Unmappable ventricular tachycardia after an old myocardial infarction. Long-term results of substrate modification in patients with an implantable cardioverter defibrillator.

PURPOSE: The frequent occurrence of ventricular tachycardia can create a serious problem in patients with an implantable cardioverter defibrillator. We assessed the long-term efficacy of catheter-based substrate modification using the voltage mapping technique of infarct-related ventricular tachycardia and recurrent device therapy. METHODS: The study population consisted of 27 consecutive patients (age 68 ± 8 years, 25 men, mean left ventricular ejection fraction 31 ± 9%) with an old myocardial infarction and multiple and/or hemodynamically not tolerated ventricular tachycardia necessitating repeated device therapy. A total of 31 substrate modification procedures were performed using the three-dimensional electroanatomical mapping system. Patients were followed up for a median of 23.5 (interquartile range 6.5-53.2) months before and 37.8 (interquartile range 11.7-71.8) months after ablation. Antiarrhythmic drugs were not changed after the procedure, and were stopped 6 to 9 months after the procedure in patients who did not show ventricular tachycardia recurrence. RESULTS: Median ventricular tachycardias were 1.6 (interquartile range 0.7-6.7) per month before and 0.2 (interquartile range 0.00-1.3) per month after ablation (P = 0.006). Nine ventricular fibrillation episodes were registered in seven patients before and two after ablation (P = 0.025). Median antitachycardia pacing decreased from 1.6 (interquartile range 0.01-5.5) per month before to 0.18 (interquartile range 0.00-1.6) per month after ablation (P = 0.069). Median number of shocks decreased from 0.19 (interquartile range 0.04-0.81) per month before to 0.00 (interquartile range 0.00-0.09) per month after ablation (P = 0.001). One patient had a transient ischemic attack during the procedure, and another developed pericarditis. Nine patients died during follow-up, eight patients due to heart failure and one patient during valve surgery. CONCLUSION: Catheter-based substrate modification using voltage mapping results in a long-lasting reduction of cardioverter defibrillator therapy in patients with multiple and/or hemodynamically not tolerated infarct-related ventricular tachyarrhythmia.

Implantation of cardiac resynchronization therapy systems in the CARE-HF trial: procedural success rate and safety.

AIMS: To assess procedural characteristics and adjudicated procedure-related (300 cm(3); and, influence of the participating study-centres. Implantation was attempted in 404/409 patients assigned to CRT, and in 65/404 patients assigned to medical therapy. Among these 469 patients, 450 (95.9%) received a successfully implanted and activated device. Complications occurred within 24 h in 47 patients (10.0%), mainly lead dislodgments (n = 10, 2.1%) and coronary sinus dissection/perforation (n = 10, 2.1%), and between 24 h and 30 days in 26 patients (5.5%), mainly lead dislodgment (n = 13, 2.8%). Mean LV lead stimulation threshold was significantly higher than at the right atrium or right ventricle, though remained stable, delivering effective, and reliable CRT. Implanting experience was the only predictor of procedural outcome. CONCLUSION: Transvenous CRT system implantation, using a CS lead designed for long-term LV pacing, was safe and reliable. As implanting centres become more experienced, this success rate is expected to increase further.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: new avenues for diagnosis and treatment.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disorder of unknown course that is characterised pathologically by fatty or fibrofatty replacement of the right ventricular myocardium and electrical instability. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation of ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD/C and they are distributed in the so-called 'triangle of dysplasia', i.e. the right ventricular outflow tract, apex and infundibulum. Ventricular aneurysms at these sites can be considered highly suggestive for ARVD/C. Another typical hallmark of ARVD/C is fatty or fibrofatty infiltration of the right ventricular free wall with potential extension to the left ventricle. These functional and morphological characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast-computed tomography and magnetic resonance (MR) imaging. Among these techniques, MR imaging allows the most comprehensive assessment of the heart, in particular because it provides functional and flow-dynamic information in addition to anatomic images. Furthermore, MR imaging offers the specific advantage of visualising adipose infiltration as a bright signal of the right ventricular myocardium. Non-pharmacological treatment by radio-frequency ablation and implantable defibrillators will play an increasing role in the treatment of patients with ARVD/C, especially in case of drug ineffectivity. Despite new diagnostic and therapeutic approaches in ARVD/C, there remain many unanswered issues since the current guidelines present criteria that are highly specific but lack sensitivity. Therefore, optimal assessment of diagnostic criteria would require a prospective evaluation from a large population obtained by an international registry.

