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Biomedical subjects

K H Kuck

Publications and source records attributed to K H Kuck.

At least 163 records · Page 9Linked to original sources
PubMed1985

[Right atrial thrombus formation following transvenous catheter ablation of the AV conduction system].

A case is reported in which the formation of a right atrial mass was detected by two-dimensional echocardiography 3 weeks after successful transvenous electrical ablation of the atrioventricular junction had been performed. The mass was attached to the atrial septum at the site where the electrode catheter used for the ablation had been located and it exhibited no mobility. It was interpreted as a right atrial thrombus induced by the ablation procedure. Although no pulmonary embolic events have been observed during a 7-month follow-up period, right atrial thrombus formation must be considered as a potentially dangerous complication of transvenous catheter ablation to control supraventricular arrhythmias.

Adult↗
PubMed1985

Hypertrophic cardiomyopathy: non-invasive assessment of diastolic and systolic functional parameters in relation to heart rate.

Hypertrophic cardiomyopathy (HC) is characterized by reduced left ventricular compliance and subsequent filling abnormalities. To study the pathophysiologic changes in parameters of left ventricular systolic and diastolic performance as a function of increasing heart rate 14 patients with HC (32 +/- 12 yrs; 11 M, 4 F) and 4 normal individuals were subjected to equilibrium radionuclide ventriculography (99mTc-labelled red blood cells) at rest and during incremental right atrial pacing; heart rate was increased in steps of 20 beats per min from basal state to the individual symptom-limited endpoint. Mean symptom-limited heart rate was 141 +/- 28 in HC and 160 in normals (p less than .01.). At each pacing level filling and ejection parameters as well as the left ventricular endsystolic (LVESV) and enddiastolic volume (LVEDV) were determined relative to resting volumes at a heart rate of 78 +/- 8. At the individual maximal pacing rate HC revealed a decline in LVEDV to 61 +/- 4% (p less than .001) and an increase in LVESV to 117 +/- 14% (p less than .001) resulting in decreasing ejection fractions at heart rates above 120. Peak LV filling rates initially increased but subsequently decreased steeply at heart rates above 100; peak LV ejection rates in HC showed a similar pattern with increasing frequency. Time intervals to peak ejection and peak filling rate did not differ from normal. Thus, patients with HC demonstrated combined left ventricular diastolic and systolic abnormalities with increasing heart rate leading into a low-input low-output circulatory state. This probably explains not only the symptoms associated with HC, but also supports the concept of "hemodynamic syncope" in HC.

Adolescent↗
PubMed1984

Tachycardia prevention by programmed stimulation.

Ten patients with an atrioventricular accessory pathway were studied by standard electrophysiologic techniques to determine if reentrant tachycardia can be prevented in these patients by delivery of a single extrastimulus, applied at a critical time after the tachycardia-initiating stimulus (or stimuli). In all 10 patients, reentrant tachycardia was reproducibly induced from the high right atrium with a single premature beat, and initiation of tachycardia could be prevented from the same site by a second premature beat. This second extrastimulus was effective if delivered within a zone that began 10 ms outside of the effective refractory period of the tachycardia-initiating stimulus and averaged 50 ms in width. This zone was termed the "preventive zone." The width of the preventive zone was independent of the initial tachycardia interval and the tachycardia cycle length. Prevention of reentrant tachycardia was always possible with a single atrial extrastimulus, whereas termination of the ongoing tachycardia required at least 2 atrial extrastimuli or stimulation from the right ventricle.

Adolescent↗
PubMed1984

Electrophysiologic and clinical effects of intravenous and oral encainide in accessory atrioventricular pathway.

The effect of intravenous and oral encainide was studied in 12 patients with an accessory atrioventricular pathway (AP). Eight patients had Wolff-Parkinson-White syndrome and 4 had a concealed AP. Electrophysiologic studies were performed before and after intravenous encainide, 1.0 to 1.5 mg/kg, and 4 weeks after oral encainide, 75 to 200 mg/day. Mean follow-up was 19 +/- 6 months. During sinus rhythm, intravenous and oral encainide significantly prolonged the AH and HV intervals. In patients with Wolff-Parkinson-White syndrome, after intravenous encainide, anterograde conduction over the AP was blocked in 3 patients, and the anterograde effective refractory period (ERP) of the AP was markedly increased in 3. Five of these 6 patients had a control value of the anterograde AP ERP of less than 270 ms. Anterograde AP block was maintained in 2 patients after oral encainide therapy. Retrograde AP block or marked increase of retrograde AP ERP was seen in 4 of 9 patients after intravenous encainide and in 2 of 7 after oral therapy. Encainide either prevented induction of circus movement tachycardia (intravenous, 4 of 11 patients; oral, 2 of 7 patients) or significantly prolonged tachycardia cycle length (intravenous, 7 of 11 patients; oral, 5 of 7 patients). During long-term follow-up of 9 patients, 6 patients had no recurrences of tachyarrhythmia after individual adjustment of encainide dosage. One patient had worsening of supraventricular tachycardia after intravenous encainide therapy and 4 patients complained of visual blurring; in 1 patient it was so severe that it required withdrawal of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

Multiple anterograde and retrograde AV nodal pathways: demonstration by multiple discontinuities in the AV nodal conduction curves and echo time intervals.

