Levo-alpha-acetylmethadol (LAAM) induced QTc-prolongation - results from a controlled clinical trial

BACKGROUND

Due to potential proarrhythmic side-effects levo-alpha-Acetylmethadol (LAAM) is currently not available in EU countries as maintenance drug in the treatment of opiate addiction. However, recent studies and meta-analyses underline the clinical advantages of LAAM with respect to the reduction of heroin use. Thus a reappraisal of LAAM has been demanded. The aim of the present study was to evaluate the relative impact of LAAM on QTc-interval, as a measure of pro-arrhythmic risk, in comparison to methadone, the current standard in substitution therapy.

METHODS

ECG recordings were analysed within a randomized, controlled clinical trial evaluating the efficacy and tolerability of maintenance treatment with LAAM compared with racemic methadone. Recordings were done at two points: 1) during a run-in period with all patients on methadone and 2) 24 weeks after randomisation into methadone or LAAM treatment group. These ECG recordings were analysed with respect to QTc-values and QTc-dispersion. Mean values as well as individual changes compared to baseline parameters were evaluated. QTc-intervals were classified according to CPMP-guidelines.

RESULTS

Complete ECG data sets could be obtained in 53 patients (31 LAAM-group, 22 methadone-group). No clinical cardiac complications were observed in either group. After 24 weeks, patients receiving LAAM showed a significant increase in QTc-interval (0.409s +/- 0.022s versus 0.418s +/- 0.028s, p = 0.046), whereas no significant changes could be observed in patients remaining on methadone. There was no statistically significant change in QTc-dispersion in either group. More patients with borderline prolonged and prolonged QTc-intervals were observed in the LAAM than in the methadone treatment group (n = 7 vs. n = 1; p = 0.1).

CONCLUSIONS

In this controlled trial LAAM induced QTc-prolongation in a higher degree than methadone. Given reports of severe arrhythmic events, careful ECG-monitoring is recommended under LAAM medication.

[Automatic external defibrillator--mode of operation and clinical use]

Every year about 100,000 persons die from sudden cardiac death (SCD) in Germany. Although many efforts have been undertaken, mortality remains high. Only 2 - 10% of patients with out-off hospital SCD can finally be discharged from hospital after resuscitation. Observational studies show that ventricular fibrillation and ventricular tachycardia are the primary arrhythmias underlying SCD. For both arrhythmias the main determinant for survival is the time between onset and termination by defibrillation. The chance of survival declines by 10% for every minute of delay. These findings prompted the concept of early defibrillation by first responders. Many studies have shown that non-medical professionals, like police men, firemen or security officers, often arrive at the patient more early than emergency medical service. Thus, "smart" automated external defibrillators (AEDs), designed to identify VT/VF and prompt the user when to deliver a shock were introduced. These devices allow lay rescuers to terminate ventricular arrhythmias before the arrival of medical professionals. By this approach the time to defibrillation could be reduced and a significant reduction in mortality could be documented in selected situation. These encouraging results initialled the installation of AED at public places like aircrafts, airports, underground stations and shopping males. Due to the success of this approach doctors are more and more confronted with questions about technical details, reliability and cost effectiveness of these devices. The present review should give an overview about the current studies and guidelines.

Gadolinium as an Alternative Contrast Agent During Cardiac Catheterization in Patient with Iodine-induced Hyperthyroidism

We report the first case of a male patient with iodine-induced hyperthyroidism and unstable angina pectoris in whom a diagnostic cardiac catheterization with gadolinium as contrast agent was chosen. The patient was hospitalized with an iodine-induced hyperthyroidism after angioplasty using an iodinated contrast agent. He presented with a continuous arrhythmia and unstable angina pectoris. A repeated cardiac catheterization using iodinated contrast agent was contraindicated. This case report shows that gadolinium is a useful alternative contrast agent for cardiac intervention in patients with iodine-induced hyperthyroidism.

Dilated cardiomyopathy in two adult human immunodeficiency positive (HIV+) patients possibly related to highly active antiretroviral therapy (HAART)

Human immunodeficiency virus (HIV) and acute immunodeficiency syndrome are known to be associated with cardiac involvement. In this respect, a relation between HIV and dilated cardiomyopathy has been described. Additionally, highly active antiretroviral therapy (HAART) may independently contribute to cardiac impairment. We here report two cases of severely reduced left ventricular function detected in the context of a recent standardized screening of 132 HIV+ individuals of the German heart failure network. Both patients presented in a poor overall condition and progressive exercise-induced dyspnea accompanied by edema or angina pectoris, respectively. Subsequent examinations revealed left bundle-branch blockade, ventricular arrhythmia, elevated serum BNP-levels as well as pathologic transthoracic echocardiography, left ventricular angiography, electron beam tomography and cardiac magnetic resonance imaging without significant coronary stenoses or immunohistological signs of an ongoing or prior myocarditis. Clinical signs of progressive chronic heart failure developed slowly but constantly following initiation of the HAART regimen. Patients were treated by an implantation of a biventricular implantable cardioverter defibrillator beside conventional conservative standard therapy followed by a significant improvement of clinical symptoms. Antiviral medication could be maintained in both patients. Taking all data into account, the diagnosis of a HAART-associated dilated cardiomyopathy could be assessed. Even though the pathogenesis of secondary heart failure after HAART is still object of investigation a mitochondrial impairment by antiviral drugs is thought to contribute the development of dilated cardiomyopathy. However, due to the coexistence of an eminent HIV infection, a direct effect of the HI virus itself can not be completely excluded.