17beta-estradiol attenuates the development of pressure-overload hypertrophy.

BACKGROUND: Cardiac hypertrophy is an independent risk factor for cardiovascular morbidity and mortality in men and in women. Epidemiological studies indicate that estrogen replacement therapy is cardioprotective; the mechanisms involved in this process, however, are poorly understood. We therefore studied the effect of 17beta-estradiol (E(2)) on the development of pressure-overload hypertrophy. METHODS AND RESULTS: Ovariectomized mice receiving E(2) or placebo underwent transverse aortic constriction (TAC) or sham operation. TAC led to a significant increase in ventricular mass compared with sham operation. E(2) treatment reduced cardiac hypertrophy by 31% and 26% compared with placebo 4 and 8 weeks after TAC, whereas it had no effect on the degree of pressure overload, as determined by hemodynamic measurements. Furthermore, E(2) blocked the increased phosphorylation of p38-mitogen-activated protein kinase (MAPK) observed in the placebo-treated animals with TAC. No differences were observed in the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) 1/2 between the groups. E(2) had no effect on the expression of angiotensin-converting enzyme (ACE) or the angiotensin II type 1 receptor. Ventricular atrial natriuretic peptide (ANP) expression was detected only in the animals with TAC. Compared with placebo, E(2) treatment led to an increased expression of ANP in animals with pressure overload. CONCLUSIONS: Here, we show that E(2) attenuates the hypertrophic response to pressure overload in mice. This observation demonstrates that hormone replacement therapy with E(2) has direct effects on the heart and may be beneficial in the treatment of postmenopausal women to reduce cardiac hypertrophy.

Radiofrequency modified maze in patients with atrial fibrillation undergoing concomitant cardiac surgery.

OBJECTIVE: In the majority of patients with chronic atrial fibrillation the arrhythmia will persist after correction of the underlying structural abnormality. The maze procedure is an effective surgical method to eliminate atrial fibrillation and to restore atrial contractility. METHODS: In this study we used radiofrequency energy to create lines of conduction block in both atria during cardiac surgery as a modification of the maze III procedure. One hundred twenty-two patients with atrial fibrillation for at least 1 year and structural heart disease underwent open heart operation and a radiofrequency modified maze procedure. RESULTS: In 108 (89%) of 122 patients mitral valve surgery was performed, and in this group 86 patients (80%) underwent 121 concomitant procedures. Fourteen patients (11%) underwent cardiac surgery not involving the mitral valve. The additional crossclamp time required for the left atrial part of the radiofrequency modified maze procedure was 14 +/- 3 minutes. The in-hospital mortality rate was 4.1%. The overall 39-month survival was 90%, and freedom of atrial flutter or atrial fibrillation was 78.5% +/- 5.1%. Eighty-nine survivors with sinus, atrial rhythm, or atrioventricular sequential pacemaker had Doppler echocardiography, and right atrial transport function was documented in 83% and left atrial transport function in 77% of patients. CONCLUSION: We concluded that the radiofrequency modified maze procedure as an adjunctive procedure is safe, time-sparing, and effective in eliminating atrial fibrillation and restoring atrial transport function.

The radiofrequency modified maze procedure. A less invasive surgical approach to atrial fibrillation during open-heart surgery.