Programmed electrical cardiac stimulation was performed in a 40-year-old man with documented recurrent, sustained ventricular tachycardia which was refractory to standard medical therapy. Both the presence of several discontinuities in the AV nodal conduction curves during atrial and ventricular stimulation and the time intervals of the AV nodal echo phenomena suggested the presence of multiple AV nodal pathways. The results of this study are of interest in further increasing our understanding of the electrophysiologic behavior of the human AV node.

Adult↗
PubMed1983

Pharmacokinetics of tocainide in patients with renal dysfunction and during haemodialysis.

The disposition of tocainide was studied in 15 patients with renal dysfunction. In 9 with total renal failure, the plasma half-life ranged from 16.6 to 42.7 h and total plasma clearance from 35 to 94 ml/min. The longest half-lives were found in 1 patient with cirrhosis, 3 taking the enzyme inhibitor allopurinol, and 1 on cimetidine. The mean half-life in the remaining patients was 22.3 +/- 4.8 h (+/- SD). During a 4 h haemodialysis, the half-life in the 9 patients decreased to 8.5 +/- 4.6 h, which was calculated to correspond to removal of 25 +/- 14% of the drug from the body. In 6 patients with impaired renal function (creatinine clearance 10-55 ml/min) the tocainide half-life ranged from 13.2 to 22.0 h and total plasma clearance from 72 to 122 ml/min. One patient was taking allopurinol and 1 dihydralazine, and the mean half-life in the others was 19.2 +/- 4.0 h. The apparent volume of distribution was similar to that found previously in healthy subjects. The results suggest that tocainide elimination is predictably reduced in patients with renal disease.

Aged↗
PubMed1983

Observations on the antidromic type of circus movement tachycardia in the Wolff-Parkinson-White syndrome.

In the differential diagnosis of tachycardias showing a wide QRS complex and having a 1 to 1 relation between ventricular and atrial events, a supraventricular tachycardia with anterograde conduction over an accessory pathway and retrograde conduction by way of the specific conduction system must be considered. Five patients showing this type of circus movement tachycardia were studied by programmed electrical stimulation of the heart. Sudden changes in the tachycardia cycle length were observed in these patients that were based on changes in the VH interval. This finding suggested a change in the reentrant circuit with anterograde conduction over the accessory pathway but retrograde conduction sometimes occurring over the right bundle branch and at other times over one of the two divisions of the left bundle branch system. Characteristically, the tachycardia cycle length changed suddenly depending on the bundle branch used in retrograde direction. In one patient, an important difference was also observed between the anterograde effective refractory period of the accessory bypass (280 ms) and the shortest RR interval between preexcited QRS complexes during atrial fibrillation (measuring 190 ms). It is postulated that the short RR intervals during atrial fibrillation in the Wolff-Parkinson-White syndrome could result from bundle branch reentry after activation of the ventricles over the accessory pathway.

Adolescent↗
PubMed1983

Haemodynamic and cardiac metabolic effects of the new beta 1 agonist prenalterol in patients with cardiac failure.

Prenalterol, a beta 1 selective agonist, exerts a positive inotropic action in animal studies as well as in human volunteers and is effective when administered orally. To assess its immediate haemodynamic and myocardial metabolic effects, we studied the response to prenalterol (50 and 100 micrograms kg-1 given intravenously by cardiac catheterization) in 15 patients with congestive heart failure secondary to coronary artery disease or non-ischaemic cardiomyopathy. At peak effect, cardiac index increased from 2.6 +/- 0.5 to 3.2 +/- 0.8 l min-1 m2 (mean +/- S.D.) (P less than 0.001); peak rate of left ventricular pressure development rose from 963 +/- 242 to 1335 +/- 411 mmHg s-1 (P less than 0.001); left ventricular end-diastolic pressure fell from 25 +/- 6 to 17 +/- 7 mgHg (P less than 0.001); coronary sinus blood flow increased from 113 +/- 39 to 148 +/- 55 ml min-1 (P less than 0.01); myocardial oxygen consumption was augmented from 12.7 +/- 3.9 to 16.4 +/- 5.8 ml min-1 (P less than 0.001); and heart rate increased slightly (from 76 +/- 12 to 86 +/- 14 beats min-1; (P less than 0.05)). No significant changes occurred in left ventricular systolic pressure, stroke volume index, myocardial lactate extraction rate and myocardial arteriovenous oxygen difference, and no patients developed angina, ECG changes or ventricular arrhythmias. Infusion of prenalterol effectively improved haemodynamic function and cardiac metabolism in cardiomyopathy. Therefore this agent deserves further investigation to evaluate its possible role for the long-term therapy of patients with chronic heart failure.

