Biomedical subjects

Oussama Wazni

Publications and source records attributed to Oussama Wazni.

14 recordsLinked to original sources

PubMed2006

Improved survival after acute myocardial infarction complicated by cardiogenic shock with circulatory support and transplantation: comparing aggressive intervention with conservative treatment.

BACKGROUND: The prognosis for patients with myocardial infarction has steadily improved, but remains poor for those developing cardiogenic shock. Utilization of re-vascularization, mechanical circulatory support and transplantation in these patients may improve survival. METHODS: We retrospectively analyzed the clinical outcome of 138 consecutive patients at the Cleveland Clinic from 1992 to 1998 who met the criteria for cardiogenic shock after acute myocardial infarction. All patients received intensive medical therapy and intra-aortic balloon pump support. Forty-three patients received intensive medical therapy (conservative group) and 95 patients were treated aggressively (aggressive group). The aggressive group comprised patients who were treated with percutaneous intervention/coronary artery bypass grafting (n = 77, re-vascularization group), and patients who received circulatory support/cardiac transplantation (n = 18). RESULTS: The baseline demographics and angiographic and hemodynamic features were comparable for the two groups. The in-hospital mortality rate was significantly reduced in the aggressive group compared with the conservative group (54% vs 81%, p = 0.002). The in-hospital mortality rate of the circulatory support/transplant group was markedly reduced compared with the conservative group (33% vs 81%, p < 0.001), and was also significantly lower than that of the re-vascularization group (33% vs 63%, p= 0.03). The aggressive group had a markedly improved 5-year survival compared with the conservative group (30% vs 6.2%, p = 0.003). CONCLUSIONS: These data suggest that an aggressive strategy, particularly left ventricular assist device support as a bridge to heart transplantation, may improve survival in post-myocardial infarction patients with cardiogenic shock.

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PubMed2006

Efficacy of catheter ablation of atrial fibrillation in patients with hypertrophic obstructive cardiomyopathy.

BACKGROUND: Although pulmonary vein (PV) antrum isolation is effective in curing atrial fibrillation (AF) in a variety of heart diseases, results in patients with hypertrophic obstructive cardiomyopathy (HOCM) have not been reported. OBJECTIVES: The purpose of this study was to report the results and outcome of PV antrum isolation in patients with AF and HOCM. METHODS: Data from patients with AF and HOCM who underwent PV antrum isolation between February 2002 and May 2004 were analyzed retrospectively. An intracardiac echocardiographic-guided ablation technique with an 8-mm-tip catheter was used in all patients. Patients were followed in the outpatient clinic at 3, 6, and 12 months after ablation. RESULTS: Twenty-seven patients with AF and HOCM (mean age 55 +/- 10 years) underwent PV antrum isolation. Mean AF duration was 5.4 +/- 3.6 years. AF was paroxysmal in 14 (52%), persistent in 9 (33%), and permanent in 4 (15%). During a mean follow-up of 341 +/- 237 days, 13 patients (48%) had AF recurrence. Of these patients, five maintained sinus rhythm (SR) with antiarrhythmic drugs, one patient remained in persistent AF, and seven patients underwent a second PV antrum isolation. After the second PV antrum isolation, five patients remained in SR, giving a final success rate of 70% (19/27). Two patients had recurrence after second PV antrum isolation; one maintained SR with antiarrhythmic drugs and one remained in persistent AF. CONCLUSION: Compared with previously reported results in patients with lone AF, AF recurrence after the first PV antrum isolation is higher in patients with HOCM. However, after repeated ablation procedures, long-term cure can be achieved in a sizable number of patients. PV antrum isolation is a feasible therapeutic option in patients with AF and HOCM.

Atrial Fibrillation↗

PubMed2006

Avoiding microbubbles formation during radiofrequency left atrial ablation versus continuous microbubbles formation and standard radiofrequency ablation protocols: comparison of energy profiles and chronic lesion characteristics.