OBJECTIVE: Patients with mitral valve disease and suffering of atrial fibrillation of more than 1 year's duration have a low probability of remaining in sinus rhythm after valve surgery alone. Intraoperative radiofrequency ablation was used as an alternative to simplify the surgical maze procedure. METHODS: Seventy-two patients with mitral valve disease, aged 63+/-11 years ranging from 31 to 80 years, underwent valve surgery and radiofrequency energy applied endocardially, based on the maze III procedure to eliminate the arrhythmia. The right-sided maze was performed on the beating heart and the left-sided maze during aorta cross-clamping. RESULTS: Surgical procedures included mitral valve repair (n=38) or replacement (n=34) and in addition tricuspid valve repair (n=42), closure of an atrial septal defect (n=2) and correction of cor triatriatum (n=1). The left-sided maze needed 14+/-3 min extra ischemic time. There were two in-hospital deaths (2.7%) and three patients (4.2%) died during follow-up of 20+/-15 months. Among 67 surviving patients, 51 patients (76%) were in sinus rhythm, two patients (3%) had an atrial rhythm and eight patients (12%) had persistent atrial fibrillation or atrial flutter. Four patients had a pacemaker implanted, in one patient because of sinus node dysfunction. Doppler echocardiography in 64 patients demonstrated right atrial contractility in 89% and left atrial transport in 91% of patients. CONCLUSIONS: Intraoperative radiofrequency ablation of atrial fibrillation is an effective and less invasive alternative for the original maze procedure to eliminate atrial fibrillation.

Acute and short-term effects of partial left ventriculectomy in dilated cardiomyopathy: assessment by pressure-volume loops.

OBJECTIVES: The aim of this study was to evaluate the short-term effects of partial left ventriculectomy (PLV) on left ventricular (LV) pressure-volume (P-V) loops, wall stress, and the synchrony of LV segmental volume motions in patients with dilated cardiomyopathy. BACKGROUND: Surgical LV volume reduction is under investigation as an alternative for, or bridge to, heart transplantation for patients with end-stage dilated cardiomyopathy. METHODS: We measured P-V loops in eight patients with dilated cardiomyopathy before, during and two to five days after PLV. The conductance catheter technique was used to measure LV volume instantaneously. RESULTS: The PLV reduced end-diastolic volume (EDV) acutely from 141+/-27 to 68+/-16 ml/m2 (p < 0.001) and to 65+/-6 ml/m2 (p < 0.001) at two to five days postoperation (post-op). Cardiac index (CI) increased from 1.5+/-0.5 to 2.6+/-0.6 l/min/m2 (p < 0.002) and was 1.8+/-0.3 l/min/m2 (NS) at two to five days post-op. The LV ejection fraction (EF) increased from 15+/-8% to 35+/-6% (p < 0.001) and to 26+/-3% (p < 0.003) at two to five days post-op. Tau decreased from 54+/-8 to 38+/-6 ms (p < 0.05) and was 38+/-5 ms (NS) at two to five days post-op. Peak wall stress decreased from 254+/-85 to 157+/-49 mm Hg (p < 0.001) and to 184+/-40 mm Hg (p < 0.003) two to five days post-op. The synchrony of LV segmental volume changes increased from 68+/-6% before PLV to 80+/-7% after surgery (p < 0.01) and was 73+/-4% (NS) at two to five days post-op. The LV synchrony index and CI showed a significant (p < 0.0001) correlation. CONCLUSIONS: The acute decrease in LV volume in heart-failure patients following PLV resulted at short-term in unchanged SV, increases in LVEF, and decreases in peak wall stress. The increase in LV synchrony with PLV suggests that the transition to a more uniform LV contraction and relaxation pattern might be a rationale of the working mechanism of PLV.

The incidence and consequences of mental disturbances in elderly patients post cardiac surgery--a comparison with younger patients.

