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J Krafchek

Publications and source records attributed to J Krafchek.

13 recordsLinked to original sources
PubMed1988

Significant variability in the mode of ventricular tachycardia induction and its implications for interpretation of acute drug testing.

Fifty-four patients with previous myocardial infarction and sustained ventricular tachycardia on fibrillation underwent two electrophysiologic studies in the drug-free state within 72 hours. Although the concordance of overall ventricular tachycardia induction over the 2 days was good (87% of patients), there was variability in the number of extrastimuli needed to induce sustained ventricular tachycardia on each day in 60% of patients. Of those in whom ventricular tachycardia was inducible on both days, 40% required additional extrastimuli and 20% required fewer extrastimuli. A change by two or more extrastimuli was found in 12% of patients. There was no correlation between the variability observed and multiple clinical and laboratory parameters (including the aggressiveness of the stimulation protocol); however, the direction of the variability (easier or harder to induce) correlated with changes in ventricular refractoriness. Inherent day-to-day variability may affect the reproducibility of electrophysiologic studies and influence the results of serial drug testing.

Adult↗
PubMed1988

Amiodarone pulmonary toxicity: prospective evaluation of serial pulmonary function tests.

Pulmonary toxicity developed in 15 (17%) of 89 patients treated with amiodarone during a follow-up period of 2 weeks to 54 (mean 20 +/- 15) months. Prospective evaluation of serial pulmonary function tests in 67 patients demonstrated both a significant decrease from baseline in three of six variables in patients with toxicity at the time of diagnosis and a significant difference compared with the same variables in patients without toxicity. The most significant of these was the diffusing capacity for carbon monoxide (DLCO). An individual decrease in DLCO greater than or equal to 15% gave an optimal sensitivity of 100% and a specificity of 89% for the diagnosis of pulmonary toxicity. However, a decrease in DLCO greater than or equal to 15% did not alone warrant a change in therapy in asymptomatic patients. Although higher maintenance doses of amiodarone appeared to be related to the development of this complication, an abnormal baseline DLCO (less than 60% of predicted) with or without an initial abnormal chest roentgenogram did not predispose to pulmonary toxicity.

Aged↗
PubMed1988

Cumulative effects of amiodarone on inducibility of ventricular tachycardia: implications for electrophysiological testing.

To determine whether the slow onset of action of amiodarone might result in a delayed effect on the inducibility of sustained ventricular arrhythmias, 45 patients with ischemic heart disease and inducible sustained monomorphic ventricular tachycardia were prospectively studied. Each patient had at least one initial repeat study on amiodarone and those with persistently inducible arrhythmias were rescheduled for further studies over the following 24 weeks. After 2-3 weeks of amiodarone therapy, nine patients no longer had inducible tachycardias, and tachycardia in another eight patients (18%) later became noninducible. Using life-table methods, analysis based on the results of the first re-study showed 18-month recurrence rates of 43% in the inducible vs 17% in the noninducible groups (p = 0.056). When the results of additional testing were then used to reclassify patients, the recurrence rates for these two groups were 50% and 17%, respectively (p = 0.004). Observation of blood pressure and level of consciousness during induced arrhythmias was also predictive of clinical tolerance in patients having recurrences; 16 of 19 patients experienced symptoms of similar severity to those produced during testing. We conclude: (1) early testing of amiodarone may result in misclassification of some patients as remaining inducible; (2) re-testing at a later time more accurately predicts tachycardia recurrence; (3) observation of hemodynamic response also provides important prognostic information.

Adult↗
PubMed1987

Prospective comparison of right and left ventricular stimulation for induction of sustained ventricular tachycardia.

Thirty-eight patients who had sustained monomorphic ventricular tachycardia (VT) or sudden cardiac death underwent programmed ventricular stimulation. To assess the relative efficacy of right and left ventricular (RV and LV) stimulation, a tandem protocol with 1 to 4 extrastimuli and burst pacing was used. Each step of the protocol was performed in a rotating sequence at the RV apex, basal RV septum and LV apex. Sustained VT was induced from the RV apex in 26 patients, right ventricle (either site) in 27, and LV apex in 24, and spontaneous VT was reproduced from those sites in 11, 14 and 12 patients, respectively. In the 23 patients who had sustained VT induced from both ventricles, RV stimulation always required fewer or the same number of extrastimuli for induction. At every stage of the protocol, the cumulative yield of sustained VT was consistently greater from the right ventricle than from the left ventricle. After delivering 4 extrastimuli and burst pacing, LV stimulation only increased the yield of sustained VT by 1 patient, and spontaneous VT by 3 patients. Inducibility or noninducibility in the right ventricle generally predicted the same outcome in the left ventricle. Previously undocumented VT or ventricular fibrillation was induced from the right ventricle in 19 patients and from the left ventricle in 13. Thus, LV stimulation was less efficacious than RV stimulation. LV stimulation increased the yield over RV stimulation only minimally and did not reduce the number of extrastimuli required to induce sustained VT.