[The Herz Handy--a new telemedical service concept for heart patients]

Telemedicine is a new milestone for the health care system in the care of patients with heart disease. New technologies and the possibilities of fast data transmission have enabled this step forward. The Cardiophone offers a new telemonitoring Service Concept, which is available 24 hours a day. The patient is by the aid of the Cardiophone connected with the Medical Service Center at just the press of a button, can record and transmit an ECG and can be localized by the incorporated GPS. We report about our experiences with 363 patients over 3 years. Out of 5064 patient contacts associated with 7561 calls, 559 emergency contacts occurred. From the initial main complaints, working diagnoses were established. The final confirmed diagnoses were arrhythmias (27.8%), coronary heart disease (25.9%), psychovegetative syndrome (12.7%), backbone pain (6.2%), gastrointestinal syndrome (3.6%), others (1.8%), and exclusion diagnosis (19.9%). Ten myocardial infarctions were diagnosed, of whom 3 were confirmed; the other 7 were treated as stabile angina pectoris. Overall 823 ECG were transmitted, in average 1.6 ECGs per emergency contact. In 131 ECGs changes of the ST-segment or T-wave could be documented; 26 patients showed a pacemaker ECG. Atrial and ventricular arrhythmias as well as conduction disturbances were seen. The majority of emergency contacts (n=477, 85.3%) were successfully managed by the Service Center. In 38 emergency contacts (6.8%) admission to hospital was recommended; in 4 cases (0.7%) an ambulance was activated via the local dispatcher by the Service Center and in 29 cases (5.2%) the emergency ambulance.

Immunohistochemical differentiation of eosinophilic heart diseases using antibodies against eosinophil activation markers

AIMS

Eosinophilic heart syndromes are rare in Western countries and include endocarditis parietalis fibroplastica (EPF) and hypersensitivity myocarditis (HM). There are striking differences in natural history and morphological findings. Since diagnosis can be difficult when analysing small myocardial biopsies lacking the characteristic histological features, we studied a set of immunohistochemical markers in order to characterize the activation status of the infiltrating eosinophils to distinguish between these two entities.

METHODS AND RESULTS

This study is based on the investigation of seven explanted hearts and one left ventricular specimen collected during implantation of a left ventricular assist device from a total of seven patients with HM. Also investigated were three right and three left ventricular specimens from five patients with EPF. We used antibodies (Ab) against EG1, and EG2, CD44, and CD69 which have been described as markers to distinguish between resting and activated eosinophils. The EG1 to EG2 ratio of eosinophils and the immunoreactivity against CD44 showed no differences between the two entities. However, eosinophils in the EPF were completely negative for CD69, whereas eosinophils reacted positively within the HM group.

CONCLUSION

The immunohistochemical investigation of eosinophilic heart diseases using antibodies against CD69 can be a useful tool to distinguish between hypersensitivity myocarditis and endocarditis parietalis fibroplastica.

Media remodeling – the result of stent induced media necrosis and repair

Background: Stents have been introduced clinically to help maintaining the patency of the vascular lumen after balloon angioplasty. To ensure a sufficient lumen of the stented vessel, oversized stents are frequently used. However especially deployment of oversized stents may lead to mechanical injury of the intima and media of the vessel wall. The aim of the study was to characterize the vascular lesions and repair processes within the first 4 weeks after implantation of oversized stents in the rabbit carotid artery and thereby contribute to the understanding of vascular remodeling during stent implantation. Methods: Oversized stents were implanted in the carotid artery of Chinchilla rabbits. Rabbits were sacrificed 3, 7, 14, and 28 days after stent implantation and a detailed histologic and immunohistochemical analysis was performed. Results: The carotid artery was expanded by a factor of 1.3–1.5, leading to a constant dilatation of the vessel. The struts were deeply impressed in the vessel wall, resulting in a disruption of the intima, thrombus formation, media compression and segmental media necrosis. The necrotic media was repopulated by smooth muscle cells by day 7. In contrast to the intima lesions, necrotic areas of the media were not invaded by an inflammatory infiltrate. Formation of neointima, characterized by a confluent layer of endothelial cells and deposition collagen fibers started in close vicinity of the struts. Conclusions: Being part of a high-pressure system, the arterial vessel apparently adapts to constant dilatation. Deployment of oversized stents caused intima disruption, media necrosis of varying degree and constant dilatation of the vessel wall. Necrosis and repopulation of smooth muscle cells of the media took place within the first 4 weeks, leading to the speculation whether the repopulating SMC are more resistant to the constant pressure.

