in addition, usage and efficacy of quinidine/verapamil, disopyramide, amiodarone, ajmaline, adenosine and flecainide are summarized. The principles for acute management of tachycardia episodes with narrow and broad complexes are outlined. The reason for the selection as well as the efficacy in the termination of the tachycardias is described for different antiarrhythmic agents including verapamil, adenosine, ajmaline, propafenone and flecainide.

Ajmaline↗
PubMed1993

Surgical treatment of the Wolff-Parkinson-White syndrome--experiences in 120 patients.

Since January 1984, 120 patients (78 male, 42 female; aged 3 to 66 years) with the Wolff-Parkinson-White (WPW) syndrome have been operated upon. The indication for surgery was documented recurrent, paroxysmal tachycardia refractory to medical treatment in 118 cases. Twenty-two patients (18%) had additional heart disease. One hundred and twenty patients had a total of 140 accessory pathways (AP). AP were localized at the left free wall in 63% (87 AP), at the right free wall in 24% (35 AP), and septally in 13% (18 AP). Sixteen patients (13%) had multiple AP (12 patients had two and four patients had three AP), 124 AP were known pre-operatively (88%), 133 were localized intra-operatively (94%) and seven were diagnosed during re-operation (6%). Surgery in 28 patients with left lateral AP was via the epicardial approach and the endocardial approach in 59. Of 15 patients with right lateral AP, the surgical approach was epicardial in two and transmural in 13. A cryosurgery was also used in 117 patients. Fifteen patients suffered recurrences, in 12 of whom repeat surgery was required. One hundred and thirty-six AP (97%) were dissected successfully, of which 14 (10%) were ablated during re-operation. All patients survived the initial operation, but two patients died after re-operation. One patient is pacer-dependent due to persisting postoperative atrioventricular (AV) block. We conclude that surgical dissection of accessory pathways can be offered as an alternative to non-surgical treatment modes, at a low risk and with a high success rate.

Adolescent↗
PubMed1993

Effects of antiarrhythmic drugs on epicardial defibrillation energy requirements and the rate of defibrillator discharges.

Antiarrhythmic drugs are commonly used with the implantable cardioverter/defibrillator to treat recurrent ventricular tachyarrhythmias. Since various antiarrhythmic drugs have been reported to alter defibrillation threshold, an important question is whether the device will provide adequate energy for defibrillation during long-term follow-up and to what extent antiarrhythmic drug treatment will affect defibrillation energy requirements. To answer these questions, the defibrillation thresholds were determined in 20 patients using an epicardial patch-patch lead configuration at the time of implantation and at the time of pulse generator replacement. During a mean follow-up period of 24 +/- 6 months, the defibrillation threshold increased significantly from 14.2 +/- 3.7 joules to 18.3 +/- 5.5 joules in the entire group (P < 0.05). This increase in defibrillation threshold was due to a marked elevation of defibrillation energy requirements in the subgroup of patients taking amiodarone compared with patients receiving mexiletine. Based on these results it is mandatory to retest defibrillation threshold at any time of pulse generator replacement to guarantee continued effectiveness. In particular, if amiodarone treatment is initiated after implantation of a defibrillator, it is recommended to reevaluate defibrillation threshold to ensure an adequate margin of safety.

Amiodarone↗
PubMed1993

Efficacy and safety of combination therapy with amiodarone and type I agents for treatment of inducible ventricular tachycardia.