Cardiac Catheterization↗
PubMed1987

Two different patterns of entrainment of ventricular tachycardia.

In a patient with two morphologic forms of ventricular tachycardia, rapid pacing from different ventricular sites produced two distinctively different patterns of entrainment. Pacing from sites contralateral to the site of emergence of ventricular tachycardia caused progressive fusion. Following pacing, the interval (return interval) between the first tachycardia beat (return beat) and the preceding beat was equal to the pacing cycle length. Near the site of emergence, the local electrogram of the return beat was morphologically identical to that of the preceding paced beats. In contrast, pacing from sites ipsilateral to the site of emergence did not cause fusion. The return intervals increased with decreasing pacing cycle lengths. The local electrogram of the return beat was morphologically different from that of the preceding paced beats. Using a model of ventricular reentrance, both patterns of responses can be explained. Pacing impulses arising from sites contralateral to the site of emergence activate the latter orthodromically. Fusion occurs between the emerging tachycardia wavefront and the next pacing wavefront. In contrast, pacing impulses arising from sites ipsilateral to the site of emergence activate the latter antidromically. Fusion is not observed because collision within the area of slow conduction prevents the emergence of the tachycardia during pacing.

Adult↗
PubMed1986

Classic and concealed entrainment of typical and atypical atrial flutter.

Classic and concealed entrainment was demonstrated in a patient with spontaneous typical atrial flutter and pacing-induced atypical atrial flutter. The form of entrainment manifested depended on the site of pacing and the direction of tachycardia as determined by endocardial mapping.

Atrial Flutter↗
PubMed1986

Surgical ablation of ventricular tachycardia: improved results with a map-directed regional approach.

To determine whether a regional approach to surgery for ventricular tachycardia would improve on the results of previously reported methods of endocardial resection, an analysis was performed of our surgical experience over a 5 year period. Of 46 consecutive patients operated on for recurrent sustained ventricular tachycardia or ventricular fibrillation, 39 patients with ischemic heart disease underwent subendocardial resection and/or cryoablation. The mean age of the patients was 61 +/- 8 (SD) years, the mean left ventricular ejection fraction was 32 +/- 11%, and the mean number of ineffective antiarrhythmic drugs was 3.8 +/- 1.2 per patient. In 35 of 39 patients in whom mapping data were obtainable, 56 (86%) tachycardias had earliest sites of activation in the left ventricle and nine (14%) had earliest sites in the right ventricle. Ten patients had 14 tachycardias (21%) mapped to areas outside visible dense scar. Of these 35 patients, 10 underwent localized subendocardial resection and 25 underwent a regional procedure in which all areas activated before the surface QRS during ventricular tachycardia were excised and/or cryoablated. In the operative survivors of electrophysiologically guided surgery, three of eight (38%) patients with the localized and one of 24 (4%) patients who underwent the regional procedure had recurrence of ventricular tachycardia during a follow-up period of 1 to 59 (mean 22 +/- 17) months (p = .04). The favorable outcome of regional surgery was not influenced by the presence of multiple morphologies in 54%, disparate sites of origin in 29%, or inferior wall foci in 46% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Cryoablation of arrhythmias from the interventricular septum: initial experience with a new biventricular approach.

The use of cryothermy in addition to other newer surgical techniques has improved the outcome for patients undergoing operation for ventricular tachycardia. However, the depth to which the cryothermic lesions penetrate the myocardium may be a limiting factor in some situations. In an attempt to overcome this problem, we applied cryothermia from both sides using a new biventricular approach in five patients with documented interventricular septal foci. The advantages, disadvantages, and possible indications for the use of this approach are discussed, as are methods for avoiding potential complications.