Myocardial perfusion abnormalities in patients with active acromegaly

Cardiomyopathy is often seen in patients with a long history of acromegaly. In order to screen for perfusion abnormalities, patients with active acromegaly without evidence for coronary heart disease were examined by single photon emission computed tomography (SPECT). The study included a group of 11 strictly selected patients with active acromegaly (7 males and 4 females; age 51 +/- 12 y [mean +/- S.D.]) with elevated age-adjusted IGF-I levels (IGF-I 569 +/- 193 micro g/l; GH 31.2 +/- 56.3 micro g/l) compared to an age- and sex-matched non-acromegalic control group with comparable muscle mass index of the left ventricle (126 +/- 41 active vs. 122 +/- 33 g/m 2 control group) and body mass index (26.6 +/- 2.7 vs. 27.0 +/- 5.0 kg/m 2). To address this issue, myocardial perfusion was investigated by single photon emission computed tomography (SPECT) using a triple head gamma-camera. 70 MBq 201TlCl was injected, and post-stress (from bicycle ergometer) images were obtained. Images were interpreted quantitatively by bull's eye polary map (16 regions of the left ventricle) and were compared to the control group. In the patients with active acromegaly, the mean nuclide uptake of the 16 regions of the left ventricle after bicycle stress examination was lower than in the control group (82.99 +/- 2.85 active vs 85.48 +/- 1.29 control group, p < 0.01). Non-homogeneity of nuclide uptake was defined as the standard deviations of the 16 regions and was higher in patients with active acromegaly (11.11 +/- 2.35 active vs. 8.77 +/- 1.39 control group, p < 0.01). In conclusion, myocardial perfusion is impaired in patients with active acromegaly, thus representing an early stage of cardiac involvement in acromegaly that may be directly mediated by growth hormone excess.

[Sinus node dysfunction with intermittent sinus arrest and AV-nodal escape rhythm as initial manifestation of pheochromocytoma]

A 25-year-old male student complained about episodic palpitations, dizziness, nausea and headache 5 years prior to presentation. No otorhinolaryngic, neurologic or gastrointestinal causes were identified. Several ECG recordings revealed sinus node dysfunction with intermittent sinus arrest and AV-nodal escape rhythm. The patient was given a permanent DDD-pacemaker. Six months later, the clinical symptoms were unchanged. During an attack, physical examination revealed paleness, diffuse sweating and an arterial blood pressure of 250/130 mmHg, which decreased to 120/80 mmHg within a few minutes. Abdominal ultrasound and abdominal computed tomographic scan demonstrated the presence of a large (6.4 x 5.5 cm) left-sided adrenal mass. Two 24-h-urinary collections demonstrated elevated noradrenaline (mean 315 micrograms/24 h, normal < 80 micrograms/24 h) and adrenaline (mean 268 micrograms/24 h, normal < 20 mg/24 h) levels. Blood samples, which were drawn during excessive blood pressure rise, revealed elevation of plasma catecholamines (6.793 pg/ml for adrenaline (normal 50-150 pg/ml) and 10.424 pg/ml for noradrenaline (normal 200-500 pg/ml), so that the diagnosis of pheochromocytoma was considered established. The tumor was successfully removed during laparascopic surgery. After surgery, the patient remained well and normotensive. Three months later, several long-term ECG recordings showed sinus arrhythmia with no evidence of sinus arrest or AV-nodal escape rhythm, so that the DDD pacemaker was turned off. This case underlines that sinus node dysfunction with intermittent sinus arrest and AV-nodal escape rhythm is a potential early manifestation of a pheochromocytoma. These changes seem to disappear after successful removal of the tumor.

Increased heterogeneity of coronary perfusion in patients with early coronary atherosclerosis

BACKGROUND

In patients with typical angina but angiographically normal coronary arteries, abnormal vasomotor function is assumed to be a major underlying cause. However, data on this issue are conflicting, and recent studies suggest that fluid dynamic abnormalities exist in these patients. The aim of the study was to evaluate whether early stages of atherosclerosis are characterized by alterations of baseline coronary hemodynamics and endothelium-independent vasomotion. Besides established intracoronary Doppler parameters, heterogeneity of perfusion was assessed and related to early signs of atherosclerosis as determined by electron-beam computed tomography (EBCT).

METHODS

In 59 patients with typical angina and angiographically normal or near-normal coronary arteries, intracoronary Doppler measurements were performed in all 3 major coronary arteries. Baseline average peak velocity (bAPV) and hyperemic average peak velocity (hAPV) in response to intracoronary injection of adenosine were measured, and coronary flow velocity reserve (CFVR) was calculated. Heterogeneity was assessed as variability of bAPV, hAPV, and CFVR and was calculated as (STD/MEAN). 100. Doppler data were analyzed according to tertiles of the EBCT-derived Agatston calcium score (ie, score 0-1 [lowest tertile], 2-28 [medium tertile], and >28 [highest tertile]).