BACKGROUND: Radiofrequency (RF) energy parameters and chronic lesion characteristics associated with the microbubbles formation have not been yet fully elucidated. OBJECTIVES: The objective of this study was to compare the energy profiles and chronic lesion characteristics associated with RF ablation of the pulmonary vein antrum using three different ablation protocols: (1) avoiding microbubbles; (2) continuous microbubble formation; (3) temperature-guided ablation. METHODS: A 4-mm tip ablation catheter was used for creating RF ablation lesions in 15 adult mongrel dogs. All ablation lesions were created at the posterior aspect of the PV antrum in each animal. Avoiding microbubbles (group 1, n = 5 dogs, 23 lesions), continuous microbubble formation (group 2, n = 5 dogs, 22 lesions), and temperature-guided (group 3, n = 5 dogs, 19 lesions, target temperature 60 degrees C/power limit 50 W) ablation lesions were analyzed. RESULTS: Group 1 showed significantly lower power (19 +/- 8.6 W), lower temperature (50 +/- 4.8 degrees C), higher efficiency-of-heating index (2.9 +/- 0.8 degrees C/W), and lower impedance (109 +/- 24.4 Omega) than groups 2 (38 +/- 8.4 W; 63 +/- 10 degrees C; 1.8 +/- 0.8 degrees C/W; 148 +/- 34.4 Omega) and 3 (44 +/- 12 W; 57 +/- 2.4 degrees C; 1.4 +/- 0.5 degrees C/W; 139 +/- 23.1 Omega) (P < 0.001 vs groups 2 and 3). During ablation, no significant events were detected in group 1, but 11 cases of audible pop, 11 cases of catheter tip charring, and 1 case of fatal myocardial perforation were observed in groups 2 and 3. Transmural lesions were more frequently created in group 1. CONCLUSION: RF energy delivery applying "avoiding microbubbles" protocol seems to be associated with higher degree of safety and efficacy when compared to temperature-guided and continuous microbubble-formation ablation protocols.

Animals↗

PubMed2006

Transcranial Doppler detection of microembolic signals during pulmonary vein antrum isolation: implications for titration of radiofrequency energy.

BACKGROUND: Cerebrovascular events are an important complication during pulmonary vein antrum isolation (PVAI). Microembolic signals (MES) have been associated with stroke and neurological impairment. However, the incidence of MES during PVAI, and their relationship to microbubble formation and radiofrequency (RF) parameters are unknown. OBJECTIVES: We sought to assess the relationship between MES, microbubble detection, and neurological outcome and the impact of RF titration strategy on these parameters. METHODS: We studied 202 patients in two groups undergoing PVAI using an intracardiac echocardiography (ICE)-guided technique. MES were detected by transcranial Doppler (TCD) using insonation of the middle cerebral arteries. The number of microbubbles on ICE were qualitatively labeled as FEW, MODERATE, and SHOWER. In group I (n = 107), RF output was titrated to avoid microbubble formation and in group II (n = 95), standard power-limited RF output was used. RESULTS: TCD detected MES in all 202 patients during PVAI with an average of 1,793 +/- 547 per patient; 90% were detected during left atrial ablation. Over 85% of MES occurred after microbubbles. Group I patients had significantly lower numbers of MES (1,015 +/- 438 per patient) compared to group II patients (2,250 +/- 864 per patient) (P < 0.05). Group II also had a 3.1% incidence of acute neurological complications versus 0.9% in group I (P = 0.10). Patients with clinical events had significantly higher numbers of MES. There were no significant correlations between RF power, temperature, or impedence and MES number. CONCLUSIONS: MES directly correlate to the amount of microbubble formation on ICE, and may result in cerebroembolic complications. Titration of RF according to microbubble formation by ICE during PVAI may be important for minimizing the occurrence of MES and possibly acute neurological complications.

Atrial Fibrillation↗

PubMed2006

Incidence of atrial fibrillation in heart transplant patients: long-term follow-up.