In a prospective study the efficacy of amiodarone in combination with the three Class I drugs mexiletine, flecainide, or encainide was evaluated consecutively in 12 patients with recurrent ventricular tachycardias (VT) by programmed stimulation. None of the tested drug combinations suppressed induction of sustained VT. The combination of amiodarone with Class IC drugs flecainide and encainide prolonged the cycle length of VT significantly, whereas the combination with mexiletine did not have the same degree of slowing on the VT cycle length. Several proarrhythmic effects occurred during the combination therapy with encainide: (1) frequent, spontaneous recurrences of hemodynamically well tolerated VT in four patients; (2) enhanced inducibility of VT in three patients; (3) impaired termination of VT in three patients. Though a marked increase in QRS and QTc intervals was observed by combined treatment with encainide, no significant correlation could be established between aggravation of arrhythmia and plasma levels of encainide, degree of QRS widening, JT or QTc prolongation. The only predictor for the occurrence of proarrhythmic events was found in left ventricular ejection fraction. These findings suggest that in patients refractory to amiodarone alone or a combination with mexiletine, the combined treatment of amiodarone with other Class IC drugs prolongs the VT cycle length but does not suppress induction of VT during programmed stimulation. Combination therapy of amiodarone with encainide was associated with a high incidence of proarrhythmic effects.

Adult↗
PubMed1993

Patient acceptance of the implantable cardioverter defibrillator in ventricular tachyarrhythmias.

Besides surgical problems, recipients of implantable cardioverter defibrillators (ICDs) are faced with psychological and social adjustments. Successful ICD therapy is influenced by the patients' perceived concerns regarding device, discharge, changes in life style, and complications. In order to assess patients' acceptance of the ICD, the psychological profile of 57 consecutive patients was evaluated using a specifically designed questionnaire and the State Trait Anxiety Inventory (STAI). The results showed that 20 patients stated fear of ICD discharge, 12 patients revealed physical discomfort due to the device, and limited quality-of-life occurred in 8 patients. Fifty-five of 57 patients answered that it was worth having an ICD device implanted, 30 (53%) patients returned to active life, and 56 (98%) would advise another patient to undergo implantation if necessary. Overall, there was only a slight, but insignificant, decrease in the level of anxiety within the total patient population after ICD implantation. However, a comparison of two subgroups indicated that the state of anxiety was significantly higher in patients < 50 years of age as well as in patients having received > 5 shocks versus those > 50 years of age and having experienced < 5 shocks. In general, the acceptance of the ICD as a tool in managing life-threatening ventricular tachyarrhythmias is high. Besides the increased survival rate, quality-of-life and patient acceptance are important criteria for successful ICD therapy.

Activities of Daily Living↗
PubMed1993

Mechanical dilatation rather than plaque removal as major mechanism of transluminal coronary extraction atherectomy.

Atherectomy with the transluminal extraction endarterectomy catheter (TEC) is a new approach for treatment of coronary artery disease, which continues to undergo FDA investigational studies. The major mechanism of the TEC device should be excision of plaque and its removal due to suction applied through an attached vacuum. We report about the acute results in 24 patients treated with TEC atherectomy in native vessels and the outcome of 18 patients who, until recently, underwent follow-up catheterization after 6 months. The procedure was successful (residual stenosis less than 50%) in 7 of 24 patients with TEC atherectomy alone (29%); 15 of 24 patients (65%) required additional PTCA in order to achieve angiographic success (10 of 24) or to treat total occlusion (2 of 24) or distal embolization (3 of 24) following atherectomy. One TEC attempt failed due to guiding catheter problems, another major complication was a vessel perforation leading to a non-Q wave infarction. The minimal residual diameter after passage of the stenosis (prior to additional PTCA) with the 5.5 Fr catheter (n = 14) was 1.5 +/- 0.2 mm, with the 6 Fr catheter (n = 9) 1.8 +/- 0.4 mm, and 2.2 +/- 0.2 mm using the 7 Fr catheter (n = 10). The histologic findings revealed intimal cells, fibrous tissue, and homogenate with no identifiable tissue in five cases (21%), whereas in 17 patients (72%) light microscopy could only assess blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[Current treatment of supraventricular tachycardia: drug therapy].