RESULTS

The mean EBCT-derived Agatston calcium score was 49 +/- 107. No coronary calcium was observed in 17 (29%) patients. The mean values of bAPV, hAPV, and CFVR were not different between the calcium score tertiles. However, patients in the highest tertile had a significantly increased variability index of bAPV (29.6% +/- 11.6%) compared with patients in the lowest tertile (13.4% +/- 7.3%, P <.0001). Variability of CFVR was also increased in these patients (15.5% +/- 11.7% vs 10.5% +/- 4.0%, P =.03).

CONCLUSION

These results indicate that early stages of atherosclerosis are characterized by microvascular abnormalities that do not uniformly affect the myocardium but are heterogeneous. The high variability of baseline coronary flow velocity with increasing coronary calcium suggests that in patients with early stages of atherosclerosis fluid dynamic effects may play a crucial role even in the absence of angiographically appreciable epicardial stenoses.

Plaque distribution and vascular remodeling of ruptured and nonruptured coronary plaques in the same vessel: an intravascular ultrasound study in vivo

OBJECTIVES

This study was designed to identify potential differences between the intravascular ultrasound (IVUS) characteristics of spontaneously ruptured and nonruptured coronary plaques.

BACKGROUND

The identification of vulnerable plaques in vivo may allow targeted prevention of acute coronary events and more effective evaluation of novel therapeutic approaches.

METHODS

Intravascular ultrasound was used to identify 29 ruptured plaques in arteries containing another nonruptured plaque in an adjacent segment. Intravascular ultrasound characteristics of these plaques were compared with plaques of computer-matched controls without evidence of plaque rupture. Plaque distribution was assessed by measuring the eccentricity of lumen location (inside the total vessel). Lumen cross-sectional area narrowing was calculated as [1 - (target/reference lumen area)] x 100%. A remodeling index was calculated as lesion/reference arterial area (>1.05 = compensatory enlargement, <0.95 = shrinkage).

RESULTS

Among the three groups of plaques, there was no significant difference in quantitative angiographic parameters, IVUS reference dimensions and IVUS lumen cross-sectional area narrowing. There was a difference in plaque distribution; lumen location by IVUS was significantly more eccentric in ruptured than in nonruptured (p = 0.002) and control plaques (p < 0.0001). The arc of disease-free vessel wall was larger in ruptured than in control plaques (p < 0.0001). The remodeling pattern of ruptured and nonruptured plaques differed significantly from that of the control plaques (p = 0.0001 and 0.003); compensatory enlargement was found in 66%, 48%, and 17%, whereas shrinkage was found in 7%, 10% and 48%, respectively.

CONCLUSIONS

Intravascular ultrasound assessment of plaque distribution and vascular remodeling may help to classify plaques with the highest probability of spontaneous rupture.

Abnormal Coronary Flow Velocity Reserve After Coronary Intervention Is Associated With Cardiac Marker Elevation

Background —Residual reduction of relative coronary flow velocity reserve (rCVR) after successful coronary intervention has been related to microvascular impairment. However, the incidence of cardiac enzyme elevation as a surrogate marker of an underlying embolic myocardial injury in these cases has not been studied.

Methods and Results —A series of 55 consecutive patients with successful coronary stenting, periprocedural intracoronary Doppler analysis, and determination of creatine kinase (CK; upper limit of normal [ULN] for women 70 IU/L, for men 80 IU/L) and cardiac troponin T (cTnT; bedside test, threshold 0.1 ng/mL) before and 6, 12, and 24 hours after intervention were studied. Postprocedural rCVR was the only intracoronary Doppler parameter that independently correlated with cTnT ( r =−0.498, P <0.001) and CK outcome ( r =−0.406, P =0.002). Receiver operating characteristic analysis identified a postprocedural rCVR of 0.78 as the best discriminating value, with a sensitivity of 83.3% and 69.2% and a specificity of 79.1% and 76.2% for detection of cTnT and CK elevation, respectively. Stratified according to this cutoff value, the incidence of cTnT elevation was 52.6% in patients with (n=19) and 5.6% in patients without (n=36) a postprocedural rCVR <0.78 ( P <0.001), associated with a CK elevation >1 times the ULN in 36.8% and 5.6% ( P =0.005) of patients, respectively.

Conclusions —Cardiac marker elevation can frequently be found after coronary procedures that are associated with a persistent reduction of rCVR, indicating procedural embolization of atherothrombotic debris with microvascular impairment and myocardial injury as a potential underlying mechanism.

[Metallic biomaterials for coronary stents]

The introduction of coronary stents is a milestone in interventional cardiology. Two landmark studies have shown that stainless steel stents significantly decrease the restenosis rate as compared to balloon angioplasty. This fact led to a marked increase of stent implantation since the first stent implantation by Jacques Puel in 1986. Although the concept of coronary stenting significantly improved the interventional therapy of coronary artery disease, restenosis remains a major unsolved drawback of this technique. In addition to procedure and disease related factors like implantation pressure and plaque burden, data suggest that the stent as a medical implant plays a crucial role in the process of neointima formation. Since its introduction in cardiology, more than 50 different stents of different configuration and material have been developed. Although recent publications report of promising results using biodegradable materials, almost all coronary stents commercially available at the moment are made of metallic alloys. Whereas first generation stents were made exclusively from stainless steel and only minor interest was focussed on the stent material in the manufacture of coronary stents, recent studies strongly suggest that the metallic alloy used has a direct impact on the extent of neointima formation. Thus, metallic alloys differ not only with respect to mechanical features, but also by their biocompatible properties. These two factors are of major importance in the induction of vessel wall injury, inflammatory processes and cell proliferation. In the first part, the present paper reviews the metallurgic characteristics of metallic materials, which are currently used or under investigation in the production of coronary stents. In the second part, clinical and experimental results are summarized with respect to their biocompatibility and impact on the process of restenosis formation.

