Biomedical subjects
Publications and source records attributed to L Kappenberger.
The indication and result of catheter ablation for supraventricular and ventricular arrhythmias are reviewed, with special emphasis on the need to inform the patient undergoing this type of procedure, the possible complications and our center's results.
Infectious complications, a major cause of morbidity and mortality after heart transplantation, were reviewed in 49 heart transplant patients at Lausanne. The follow-up lasted 32 months on average. 43 patients (88%) presented 108 infections (2.20 episodes of infection/patient). 38 severe infections (0.78 episodes/patient) were diagnosed in 27 patients (55%). 2 of the 9 deaths which occurred were due to infection. The viruses, principally of the herpes group, were responsible for 37% of all the infections, and bacteria for 28%. About a third of the viral and bacterial infections were severe. The other documented infections were caused by fungi (13%), which were most often responsible for superficial infections, and rarely by protozoa (5%). Finally, in 17% of infectious episodes, the pathogen could not be identified. Cytomegalovirus was the pathogen the most frequently responsible in severe infections. The highest incidence of infections occurred during the first 2-3 months after transplantation and was reduced considerably after the 6th month. The distribution of different pathogens was related to specific periods after the transplant. Our results confirm that infection is a major complication of heart transplantation. Clinical and prophylactic aspects of some infections are reviewed.
The purpose of this study was to evaluate longterm mortality in 44 patients undergoing electrophysiologically guided therapy for sustained monomorphic ventricular tachycardia. We applied the following modified response criteria: non-inducibility or slowing of induced ventricular tachycardia to < or = 150 bpm. On this basis, 25/44 (57%) patients were classified as responders, and 19/44 (43%) as non-responders. Responders had palpitations significantly more often as the leading clinical sign (68% vs. 21%, p < 0.05). Non-responders showed a lower mean ejection fraction (36 +/- 15% vs. 46 +/- 17%, p < 0.05) and a trend to higher incidence of syncopal ventricular tachycardia (58% vs. 12%, p = 0.15). All responders and 3/19 non-responders continued on drug therapy. 11 non-responders received an implantable cardioverter-defibrillator (ICD), 3 underwent surgery and 2 catheter ablation. 14/44 patients (32%) died during a mean follow-up of 3.2 years. Sudden arrhythmic death occurred in 3/28 patients on drug therapy (1/25 responders, 2/3 non-responders), and in 2/16 non-responders with invasive therapy (one with an ICD and one after catheter ablation). The cumulative all-cause mortality at 3 years was similar in both groups (26% vs 22%, n.s.), but the mortality from sudden arrhythmic death showed a trend to be lower in the responder-group (0% vs 17%, p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)
Coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) are more effective than medical treatment for the management of ischaemic heart disease. However, patients with single-vessel involvement have been excluded from prospective comparisons of the two methods. We have carried out such a comparison in patients with isolated proximal left anterior descending artery stenosis, conserved left ventricular function, and documented ischaemia. Eligible patients presenting to a single centre were randomly assigned PTCA (68 patients) or left internal mammary grafting (66). The procedures were technically feasible in all cases. The incidence of in-hospital complications was 2% (perioperative myocardial infarction) for CABG and 3% (emergency CABG for acute closure) for PTCA. Clinical and functional status improved similarly in both groups. However, patients in the PTCA group took more antianginal drugs. At median follow-up of 2.5 years, 86% of CABG-treated and 43% of PTCA-treated patients were free from adverse events (p < 0.01; relative risk 2.0 [95% CI 1.7-2.3]). The adverse events that explain this difference were restenosis (32%) requiring subsequent surgical (16%) or percutaneous (15%) revascularisation (1% had medical therapy). Rates of cardiac death and myocardial infarction did not differ between the groups. Both CABG and PTCA improve the clinical status of symptomatic patients with single-vessel coronary artery disease. If patient and physician accept the risk of restenosis and reintervention associated with PTCA, this procedure remains a suitable option and a simpler initial alternative to CABG.