Adolescent↗
PubMed1985

Progress in the surgical treatment of cardiac arrhythmias. Initial experience of 90 patients.

Between 1981 and 1985, ninety patients were treated surgically for cardiac arrhythmias and have been followed for a mean interval of 21 months (range, one to 49 months). Follow-up is 100% complete. Fifty accessory pathways were divided in 35 patients (25 male and ten female; mean age, 35.2 years; range, 10 to 72 years), with no deaths. Five females, aged 10 to 35 years, were treated for focal atrial tachycardia, three for an atrial focus alone, and two with other arrhythmia procedures; four were cured and one was improved. Two patients (one man and one woman, both aged 33 years) had ablation of the atrioventricular node. Forty-one patients (32 male and nine female; average age, 56.9 years; range, 15 to 74 years) had ablation of ventricular tachycardia. Kent bundle division and focal atrial tachycardia ablation were also performed in two of these patients. More than 80% of patients had coronary disease. Mean preoperative ejection fraction was 33.9% with a range of 14% to 65%. Aneurysmectomy, endocardial resection, cryoablation, and coronary artery bypass were the procedures used. The perioperative mortality rate was 9.8% but there were no deaths in the last 23 patients. Ventricular tachycardia was abolished in all but three survivors in whom medical treatment is now effective. The automatic implantable defibrillator was implanted in 11 patients, with no surgical deaths. These results confirm the feasibility of relieving a variety of serious arrhythmias by surgical intervention.

Adolescent↗
PubMed1985

A reconsideration of Doppler assessed gradients in suspected aortic stenosis.

To further define the clinical role of continuous wave Doppler echocardiography for determining aortic valve gradient, we studied 60 consecutive adult patients (age range 22 to 81 years, mean age 63) with suspected aortic stenosis within 24 hours of catheterization. Blind comparisons of Doppler peak and mean gradients by the simplified Bernoulli equation were made with catheterization peak-to-peak (r = 0.84), peak (r = 0.87) and mean (r = 0.84) gradients in a double-blind fashion. Despite these favorable correlations, Doppler peak gradient generally overestimated catheterization peak-to-peak gradient (1 to 53 mm Hg), making it impractical for clinical use. Doppler-catheterization correlations of peak and mean gradients were more favorable, with the least scatter noticed for mean gradient. The results of analysis of pooled data indicated that mean gradient may also be most specific for differentiating severe from less severe aortic stenosis. In this consecutive series where a full range of catheterization gradients was encountered, seven patients with predicted Doppler gradients were found to have none, which is best explained by the use of the simplified Bernoulli equation in patients with aortic insufficiency. These data indicate that prudence should be maintained when Doppler gradients alone are used for the assessment of aortic stenosis.

Adult↗
PubMed1984

Prognosis of cardiac disease in the ambulant patient.

Much investigation and treatment in cardiac practice is based on the assumption that unexpected death is common in cardiac patients. The validity of this assumption was examined in 636 of 669 (95.1%) consecutive ambulant patients. During the period from 1978 to 1981, inclusive, 16 (3.9%) of the 407 men (median age, 52 years) and six (2.6%) of the 229 women (median age, 54 years) died. Nineteen of these 22 patients died of cardiac causes; most of these were elderly (average age, 68.5 years), had advanced cardiac disease for many years before their death, and complained of breathlessness at the initial interview. None of these deaths was unexpected. It is concluded that unexpected death is relatively uncommon, even in cardiology practice. The intensive diagnostic and therapeutic regimens directed at younger patients with cardiomyopathy and coronary disease who do not complain of breathlessness are unlikely to have an appreciable impact on mortality.

Adult↗
PubMed1981

Protamine sulphate hypersensitivity.

Protamine hypersensitivity has been documented by intra-dermal skin testing in three patients who demonstrated sudden cardiovascular collapse and bronchospasm following the use of intravenous protamine sulphate. All patients had been given protamine previously. The effects of the anaphylactic response were terminated quickly by the administration of intravenous adrenaline associated with plasma volume expansion. Intra-dermal skin testing against all anaesthetic agents is recommended so that the specific allergen can be identified. In patients who are shown to be allergic to protamine sulphate and who require cardiac or vascular surgery careful monitoring of heparin dosage and neutralisation with hexadimethrine (Polybrene) intravenously appears to be a safe alternative.

Anaphylaxis↗