[Electron beam computed tomography of the heart before kidney transplantation. Severe coronary disease in a 21-year old woman with nephrocalcinosis due to infantile hypercalcemia syndrome]

BACKGROUND

Cardiovascular diseases are very common in patients with end-stage renal disease and are the underlying cause of approximately half the deaths in dialysis patients. In those patients vascular calcifications are typically seen in the tunica media and therefore represent histopathological changes different to those in atherosclerosis. For the evaluation of cardiovascular risk in chronic dialysis patients, a method is needed to reliably identify patients who have to undergo invasive diagnostics. Coronary artery calcium assessed by electron beam computed tomography (EBT) has been suggested to measure the extent of coronary atherosclerosis in patients with normal renal function. It might also be of value in the stratification of cardiovascular risk in patients with renal failure.

CASE REPORT

We report the case of a 21-year-old female with end-stage renal disease as a result of idiopathic infantile hypercalcemia with nephrocalcinosis and extensive vascular calcification. Due to a total atrioventricular block, a 2-chamber pacemaker had been implanted in 1998. Because of a very high calcium score in EBT, depressed left ventricular function in echocardiography, and limited physical strength she was sent to coronary angiography. Severe 2-vessel coronary artery disease was found and successfully treated by balloon angioplasty. She was then listed for renal transplantation. Angiographic 6-month follow-up showed an excellent long-term result.

CONCLUSION

This case demonstrates that coronary artery disease can also be present in young dialysis patients. Discrimination of atherosclerotic vascular calcification and tunica media sclerosis typical in dialysis patients without hemodynamic effects is difficult. EBT allows for the direct detection of coronary calcium. Its extent correlates with coronary atherosclerosis and the probability of acute coronary syndromes in patients with normal renal function. This evidence has not been proved for dialysis patients, yet. However, EBT may be of value in the stratification of cardiovascular risk for patients awaiting renal transplantation.

[Cardiac resynchronization therapy in terminal heart failure: current status and prospects]

BACKGROUND

With regard to epidemiological aspects, heart failure has been shown an increasing incidence in constrast to coronary artery disease which counts decreasingly due to secondary and primary prevention. The present data show an incidence for heart failure of 2% per year. 4-5 million people are newly affected by the disease. The prognosis is limited after diagnosis is confirmed. According to the US Framingham study, the median life expectancy is 3.2 and 5.4 after diagnosis for male and female, respectively. For patients in an advanced stage of the disease the mortality rate is 27% within 3 years. AV SEQUENTIAL PACING: The introduction of AV sequential pacing by the Austrian group of Margarete Hochleitner in 1992 showed an improved left ventricular systolic function, an improved clinical benefit in terms of NYHA classification, an enhanced left ventricular ejection fraction, an improved systolic and diastolic blood pressure, a reduction of the heart-chest relationship as well as a reduction of the resting hart rate and the echocardiographic dimension parameters.

STUDIES

First experimental approach for biventricular stimulation, which means the simultaneous activation of the right and the left chamber, relied on the observation of a distorted ventricular activation due to the presence of a bundle branch block. The bundle branch block is a result of the dilatation of the myocardial fibers, death of myocardial cells which are replaced by fibrous tissue. Resynchronization of both ventricles was associated with an improved left ventricular function and improved diastolic relaxation. Clinical studies of patients with heart failure, severe left ventricular systolic dysfunction, and left bundle branch block have shown that systolic function can be improved by electrically stimulating the site of late activation. The magnitude of the improvement seems to be associated with the duration of the intrinsic surface QRS complex and whether the ventricle ipsilateral with the conduction defect is stimulated. The effect of ventricular resynchronization therapy was optimized by timing of atrioventricular activation associated with a decrease in both systolic and diastolic mitral regurgitation.

CONCLUSION

The prognosis of patients with end-stage heart failure is limited by two determinants: myocardial pump failure and sudden (arrhythmogenic) cardiac death. Due to the fact that the incidence for sudden cardiac death is considerably high in patients with end-stage heart failure it is reasonable to include the implantation of cardioverters/defibrillaters (ICD) in the concept of biventricular stimulation.