BACKGROUND: Limited data exist about the incidence and consequences of mental confusion following open heart surgery in different age groups. Likewise, little is known about preoperative predictors of mental confusion. METHODS: Two-hundred consecutive patients, aged > or =75 years (Group 1), and 400 procedure- and gender-matched younger patients (Group 2) who underwent coronary or valvular surgery were included in a prospective study. The relation between postoperative mental confusion, mortality, morbidity, and quality of life was studied. RESULTS: Mental confusion was present in 11.8% Group 2 and 22.6% Group 1 patients. The incidence was higher after valvular surgery. Preoperative risk factors in Group 1 patients were diabetes mellitus, a history of heart failure, weak carotid pulsations, and repeat surgery. Late mortality, after a median follow-up duration of 31 months, was significantly worse in patients who were confused, which was related to the underlying disease. Recovery of quality of life was clearly diminished in elderly patients with confusion in contrast to younger patients. CONCLUSION: Postoperative mental confusion has a high incidence in the elderly population and is associated with a diminished quality of life.

Risk indicators for out-of-hospital cardiac arrest in patients with coronary artery disease.

The objective of this study was to identify risk factors for sudden cardiac arrest (SCA) in patients with coronary artery disease (CAD). A retrospective case-control study was performed consisting of a group of unselected patients who had suffered SCA and had a clinical history of CAD, and a group of unselected age- and gender-matched CAD control patients living in the region of Maastricht. Information about previous myocardial infarction (MI), left ventricular ejection fraction (LVEF), hypertension, hypercholesterolemia, diabetes mellitus, smoking, and coffee and alcohol consumption was collected. A logistic regression model was fitted to all mentioned variables including age and genders. Included were 117 SCA cases (84% men, mean age 65 years [+/-7]) and 144 control patients (83% men, mean age 63 years [+/-8]). Previous MI (odds ratio [OR] 4.0, 95% confidence interval [CI] 1.7-9.3), hypertension (OR 2.9, 95% CI 1.5-6.1), heavy coffee consumption (>10 cups per day) (OR 55.7, 95% CI 6.4-483), and a LVEF <40% (OR 11.2, CI 4.4-28.5) were independent risk indicators for SCA in patients with CAD. Alcohol consumption (1-21 glasses per week) seemed to protect patients with CAD from SCA (OR 0.5, 95% CI 0.2-0.98). These observations suggest that changes in lifestyle factors can be of potential importance in protecting patients with CAD from dying suddenly.

Biphasic pattern of cell turnover characterizes the progression from fatty streaks to ruptured human atherosclerotic plaques.

OBJECTIVE: To study the amount and phenotype of DNA-synthesizing and apoptotic cells during atherogenesis. METHODS: Atherosclerotic lesions (n = 76), obtained at autopsy (N = 6) or during vascular surgery (N = 8), were classified [type I-VI; American Heart Association (AHA) classification], immunolabeled with MIB 1 or the TUNEL technique and double stained with cell-type-specific antibodies. Subsequently, the labeled fractions were quantified. RESULTS: In type II-VI lesions, intimal DNA synthesis was increased compared to that of the non-diseased (ND) arterial wall. DNA synthesis peaked in early type II lesions (2.7 +/- 0.5 vs. 0.02 +/- 0.02% in ND; p < 0.05), and declined to 0.7 +/- 0.2% in type V lesions (p < 0.05). Interestingly, a second peak of DNA synthesis of 1.7 +/- 0.1%, was observed in type VI (ruptured plaque) lesions. Double staining revealed that DNA synthesis was mostly confined to the macrophage-derived foam cell (51.9%). In type II lesions, 100.0% of all DNA-synthesizing cells were present in the intimal foam cell-rich area, while in advanced type III, IV and V lesions, DNA synthesis had shifted to the shoulder region (74.8, 78.5 and 68.1%, respectively). In type VI lesions, DNA synthesis was present in the area underlying the plaque rupture (52.7%). Apoptosis was only elevated in advanced type IV, V and VI lesions (0.8 +/- 0.1, 0.8 +/- 0.1 and 1.1 +/- 0.1%, respectively, vs. 0.0 +/- 0.0% in ND) and was predominant in the lipid core (90.5% in type IV lesions; 54.2% in type V lesions) or equally divided between the lipid core and the region underlying the plaque rupture (31.8 and 34.6% in type VI lesions). In type III-VI lesions, 50.0, 38.9, 42.6 and 42.8% of the TUNEL-positive cells were macrophages. CONCLUSIONS: In stable atherosclerotic lesions, DNA synthesis is an early event, while apoptosis is a late event. Ruptured plaques show a second peak of cell turnover. Lastly, cell turnover is mostly confined to the macrophage-derived foam cell.