Recurrent supraventricular arrhythmias are associated with palpitations, weakness, syncopes, etc. Pharmacological treatment with antiarrhythmic agents aims to interrupt the tachyarrhythmia episodes (acute therapy) and to stabilize sinus rhythm thereafter (chronic therapy). Due to the newer curative options (transvenous ablation), the segment for the pharmacological therapy is shrinking. Treatment with antiarrhythmic agents is still indicated, if the recurrence of tachycardia episodes can be sufficiently controlled by a well-tolerated antiarrhythmic regimen. In the cohort of atrial fibrillation, total mortality and mortality from cardiovascular causes were increased under the influence of quinidine. The risk must, therefore, be weighed against the anticipated benefit from as well as the likelihood of arrhythmia suppression, before treating a patient with class I antiarrhythmic drugs. In some cases, reduction of ventricular rate by calcium antagonists will be the better choice. In case of recurrent atrial fibrillation without or with minimal structural abnormalities, propafenone or flecainide are recommended. Sotalol, and in rare cases amiodarone, will be applied in coronary artery disease. Atrial fibrillation of recent onset may be interrupted by bolus injection of ajmaline, propafenone, or flecainide. In case of impaired cardiac function, intravenous amiodarone can be applied safely. In summary, the scientific basis for the treatment of supraventricular tachycardias has been strengthened by clinical trials. Careful evaluation of the individual patient is warranted prior to institution of the pharmacological treatment.

Anti-Arrhythmia Agents↗
PubMed1992

Effects of chronic amiodarone therapy on defibrillation threshold.

In a prospective and parallel, randomized study, the long-term stability of epicardial defibrillation threshold was evaluated in 22 patients, using a patch-patch lead configuration at the time of implantation and generator replacement. The concomitant antiarrhythmic drug treatment consisted of either mexiletine (720 mg/day) or amiodarone (400 mg/day) and was administered to patients in a randomized and parallel manner. During a mean follow-up of 24 +/- 6 months, the defibrillation threshold increased significantly from 14.3 +/- 2.8 to 17.9 +/- 5.3 J (p < 0.05) for the entire patient group. The increase in the chronic defibrillation threshold was due to a marked increase in defibrillation energy needs in the subgroup of patients receiving amiodarone. Whereas no significant change in the defibrillation threshold was documented in the subgroup of patients receiving mexiletine, the mean defibrillation threshold increased from 14.1 +/- 3.0 to 20.9 +/- 5.4 J (p < 0.001) in those receiving amiodarone. In all patients with increased defibrillation thresholds, reevaluation showed a reduction in the defibrillation threshold after discontinuation of antiarrhythmic drug therapy. The only variable associated with an increase in the chronic defibrillation threshold was amiodarone treatment. These findings suggest that the defibrillation threshold should be measured at each generator replacement and in case of a change in antiarrhythmic drug treatment. In particular, if amiodarone treatment is initiated, it is recommended that the defibrillation threshold should be reevaluated to ensure an adequate margin of safety.

Amiodarone↗
PubMed1992

Pharmacologic treatment of supraventricular tachycardia: the German experience.

Tachyarrhythmias that originate above the bifurcation of the bundle of His or in tissue proximal to it are classified as supraventricular tachyarrhythmias (SVTs). Primary treatment of SVT tries to influence the underlying disease. Symptomatic therapy is subdivided into drug therapy, electrotherapeutic tools (e.g., antitachycardia pacemakers, catheter ablation), and antiarrhythmic surgery. Antiarrhythmic agents that slow conduction and suppress premature beats are efficient for emergency and long-term treatment of SVTs. We evaluated some of the most relevant antiarrhythmic drugs in SVT, including propafenone, diprafenone, cibenzoline, sotalol, and diltiazem; in addition, usage and efficacy of quinidine/verapamil, disopyramide, amiodarone, ajmaline, adenosine, and flecainide are summarized. In 1990, the case load of supraventricular arrhythmias per physician in Germany was more than 30 patients seen per month. About 50% of them were treated with drug therapy; i.e., approximately 17 patients were treated with antiarrhythmic drugs per month per physician for supraventricular arrhythmias. The most important antiarrhythmic agents used in Germany are propafenone (40%), combination of quinidine and verapamil (23%), sotalol (12%), disopyramide (6%), flecainide (6%), and other (13%).