Improved detection and analysis of sensed and paced events in dual chamber pacemakers with extended memory function. A prospective multicenter trial in 626 patients

PATIENTS AND METHODS

This prospective study analyzed the incidence of atrial arrhythmias in a population of 626 patients in 173 medical centers of eleven European countries and Japan with indication for a dual chamber pacemaker system. The accuracy of the new Automatic Interpretation for Diagnosis Assistance (AIDA) program which is included in Chorus pacemakers was evaluated and the AIDA analysis was compared to and proven with Holter monitoring. Data stored in the pacemakers' memories for the first 24 hours (D1) were compared with simultaneously recorded 24-hour surface electrocardiograms, and data stored over the following 28 days (D28) were examined against reported intercurrent symptoms.

RESULTS

At D1, atrial arrhythmias were detected by AIDA in 60 of 626 patients (12%), consisting of atrial fibrillation (n = 29), atrial flutter (n = 4), and miscellaneous arrhythmias (n = 17), and closely corroborated by Holter monitoring (sensitivity 93.7%, specificity 94.9%). At D28, 149 of 386 patients (49%) had had episodes of automatic mode switch prompted by atrial arrhythmias. Symptoms were reported by 81 patients (54%), 92 (62%) had no histories of atrial arrhythmias, and 57 patients (38%) were neither symptomatic nor had histories of atrial arrhythmias. An inverse relationship was found between the number of atrial paced events and the occurrence of atrial arrhythmias (p < 0.001). A history of atrial arrhythmias and older age were associated with a higher risk of atrial arrhythmias (p < 0.05). In contrast, gender, hypertension, concomitant heart disease, or type of atrial lead fixation system were not related with the occurrence of atrial arrhythmias.

CONCLUSION

AIDA allowed to confirm, or disprove, the occurrence of atrial arrhythmias as a source of symptoms reported during long-term follow-up. It could also be used to examine the efficacy of antiarrhythmic therapy, and be of assistance when weighing the needs for anticoagulation in patients experiencing asymptomatic atrial arrhythmias.

Size of emptied plaque cavity following spontaneous rupture is related to coronary dimensions, not to the degree of lumen narrowing. A study with intravascular ultrasound in vivo

OBJECTIVE

To identify any potential relations between the size of an emptied plaque cavity and the remodelling pattern, plaque or vessel dimensions, lumen narrowing, and other ultrasonic lesion characteristics.

DESIGN

Intravascular ultrasound was used to examine prospectively 51 ruptured ulcerated coronary plaques. Cross sectional area measurements comprised lumen, vessel, plaque, and emptied plaque cavity. Lumen narrowing was calculated as 1 - (lesion lumen area/reference lumen area) x 100%. A remodelling index was calculated as lesion vessel area/reference vessel area, and plaques were divided into those with values > 1.05 (group A) and </= 1.05 (group B).

RESULTS

Of the total of 51 plaques, 36 (71%) were assigned to group A and 15 (29%) to group B. In neither group was there a significant difference in reference dimensions and lumen narrowing. However, lesion vessel (mean (SD): 22.6 (8.1) mm(2) v 17. 5 (4.3) mm(2); p = 0.006) and plaque areas (15.8 (6.2) mm(2) v 12.8 (3.2) mm(2); p = 0.03) were greater in group A than in group B. The cavity inside the plaque was larger in group A than in group B (2.8 (1.6) mm(2) v 1.8 (0.9) mm(2); p = 0.007) and showed a positive linear relation with lesion and reference vessel size (r = 0.58 and 0.56, respectively; p < 0.001), but not with lumen narrowing.

CONCLUSIONS

The size of the emptied cavity inside ruptured plaques is on average larger in lesions with adaptive vascular remodelling, and shows a linear relation with lesion plaque and vessel size and with the reference dimensions, but not with the degree of lumen narrowing.

[Electromechanically controlled versus roengenologically guided percutaneous transluminal laser myocardial revascularization]

Transmyocardial laser revascularization is a modern therapeutic concept for patients with end-stage coronary artery disease not eligible for bypass surgery, percutaneous coronary interventions or heart transplantation. Although the principal idea of creating additional myocardial perfusion from the cavum of the left ventricle was derived from observations in reptile hearts, histological investigations suggest that channel patency is not the underlying mechanism for improved clinical symptoms. Sympathetic denervation and angioneogenesis may be additional explanations for improvement of angina and stress tolerance. The first experiences with transmyocardial laser revascularization were made using a surgical approach. Two randomized multicenter trials could show a significant improvement in angina and stress tolerance 12 months after creating channels using laser technique. While these results were obtained by performing thoracotomy, catheter-based systems have been designed for a less invasive approach of this technique. A further advantage of these new systems is that regions like the septum can be treated which are not eligible for a surgical approach. Using percutaneous transluminal catheter-based systems channels of up to 6 mm length can be created. Beside the fluoroscopic guided creation of myocardial channels a new mapping system has been applied using electromechanical features of viable myocardial tissue. This system is based on the observation that endocardial electrograms recorded from an infarcted area are characterized by very low amplitude and fractionated morphology. This system allows online mapping of viable myocardium and provides spatial, electrical, and mechanical information of the myocardium. This method of electromechanical mapping highly correlates with results obtained from myocardial perfusion scans. Recent preliminary clinical trials demonstrated that catheter-based creation of myocardial channels is a feasible and successful alternative to the surgical laser revascularization. Also with this approach a significant improvement in angina and stress tolerance can be achieved. The results of the PACIFIC study, the first randomized multicenter study using percutaneous transluminal laser revascularization, demonstrates that after 3 and 6 months more than half of the patients presented improved angina of at least 1 Canadian-Cardiovascular-Society class. Whether electromechanical guided myocardial laser revascularization is more efficient than fluoroscopic guided has not been proven yet. Further studies will have to evaluate this issue.