Adrenergic beta-Agonists↗
PubMed1983

[Electrophysiologic determination of 3 intranodal pathways using various time intervals].

Programmed electrical stimulation of the heart was performed in a 40-year-old man with documented recurrent, sustained ventricular tachycardia, which had proved refractory to standard medical therapy. In this patient, both the presence of several discontinuities in the atrioventricular (AV-)nodal conduction curves during atrial and ventricular stimulation and the varying time intervals of the AV-nodal echo phenomena suggested the presence of multiple AV-nodal pathways.

Adult↗
PubMed1982

Inter- and intraatrial dissociation during spontaneous atrial flutter: evidence for a focal origin of the arrhythmia.

Programmed electrical stimulation of the heart was performed in 2 patients with spontaneous atrial flutter. Patient 1 was a young man with paroxysmal atrial flutter that had proved resistant to drug therapy and who was studied during an episode of sustained flutter. In this patient rapid atrial pacing from the coronary sinus at a critical rate faster than the intrinsic flutter rate provoked local atrial fibrillation in the mid and low right atrium which persisted after termination of pacing. In spite of persistent local fibrillation in these regions, atrial flutter continued in the left atrium and the high right atrium. A second burst of pacing resulted in restoration of sinus rhythm. Patient 2 was an elderly woman with probable sick sinus syndrome who developed spontaneous atrial flutter during the course of an electrophysiologic investigation. During flutter intracavitary recordings from multiple sites in the atria revealed a pattern of 3:2 Wenckebach conduction between the left atrium and the high right atrium, with block of every third atrial depolarization at the latter site. These results indicate that atrial flutter may exist at some sites in the atria which are functionally dissociated from the remainder of the atrial tissue, thus supporting the hypothesis that flutter in some patients may be focal in origin.

Adult↗
PubMed1981

Initiation of ventricular tachycardia by interpolated ventricular premature depolarizations.

Programmed electrical stimulation of the heart was performed in a 47 year old man with prior myocardial infarction and recurrent sustained ventricular tachycardia that was refractory to standard medical therapy. The tachycardia could be provoked by regular atrial pacing at a rate of 100/min, regular ventricular pacing at the same rate and regular atrial pacing at a rate of 200/min in the presence of 2:1 atrioventricular block. All three techniques resulted in an interval of approximately 600 ms between successive ventricular depolarizations. Single interpolated ventricular premature depolarizations delivered during sinus rhythm were followed by a postextrasystolic conducted sinus beat that initiated ventricular tachycardia. However, when the same interpolated ventricular premature depolarization was followed by a ventricular fusion beat no tachycardia ensued. This study therefore emphasizes the importance of hart rate and pattern of ventricular activation in determining whether ventricular tachycardia can be provoked by programmed electrical stimulation of the heart.

Amiodarone↗
PubMed1980

[Prazosin long-term treatment in severe chronic cardiac failure (author's transl)].

In addition to digitalis and diuretics, 10 patients with chronic cardiac failure were treated with prazosin (15 mg/d) over a period of 6 months. It was shown that the mean pulmonary artery pressure decreased significantly, on average by 30%, during both rest and exercise. Despite significant decrease of arterio-central venous oxygen difference no improvement of cardiac output was measured after 6 months on prazosin. Cardiac output increased clearly in only 4 patients, particularly during exercise. Heart rate and arterial blood pressure remained statistically unchanged. Eight patients reported subjective improvement of dyspnoea after 6 months. Prazosin plasma levels were between 9.4 and 58.6 ng/ml. Side effects such as orthostatic hypotension, urinary incontinence and disturbances of potency occurred in 4 patients. Antinuclear factors could not be demonstrated after 6 months. These data show that after 6 months of prazosin therapy haemodynamically significant improvement of pulmonary congestion can be demonstrated without concurrent increase of cardiac output. Prazosin is indicated in treatment of chronic cardiac insufficiency with predominant pulmonary congestion an an adjunct to digitalis and diuretic baseline treatment.

Adult↗
PubMed1980

[Non-invasive method for recognition of coronary artery spasm: 201thallium sequential scintigraphy of the myocardium after ergotamine provocation (author's transl)].

For evaluation of coronary artery spasm 201thallium sequential scintigraphy of the myocardium after ergotamine provocation was performed in 10 patients with recurrent angina pectoris at rest and normal exercise ECG. In 9 out of the 10 patients ergotamine administration in the same dosage was repeated during the coronary angiography. A reversible defect in the 201thallium scintigram representative of regional myocardial ischaemia developed in 9 patients after ergotamine. Only in 4 out of the 9 patients angina pectoris and ST elevation were present at the same time. In all cases coronary spasm after ergotamine was demonstrable in the coronary angiogram; in the 4 patients with ergotamine-induced Prinzmetal angina pectoris it consisted of complete vascular occlusion, in the asymptomatic patients of incomplete vascular narrowing of a higher degree. In all cases the spasm could be relieved by ergotamine antidotes within a few minutes.

Adult↗