Comparison of quality of life after coronary and/or valvular cardiac surgery in patients > or =75 years of age with younger patients.

Quality of life after cardiac surgery appeared to be comparable in patients aged > or =75 years and younger patients. Preoperative depression had more impact on postoperative well-being in the elderly compared with younger patients.

Radiofrequency ablation of "class IC atrial flutter" in patients with resistant atrial fibrillation.

In some patients with atrial fibrillation, atrial flutter develops after administration of class IC antiarrhythmic drugs, the so-called class IC atrial flutter. Radiofrequency ablation of the right atrial isthmus results in clinical improvement in 85% of patients and provides an alternative management strategy for a subset of patients with therapy-resistant atrial fibrillation.

Transvenous cold mapping and cryoablation of the AV node in dogs: observations of chronic lesions and comparison to those obtained using radiofrequency ablation.

INTRODUCTION: Radiofrequency (RF) is the most commonly used energy source for the treatment of cardiac arrhythmias. Surgical experience has shown that cryoablation also is effective for ablating arrhythmias. The aims of this study were to (1) investigate the feasibility of inducing permanent complete AV block (CAVB), (2) investigate the value of cold mapping to select the cryoablation site to produce permanent CAVB, (3) study the macro- and microscopic lesion characteristics 6 weeks later, and (4) compare them to those produced with RF energy. METHODS AND RESULTS: A new steerable 8.5-French bipolar electrode catheter having a thermocouple with a 3-mm tip using N2O as the refrigerant controlled by a cryoconsole was used. Six mongrel dogs were anesthetized, and the catheter was positioned via the femoral vein across the tricuspid valve to record a large low right atrial and a small His-bundle potential. After cold mapping (-15 degrees to -20 degrees C tip temperature) resulted in ECG modifications, cryothermia (-70 degrees C) was given twice, lasting 5 minutes each, to create permanent CAVB (Cryo group). Additionally, RF catheter ablation of the AV node was performed in two anesthetized mongrel dogs (RF group). In the Cryo group, a permanent proximal CAVB was created in four dogs (block occurred within 10 to 20 sec of cryothermia). Permanent right bundle branch block was obtained in one dog and transient CAVB in the remaining dog. In both dogs of the RF group, permanent CAVB was obtained. The cryolesions consisted of well-circumscribed, homogeneous areas of fibrotic tissue without viable cardiomyocytes. Lesions produced with RF were less circumscribed and inhomogeneous, with clear evidence of viable cardiomyocytes and cartilage formation (patchy lesions). CONCLUSIONS: (1) Permanent CAVB can be created by using a steerable cryoablation catheter. (2) Histologically, cryoablated sites were homogeneous and showed fibrotic tissue without signs of chronic inflammation and no evidence of viable myocytes. (3) Lesions created with RF were less homogenous and still contained viable myocytes within the lesion and cartilage formation. (4) The arrhythmogenic significance of these differences requires further study. (5) The technology of using reversible cold mapping has the potential to identify the successful ablation site and warrants further clinical study.

Preserved skeletal muscle structure with modified electrical stimulation protocol in a cardiomyoplasty patient: a clinico-pathological report.

Experimental and clinical studies have recently shown variable degrees of structural abnormalities in the transposed and chronically stimulated muscle graft after cardiomyoplasty procedure. The postoperative stimulation protocol of wrapped skeletal muscle has been claimed to be a major determinant of late structural derangement. Therefore, a modified stimulation protocol had been used after a cardiomyoplasty procedure in a 63-year-old patient. Improved postoperative hemodynamic data could be detected by pressure/volume analysis. After unexpected sudden death occurred at 15 months, autoptic examination showed preserved muscle structure, suggesting that a prudent stimulation protocol may maintain muscle viability and contribute to effective cardiac support.