Anti-Arrhythmia Agents↗
PubMed1992

Hemodynamic effects of amiodarone during acute and chronic treatment in patients with recurrent sustained ventricular tachycardia.

In 15 patients with recurrent ventricular tachycardia, the hemodynamic effects of amiodarone were evaluated under oral loading (1000 mg/day for 14-16 days) and during chronic treatment (600 mg/day for a further 10 weeks). In all patients, coronary artery disease was present with a mean ejection fraction of 37%+/- 10%. The cardiac output during the sinus rhythm, as determined by thermodilution, did not change significantly during loading with amiodarone. During ventricular tachycardia, the cardiac output increased from 3.7 +/- 1.3 to 4.5 +/- 1.6 1/min under the influence of amiodarone in 5 patients. Echocardiographic measurements of the left ventricle dimensions did not show a directed change of the enddiastolic and endsystolic diameters and the fraction shortening at the end of the loading period and after 3 months of maintenance therapy. No negative inotropic effect of amiodarone could be demonstrated in patients with recurrent ventricular tachycardia and impaired left ventricular function due to coronary artery disease.

Aged↗
PubMed1992

Electrophysiological and haemodynamic effects of lidocaine and ajmaline in the management of sustained ventricular tachycardia.

The electrophysiological and haemodynamic effects of lidocaine (100 mg) and ajmaline (50 mg) were evaluated while attempting to interrupt sustained ventricular tachycardia. The study was performed as a prospective, non-blinded, randomized investigation in 61 patients. Lidocaine terminated ventricular tachycardia in four of 31 patients, ajmaline in 19 of 30 patients (P less than 0.001). QRS and RR intervals during ventricular tachycardia were prolonged by ajmaline from 164 +/- 28 ms to 214 +/- 49 ms and from 371 +/- 86 ms to 479 +/- 137 ms (P less than 0.001), respectively; lidocaine did not influence these parameters. The duration of the return cycles after termination of ventricular tachycardia did not differ between the two groups. Lidocaine did not change cardiac output during ventricular tachycardia whereas cardiac output increased significantly under ajmaline from 3.5 +/- 1.21.min-1 to 5.5 +/- 1.91.min-1 (P less than 0.001). It is concluded that anti-arrhythmic agents such as ajmaline, which slow conduction velocity and prolong refractoriness, are more effective than lidocaine in the medical treatment of haemodynamically stable, sustained ventricular tachycardia.

Ajmaline↗
PubMed1992

Long-term therapy of antitachycardia pacing for supraventricular tachycardia.

Long-term antitachycardia pacing therapy with the InterTach 262-12 and 262-16 was evaluated in 32 consecutive patients (mean age 50 +/- 13 years) with recurrent, drug refractory supraventricular tachycardia. AV nodal reentrant tachycardia was present in 20 patients, Wolff-Parkinson-White syndrome in ten patients, and a reentrant tachycardia due to Mahaim fibers in one patient. During follow-up of 39 +/- 17 months, 250 persistent tachycardia episodes occurred in 22 patients. By adjusting detection and termination mode, recurrent supraventricular tachycardia could be controlled in 19 of 32 patients (60%) by antitachycardia pacing alone. Concomitant antiarrhythmic drug therapy was required in ten of 32 patients (30%). During follow-up antitachycardia pacing became ineffective in three patients (10%). Thus, chronic antitachycardia pacing proved to be safe and effective in selected patients with drug refractory supraventricular tachycardia and could significantly improve quality of life by rapid termination of recurrent supraventricular tachycardia episodes.

Algorithms↗