This report demonstrates two specific complications that occurred during implantation of a Wiktor (Medtronic, Inc., Minneapolis, MN) coronary stent: stent shortening and elongation were observed and attributed to the unique coil structure of the device. Major cardiac events occurred during follow-up as a consequence of this stent deformation. Therefore, semiurgent bypass surgery should be considered to treat this complication.
From April 1986 through April 1993, 58 intracoronary stents (41 Wall and 17 Wiktor stents) were implanted for the treatment of saphenous vein graft stenosis in 40 symptomatic patients. The indication was a primary stenosis in 44 and restenosis in 14 procedures. In-hospital complications were subacute stent thrombosis (2%), myocardial infarction (2%), and emergency coronary artery bypass grafting (CABG) (2%). Complications during a mean follow-up period of 42+/-27 months were restenosis (35% by patient, 33% by lesion), myocardial infarction (12%), late bypass grafting (12%), and death (7%). On quantitative coronary angiographic analysis, the mean minimal luminal diameter (and its confidence interval) increased from 1.3 mm (1.1-1.5 mm, preprocedure) to 2.9 mm (2.7-3.1 mm, postprocedure) and 2.2 mm (2.0-2.5 mm, 6 months follow-up, 95% angiographic follow-up). Progression of the underlying coronary artery disease and restenosis were the main reasons for a continual decline of the proportion without cardiac event on a Kaplan-Meier estimate. Restenosis occurred in one-third of cases beyond the first 6 months of follow-up. A relative risk ratio analysis for restenosis, performed on 14 variables, disclosed an increased risk for the following variables: (1) stenting of the proximal, distal or anastomosis part of the vein graft (relative risk 2.41, confidence interval: 1.28-3.59), (2) the implantation of stents < 4.5 mm (2.59, 1.18-4.00), and (3) stenting of a redo-CABG vein graft (2.37, 1.17-3.58). Saphenous vein graft stenting seems to be characterized by excellent immediate clinical and angiographic results; in particular, stent thrombosis is rare.(ABSTRACT TRUNCATED AT 250 WORDS)
From April 1986 through April 1992, 123 patients received 153 intracoronary stents (131 Medinvent, 13 Palmaz-Schatz, 9 Wiktor) during 131 procedures. The indication was bail-out treatment in 39, restenosis in 59 native coronary arteries, and stenosis or restenosis in 33 vein grafts. Stent-related events were studied during the in-hospital stay and on follow-up and included closure, stent restenosis, myocardial infarction, death, and the need for coronary bypass surgery. A Kaplan-Meier estimate extended to 6 years showed different short- and long-term outcomes for the distinct treatment groups (p < 0.05): right coronary artery stenting (more particularly, stenting for restenosis after angioplasty) had the lowest and vein graft stenting had the highest stent-related complication rate. The complication rate was similar (p > 0.25) (1) in the case of multiple nontandem stent implantation during the same procedure; (2) for the different endoprosthesis sizes; and (3) during the different procedural years. In native coronary arteries, restenosis after angioplasty of the right coronary artery could be a preferential indication for coronary artery stenting. Despite a favorable short-term outcome, vein graft stenting has a high incidence of events on long-term follow-up, mainly because of late restenosis. Multiple nontandem stenting during the same procedure is not associated with a higher incidence of complications, in particular, the restenosis rate is not appreciably higher. Finally, only a minor benefit for the learning curve is apparent from this single-center experience with continual unchanged postprocedural management.