Structural alterations in the latissimus dorsi muscles in three patients more than 2 years after a cardiomyoplasty procedure.

AIMS: The long-term effects of the use of the latissimus dorsi muscle for dynamic cardiomyoplasty were studied. Skeletal muscle fast fatiguable type II fibres are transformed to highly fatigue-resistant type I fibres in animal models, and is assumed to occur in men. However, it is not known whether this same transformation occurs in patients with chronic heart failure. METHODS AND RESULTS: Three patients who underwent a cardiomyoplasty procedure (pre-operative NYHA class IV) were studied. The left latissimus dorsi muscle was stimulated, according to routine clinical protocol, with 30 Hz bursts in a 2:1 ratio to cardiac activation. The patients died more than 2 years after surgery and five autopsy samples were obtained at defined places in the wrapped muscle. In the proximal part of the latissimus dorsi muscle, the type I fibres comprised 68-80% in all three patients, whereas peroperatively type I fibres comprised 17-30% indicating significant but not complete transformation. Transformation in the latissimus dorsi muscle as a whole appeared to be inhomogeneous, with type I fibres ranging from 10-80%. An extensive amount of muscle fibre appeared to be replaced by fatty tissue (10%-50%). This occurred at random and resulted in complete loss of muscle structure. A significant increase in the density of small arteries was observed in the latissimus dorsi after transformation. CONCLUSIONS: In these patients, muscle fibre type transformation was not as complete as that observed in animal experiments, and was accompanied by loss of muscle viability. The stimulation current in the latissimus dorsi muscle appeared not to be the direct cause of local tissue lipomatosis or collagen deposition.

Internal balloon compression: a method to achieve hemostasis when removing an inadvertently placed pacemaker lead from the subclavian artery.

One of the possible complications of subclavian vein puncture is entry into the subclavian artery. If this is not recognized, a pacemaker lead may be placed arterially. Since this may lead to systemic emboli, the pacemaker lead must be removed. This case report describes a patient in whom an atrial lead was inadvertently placed in the ascending aorta, where it had good sensing values but poor atrial capture threshold values. This lead was subsequently removed and hemostasis was achieved with intraarterial balloon compression via the brachial artery.

Changing characteristics and in-hospital outcome in patients admitted with acute myocardial infarction. Observations from 1982 to 1994.

BACKGROUND: During the past decade, various new treatments have become available for patients with acute myocardial infarction. The effects of these treatment modalities have been studied extensively in selected patient groups. These studies indicate that early diagnosis, risk stratification and prompt initiation of treatment are of crucial importance for optimal benefit. However, it is not known whether prognosis changed in all patients admitted with an acute myocardial infarction. Also, the characteristics of the infarct population may have changed over time because of new medication regimens, invasive interventions and awareness of the importance of risk factors. METHODS: We studied all patients admitted with acute myocardial infarction in 1982, 1988 and 1994. Information on baseline characteristics, clinical variables and all interventions was collected. FINDINGS: In those 3 years 223, 227 and 235 patients were admitted because of an acute myocardial infarction. Patients admitted in 1994 were older, more often female and less often had a previous cardiac history. More patients admitted in that year had previous balloon angioplasty and coronary bypass grafting. Smoking habits decreased during the past decade. In-hospital mortality was 38 (17%) in 1982, 23 (10%) in 1988 and 22 (9%) in 1994 (P < 0.05). Variables related to high risk for in-hospital death in 1982 were higher age, low systolic blood pressure, atrial fibrillation, absence of accelerated idioventricular rhythm, sustained ventricular tachycardia and signs of left ventricular dysfunction; in 1988 the occurrence of non-sustained ventricular tachycardia, Killip class more than I, the absence of thrombolytic therapy, percutaneous transluminal coronary angioplasty or coronary artery bypass grafting were independently related to in-hospital death. In 1994, high risk variables for in-hospital death were dyspnoea on admission, sustained ventricular tachycardia, female gender, higher creatinine on admission, and a previous cardiac history. INTERPRETATION: In-hospital mortality for unselected patients admitted with an acute myocardial infarction decreased between 1982 and 1988 and remained the same between 1988 and 1994, in spite of further ageing of the population. In the study period there has been a change in baseline characteristics and high risk variables for in-hospital death after myocardial infarction.