Corrected coronary flow velocity reserve: a new concept for assessing coronary perfusion

OBJECTIVES

In order to limit the variability of coronary flow velocity reserve (CFVR), we analyzed which factors independently affect CFVR and established a new parameter integrating these factors.

BACKGROUND

Coronary flow velocity reserve (CFVR) is a frequently used parameter for evaluating the physiological significance of epicardial stenosis and microvascular function. Since CFVR measurements are done in substantially different hemodynamic and clinical situations, interpretation of CFVR requires correction for major influencing factors.

METHODS

In 141 patients with angina-like symptoms and angiographically unobstructed coronary arteries, intracoronary Doppler measurements were performed in at least two coronary vessels. Coronary flow velocity reserve was calculated as the ratio of hyperemic average peak velocity (hAPV), after intracoronary bolus of adenosine, to baseline average peak velocity (bAPV).

RESULTS

Analysis of covariance revealed that only bAPV (p < 0.0001) and age (p < 0.0001) were independent factors influencing CFVR. Based on a regression model for estimation of predicted CFVR values, individual CFVR values (CFVRind) obtained at different bAPV and age were transformed in corrected CFVR values (CFVRcorr) by relating them to a mean bAPV of 15 cm/s and a mean age of 55 years. The transformation from CFVRind into CFVRcorr for the left anterior descending artery can be done by using the following equation: CFVRcorr = 2.85*CFVR(ind)*10(0.48*log(bAPV)+(0.0025*age)-1.16). When applying this new parameter to conditions assumed to cause microvascular dysfunction, analysis showed that only patients with diabetes showed a significant decrease of traditional CFVR and CFVRcorr, whereas a history of hypertension and current smoking habit had no influence on CFVRcorr.

CONCLUSIONS

The concept of CFVRcorr standardizes CFVR for bAPV and age as the major physiological determinants. Especially in patients with microvascular dysfunction, this approach may help to discriminate between conditions directly affecting vasodilator reserve and conditions primarily affecting bAPV.

Non-invasive characterization of cardiac microvascular disease by nuclear medicine using single-photon emission tomography

In about 10 to 30% of patients with typical angina undergoing coronary angiography for suspicion of stenotic coronary artery disease angiographically normal coronary arteries are found. Kemp et al. in 1973 coined the term syndrome X to describe this entity. In a substantial portion of these patients pathologic findings in myocardial scintigraphy are present. Sensitivity and specificity of thallium-201 exercise imaging by visual analysis of images in the presence of significant coronary stenosis is 84 and 88%, respectively. Several investigators have reported abnormal results in radionuclide exercise tests in patients with angiographically normal coronary arteries. Some of these results can be explained by myocardial bridging, vasospasm, left or right bundle branch block, hypertrophic cardiomyopathy, or absorption artifacts. In the majority of cases, however, these abnormalities are not sufficient to explain the scintigraphic findings. Formerly often claimed "false positive", recent studies suggest that endothelial dysfunction might be the reason for the observed perfusion defects. When comparing patients with angiographically unobstructed coronary arteries with and without perfusion defects in stress myocardial perfusion imaging, patients with pathological results show a significantly lower increase of coronary flow after intracoronary injection of the endothelial-dependent vasodilator acetylcholine. Endothelial-independent vasodilation, however, is not impaired in these patients. In addition, intracoronary Doppler measurements reveal that perfusion defects in myocardial scintigraphy only occur if coronary blood flow in this perfusion area is significantly reduced. These results suggest that regional endothelial dysfunction may cause hypoperfusion in myocardial perfusion imaging and underline the important role of the microcirculation in the distribution of radiotracers. Another striking scintigraphic pattern in patients with microvascular angina is the high incidence of reverse redistribution. These perfusion defects, apparent in images obtained 4 hours after exercise stress testing, often cannot be assigned to the perfusion territory of one of the major epicardial vessels. This results in a marked inhomogeneous radionuclide distribution pattern in resting images. The inhomogeneity is associated with a significant reduced resting coronary flow velocity in these patients. As histologically confirmed microvessel disease is often accompanied by slow-flow phenomenon reflecting decreased resting flow velocity, the results suggest that the inhomogeneous perfusion pattern is caused by microvascular dysfunction. Furthermore, the heterogeneity of nuclide distribution supports the hypothesis that endothelial function is not homogeneous in the entire myocardial microcirculation, but varies considerably. In conclusion, microvascular dysfunction by itself seems to cause regional myocardial hypoperfusion, as documented by myocardial scintigraphy. When interpreting pathological scintigraphic results in patients without significant epicardial stenosis, true blood flow and myocardial perfusion abnormalities must be assumed.