Assuming that type I atrial flutter is a macroreentrant circuit, its cycle length should vary with the atrial dimensions. In order to test this hypothesis, flutter cycle length was measured while inducing atrial volume and pressure changes by postural and pharmacological means in seven patients undergoing a therapeutic programmed stimulation for type I atrial flutter conversion. Right atrial volume was estimated from B-mode echocardiography data. Basal values were compared with those obtained during inspiration, expiration, Valsalva maneuver, negative tilt (head down), and positive tilt (head up) with 0.8-1.6 mg p.o. nitroglycerin. The right atrial size increased slightly from 17.8 to 18.3 cm2 (P = 0.04) during the pressure load induced by negative tilt (+3 mmHg), with a corresponding lengthening of the flutter cycle length from 228 to 233 msec (P = 0.02). Similarly, pressure unloading of -2 mmHg by positive tilting and nitrates was accompanied by a decrease in right atrial size to 16.6 cm2 (P = 0.04), with a corresponding decrease in cycle length from 228 to 219 msec (P = 0.03). Respiratory maneuver yielded similar results with an inspiratory cycle lengthening, expiratory shortening, and further shortening during Valsalva maneuver. These experiments demonstrate a direct relation between cycle length and atrial volume in human type I atrial flutter. They underline the importance of the right heart preload and atrial size for the electrophysiological characteristics of type I atrial flutter. Beside its fundamental interest, this finding is important for the understanding of the mechanism of maintenance and therapeutic responses of this common arrhythmia.
In this prospective study, the autonomic modulation of the sinus node of 12 patients (mean age 28 +/- 7 years) suffering from vasovagal syncope (VVS) was compared to that of 11 sex and age matched control patients (mean age 32 +/- 4 years) by analysis of heart rate variability. Spectral indices (low frequency power [Plf], high frequency power [Phf], total power [Pt], sympathovagal balance [LF/HF]) and temporal indices, the mean of all coupling intervals between normal beats (mRR), the standard deviation about the mean (sdRR), the percentage of adjacent R to R intervals differing by more than 50 msec (pNN50), and the root mean square of variations in successive R to R intervals (rMSSD) were compared at baseline and during head-up tilt between and within groups. Baseline results were similar in both groups. During tilt testing, comparison of results between groups revealed only significantly higher sdRR and rMSSD and lower LF/HF ratio in VVS patients. Within VVS patients, comparison of temporal and spectral analysis between baseline and tilt showed a significant increase of most indices (Plf, Phf, Pt, sdRR, and rMSSD) but a comparable LF/HF ratio; in contrast, control patients exhibited only a significant increase of LF/HF ratio. In conclusion, VVS patients who developed vasovagal syncope during head-up tilt demonstrated a nonreciprocal modulation of the sinus node by the autonomic nervous system indicative of a pronounced physiological sympathetic surge along with a paradoxical vagal input to the cardiovascular system.
The safety and efficacy of percutaneous transluminal coronary angioplasty (PTCA) was examined in a group of 91 octogenarians during 133 consecutive procedures and compared to the younger part of our PTCA population (3,443 procedures) during an 8-year study period. Most octogenarians presented with refractory or unstable angina pectoris and multivessel involvement, but had normal left ventricular function. The angiographic success rate was 84%. Technical failure was observed in 12% of cases and complications in 14%. Two early procedure related deaths were observed. Restenosis was estimated at 24%. The proportion surviving and the proportion without cardiac event estimated by the Kaplan-Meier method at 2 years were 0.89 and 0.60, respectively. In comparison to the younger population, the immediate angiographic success was lower as a result of a higher incidence of technical failure (P less than 0.05). Otherwise, no difference in terms of restenosis or overall related complication rate was noted (P greater than 0.1). It is concluded that PTCA is an efficient and safe therapeutic option for octogenarians with severe or refractory angina pectoris. Technical failure is more frequently observed than in younger patients and explains a lower immediate angiographic success. Nevertheless, at 2-years follow-up, a large majority of patients are alive and asymptomatic.
The authors report the case of a 36 year old man who presented with an early recurrence of primary ventricular fibrillation. The initial investigations were normal apart from the finding of complete right bundle branch block with persistent ST segment elevation in the right precordial leads. The recurrence was observed 6 weeks after the initial diagnosis which led to the implantation of an automatic defibrillator. This clinical case is similar to a syndrome recently described of sudden death without obvious cardiac disease but with right bundle branch block and ST segment elevation.