Removal of thrombus from aortocoronary bypass grafts and coronary arteries using the 6Fr Hydrolyser.

This study evaluates the feasibility and safety of a 6Fr hydrodynamic thrombectomy catheter, the Hydrolyser, in native coronary arteries and aortocoronary bypass grafts. With use of a conventional contrast injector, saline solution is injected into the narrow lumen of the catheter which makes a 180 degrees bend at the tip. The resultant high-velocity jet (150 km/hour) is directed over a sidehole near the tip into a wide exhaust lumen. As a consequence of the Venturi effect, thrombus is sucked into that sidehole, fragmented, and removed through the wide exhaust lumen into a collection bag. Thirty-one thrombotic lesions were treated in 31 patients. The culprit vessel was a venous graft in 21 patients (15 with Thrombolysis in Myocardial Infarction Trial [TIMI] grade 0 or 1 flow) and a coronary artery in 11 patients (9 with grade 0 or 1 flow). Twenty-six patients had angina New York Heart Association functional class III or IV heart failure and 5 an acute myocardial infarction. In 26 patients, Hydrolyser therapy was the primary treatment, whereas in 5 patients coronary angioplasty preceded Hydrolyser therapy. In 1 patient the Hydrolyser could not reach the lesion. Thrombus was removed in 29 of the 31 patients. Successful reperfusion (TIMI grade 2 or 3 flow) by Hydrolyser therapy alone was achieved in 14 of the 24 patients with TIMI grade 0 or 1 flow before the procedure. Adjunctive therapy (coronary angioplasty, stent, or thrombolysis) was performed in 28 of the 31 patients. At the end of the total procedure 24 patients had TIMI grade 3 flow. Distal embolization during thrombectomy occurred in 2 patients, which led to a non-Q-wave infarction in 1. No patient died or needed emergency coronary bypass due to the Hydrolyser procedure. Thus, thrombectomy using the 6Fr Hydrolyser is feasible and was performed safely in 31 patients.

Configuration of unipolar atrial electrograms during electrically induced atrial fibrillation in humans.

BACKGROUND: During atrial fibrillation (AF), the atrium is activated by multiple wavelets that continuously change in size and direction. The aim of this study was to correlate the temporal variation in AF electrogram configuration with the varying spatial patterns of activation. METHODS AND RESULTS: In a group of 25 Wolff-Parkinson-White patients undergoing cardiac surgery, the free wall of the right atrium was mapped (244 points) during electrically induced AF. The unipolar electrograms recorded during 4 seconds of AF were classified into four categories: (1) single deflections, (2) short-double potentials, (3) long-double potentials, and (4) fragmented potentials. The proportion of these four types of electrograms during AF was as follows: singles, 77 +/- 12%; short-doubles, 7 +/- 3%; long-doubles, 10 +/- 7%; and fragmented, 6 +/- 4%. Electrogram morphology was an indicator for rapid uniform conduction (single potentials; positive predictive value [PPV] of 0.96), collision (short-double potentials; PPV of 0.33), conduction block (long-double potentials; PPV of 0.84), and pivoting points or slow conduction (fragmented potentials; PPV of 0.87). In type I, II, and III AF, the proportion of long-double potentials was 4 +/- 2%, 12 +/- 3%, and 18 +/- 7% (P < .05); the proportion of fragmented complexes was 2 +/- 2%, 6 +/- 3%, and 10 +/- 4% (P < .05), respectively. During electrically induced and self-terminating episodes of AF, no preferential anatomic sites for double or fragmented potentials were found in the right atrium. CONCLUSIONS: The morphology of single unipolar electrograms during AF reflects the occurrence of various specific patterns of conduction. This might be used to differentiate between different types of AF and to identify regions with structural conduction disturbances involved in perpetuation of chronic AF.