Early clinical experience with the implantation of a novel synthetic coronary stent graft

Coating stents with autologous venous grafts has been suggested to prevent problems associated with conventional stenting, but the need for surgical vessel harvest hampered broad application. A novel synthetic coronary stent graft (CSG) overcomes this limitation by a synthetic membrane, fixed between two thin metallic stents. We successfully implanted 21 CSGs in 18 patients for treatment of acute coronary rupture, thrombus-containing lesions, and lesions with plaque rupture or adjacent pseudoaneurysm. Substantial residual angiographic diameter stenoses were seen in seven CSGs (25% +/- 10% vs. 8% +/- 6%; P < 0.01), which were implanted with relatively small balloon catheters (balloon-to-artery ratio 1.00 +/- 0.09 vs. 1.24 +/- 0.18; P = 0.01) and required postdilatation. Overall, the largest balloon catheter applied measured 4.0 +/- 0.7 mm (balloon-to-artery ratio 1.21 +/- 0.20) and the inflation pressure was 16 +/- 3 atm. Final intravascular ultrasound imaging demonstrated adequate and symmetrical expansion of the CSG (> or = 85% +/- 15% of the reference lumen). Elective implantation was associated with two small non-Q-wave myocardial infarctions, resulting from unavoidable occlusions of side branches. Thus, implantation of CSG is feasible and safe. Adequate expansion can be achieved by the use of relatively large low-compliant balloon catheters inflated with high pressure.

[Treatment of coronary pseudoaneurysm by stent-graft implantation]

HISTORY AND CLINICAL FINDINGS

A 54-year-old man was urgently admitted because of sudden onset of progressively worsening angina pectoris, his first attack. Physical examination was unremarkable.

INVESTIGATIONS

Electrocardiography and laboratory tests excluded acute myocardial infarction. With the exception of hypercholesterolemia (total cholesterol 247 mg/dl) laboratory tests were normal. Coronary angiography revealed a 60% eccentric narrowing in the proximal part of the interventricular branch with adjacent aneurysmatic dilatation. Intravascular ultrasound (IVUS) showed a coronary pseudoaneurysm, its cavity communicating with the empty atheroma hole of an adjacent ruptured coronary plaque.

TREATMENT AND COURSE

A 19 mm stent graft was implanted, via a percutaneously inserted balloon-catheter system, in the region of the stenosis and the pseudoaneurysm. Subsequent angiography demonstrated a smooth nonstenotic lumen. The membrane of the graft (made of polytetrafluoroethylene [PTFE]), fixed between two thin metal stents, had occluded the pseudoaneurysm. Occlusion of an immediately distal septal branch briefly produced an asymptomatic rise of creatine kinase to maximally 173 U/l. Oral medication included ticlopidine hydrochloride (2 x 250 mg daily for 4 weeks). The patient was symptom-free after the procedure and was discharged 5 days later.

CONCLUSION

Implantation of a new type of stent-graft provides quick and uncomplicated treatment of a coronary aneurysm. The membrane fixed between two stents prevents wash out of any thrombi. The method may also be applicable to other potentially thrombus-containing lesions.

Predictive value of IgG subclass levels for infectious complications in renal transplant recipients

Renal allograft recipients are at risk to acquire infectious disease complications primarily after an intensified immunosuppressive therapy. In this study, serum levels of IgG, IgA, IgM and IgG subclasses were compared between transplant patients after different anti-rejection regimen and evaluated as possible predictive markers for infectious implications. Thirty-six renal transplant recipients in the early posttransplantation period were allocated into three subgroups: group 1 consisted of 15 subjects with good primary graft function standing under a basal triple drug immunosuppression; patients of group 2 (n = 9) had a very early acute rejection episode which was treated by high steroid doses and patients of group 3 (n = 12) required antithymocyte globulin (ATG) therapy for acute rejection. Immune parameters were studied 5 weeks after transplantation, when basal triple drug immunosuppression was continued in all patients. Twenty-three age-matched patients under chronic hemodialysis were recruited as a control group. Total IgG serum levels were reduced in transplant patients compared to dialysis subjects, whereas IgA and IgM levels were not altered. IgG subclass analysis revealed, that IgG1 levels were similar in stable transplant compared to chronic hemodialysis patients, but were significantly reduced in rejection patients after steroid pulses or ATG therapy. IgG3 levels were significantly reduced in all transplant recipients compared to dialysis patients without differences between the transplant subgroups. IgG2 and IgG4 subclass levels were similar in all studied subjects. IgG subclass abnormalities were paralleled by a reduction of lymphocyte subsets in rejection patients of groups 2 and 3, which may be the basis for an altered Ig class switching. Seven out of 36 studied transplant patients had severe infections in the early posttransplantation period with four cases of viral infections. Patients with infections had significantly lower IgG1 levels and CD4 positive lymphocyte numbers but similar total IgG levels compared to patients without infections. So IgG1 levels may be of value to predict the occurrence of infectious complications in renal allograft recipients in the early posttransplantation period.