Up until recently, the first-line treatment of obstructive hypertrophic cardiomyopathy was pharmacological and surgical in refractory cases. However, the immediate beneficial effect of a cardiac pacing on infra-aortic obstruction has been known for many years. The development of sophisticated two-chamber pacemakers and their use in patients with obstructive hypertrophic cardiomyopathy has confirmed their beneficial effect both in terms of haemodynamic and clinical parameters. There appears to be many reasons for this advantageous effect and only some of them have been elucidated, including alteration of the activation sequence of the left ventricle secondary to apical ectopic electrical activation and reduction of the contact time of the mitral valve with the proximal septum and, in the long term, ventricular remodelling secondary to release of the outflow obstruction. The increasing number of publications reporting a beneficial effect of two-chamber pacemakers in these patients justifies consideration of this approach in all patients refractory to drug therapy.
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The relationship of serum lipoprotein(a) [Lp(a)] to ischemic heart disease was investigated in a series of 114 men undergoing elective diagnostic coronary angiography at the University Hospital of Lausanne (Switzerland). Serum Lp(a) was higher (median: 134 mg/l; mean +/- SD: 371 +/- 509 mg/l) in the 76 individuals with ischemic heart disease, as defined by at least one significant stenosis (> or = 50%) in a proximal segment of a major coronary artery, compared to the 38 individuals without significant stenosis (60 mg/l; 155 +/- 218 mg/l). The risk ratio for ischemic heart disease was 4.2 (95% CI: 1.05-16.6) for serum Lp(a) greater than 300 mg/l compared to concentrations smaller than 50 mg/l, after adjustment for total cholesterol, HDL-cholesterol, body mass index, cigarette smoking, hypertension, and age. Lp(a) was the strongest lipid correlate of a severity score for coronary atherosclerosis (Jenkins' score) after adjustment for the other considered risk factors (partial R squared = 0.10; p < 0.001). These data are consistent with a strong independent effect of Lp(a) on ischemic heart disease. The literature on Lp(a) is reviewed and a clinical approach proposed.
The efficacy of adenosine triphosphate (ATP) was tested in 23 patients suffering from supraventricular tachycardia; 10 patients had orthodromic circus movement tachycardia and 13 typical av nodal reentrant tachycardia. At a mean dose of 0.18 mg/kg all tachycardias were halted in less than 1 minute due to transient acute av nodal block followed by return to normal av conduction within 8 seconds. All patients had transient minor side effects. One elderly subject had a short episode of atrial fibrillation after the acute av block. In conclusion, ATP is useful and safe for rapid termination of supraventricular tachycardias incorporating the av node in their circuit.
Interventional arrhythmology deals with the nonpharmacological management of patients with symptomatic arrhythmias. Percutaneous catheter ablation is used to cure patients with arrhythmias due to accessory pathways or AV-node reentrant tachycardia. In patients with drug-refractory sustained, hemodynamically significant ventricular tachyarrhythmias, implantable third generation defibrillators provide an effective therapeutic modality. Our article provides a brief overview of these new therapeutic modalities and summarizes our local experience.
This paper presents our initial experience with a new low-profile balloon "on-a-wire" catheter, the Bijou. The concept of this balloon is to provide an additional side lumen with the advantages of (1) the ability to measure pressure gradient, (2) the possibility of drug infusion, and (3) the ability to advance a steerable guidewire through this side lumen. The balloon has been tested in 15 patients; 14 underwent an elective procedure for stable angina pectoris (with 2 cases of restenosis) and one an emergency angioplasty in a case of acute myocardial infarction. The stenosis was located on the left anterior descending artery in 11 procedures, on the right in 3, on a marginal branch in 2, on the circumflex and a saphenous vein graft in 1. All stenoses could be dilated successfully (residual stenosis < 25%). The transstenotic pressure gradient felt from 49 +/- 13 mmHg to 7 +/- 4 mm Hg after angioplasty. Except for an uncomplicated dissection in 3 patients, no other complication was noted. With this new catheter, the double-lumen configuration adds the advantages of an "over-the-wire" to an "on-a-wire" system.
Two brothers, 10 and 9 years old, are reported who were treated for years with antiepileptic drugs until the cardiac origin of their syncopal attacks was discovered. Our findings are consistent with the diagnosis of long QT syndrome, although no other family members are affected and only intermittent and mostly borderline QT prolongation could be found. Diagnostic difficulties and genetic implications are discussed.