BACKGROUND: The incidence of atrial fibrillation (AF) in heart transplant patients has not been well documented. METHODS: To determine the incidence of AF in a cohort of patients undergoing cardiac transplantation, clinical data were obtained from a prospectively collected database for all consecutive orthotopic heart transplantation (OHT) patients and for all consecutive coronary artery bypass graft (CABG) surgery patients between January 1984 and March 2004 at our institution. A cohort of 1,714 OHT patients and low-risk CABG (normal ejection fraction [EF] and no left ventricular hypertrophy [LVH]) patients were age- and sex-matched. RESULTS: The average age in the two groups was 56 +/- 7 years with 87% male and 81% white race and body mass index (BMI) of 26 +/- 4. There were 3 cases of AF (0.3%) in the OHT group and 757 cases of AF (21%) in the low-risk CABG group. The strongest independent predictor of freedom from postoperative AF was having had a transplant (odds ratio [OR] 96, 95% confidence interval [CI] 13-720). The incidence of AF, atrial flutter (AFL), and supraventricular tachycardia (SVT) in OHT was 0.33, 2.8%, and 1.3%, respectively. Given that incidence of AF, AFL, and SVT in historical post-CABG population is 25%, 17%, and 4.3%, transplanted patients appear to have lower incidence of AF, AFL, and SVT than the reference population. Consistent with this, transplanted patients underwent few ablation procedures for atrial arrhythmias. Additionally, the three patients with AF had bicaval anastomoses suggesting the possibility of PACs originating in the donor superior vena cava (SVC) or IVC (inferior vena cava) initiating AF in these patients. CONCLUSIONS: In a cohort study of transplant and low-risk CABG patients, the strongest independent predictor of freedom from AF is having undergone transplant surgery. One potential explanation for the markedly lower incidence of AF may be effective isolation of thoracic veins with documented cases retaining the native SVC.

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PubMed2005

The need for atrial flutter ablation following pulmonary vein antrum isolation in patients with and without previous cardiac surgery.

OBJECTIVES: The aim of this study was to assess the incidence of atrial flutter (AFL) after pulmonary vein antrum isolation (PVAI) in patients with previous cardiac surgery (PCS) in comparison to patients without PCS and to assess the need for AFL ablation in both groups. BACKGROUND: Atrial fibrillation (AF) and AFL often co-exist. Pulmonary vein antrum isolation may be sufficient to control both arrhythmias. However, in patients with PCS, atrial incisions, cannulations, and scar areas may cause AFL recurrence despite elimination of pulmonary vein triggers. METHODS: Data from 1,345 patients who had PVAI were analyzed. Patients with a history of AFL ablation and patients who had concomitant AFL ablation during PVAI were excluded from analysis. Sixty-three patients constituted the PCS group (Group 1, age 57 +/- 13 years, 12 female) and 1,062 patients constituted the non-PCS group (Group 2, age 55 +/- 12 years, 212 female). Patients in Group 1 had larger left atria, higher incidence of AFL pre-PVAI, and lower ejection fraction. RESULTS: There was no significant difference in post-PVAI AF recurrence between Groups 1 and 2, but AFL incidence after PVAI was higher in Group 1 (33% vs. 4%, p < 0.0001). Ablation of AFL in Group 1 patients resulted in an 86% acute success rate and 11% recurrence over a mean follow-up of 357 +/- 201 days. CONCLUSIONS: In patients with PCS, post-PVAI AF recurrence is similar to patients without PCS. However, history of PCS is associated with a higher recurrence of AFL after PVAI. In a significant number of patients with PCS, AFL ablation is required to achieve a cure.

Adult↗

PubMed2005

Safety and efficacy of radiofrequency energy catheter ablation of atrial fibrillation in patients with pacemakers and implantable cardiac defibrillators.

BACKGROUND: Catheter ablation has significantly transformed the clinical management of atrial fibrillation (AF). The safety and efficacy of this procedure are not well understood in patients with pacemakers and defibrillators. OBJECTIVES: The purpose of this study was to study the impact of radiofrequency catheter ablation of AF in patients with pacemakers and implantable cardiac defibrillators. METHODS: We studied 86 patients with pacemakers and defibrillators (group I) and a similar number of age- and gender-matched controls (group II) who underwent AF ablation between 1999 and 2004. Clinical and procedural variables were compared between the two groups. In group I, various generator and lead parameters were compared before and after the procedure. Resurgence of clinical AF after 2 months was considered recurrence. RESULTS: Both groups were similar with regard to age, gender, body mass index, and type of AF. Group I had a higher incidence of diabetes (17% vs 6%, P = .03), coronary artery disease (25% vs 13%, P = .05), less prolonged AF (31 +/- 21 vs 45 +/- 30 months, P <.001), lower left ventricular ejection fraction (49 +/- 13% vs 52 +/- 9%, P = .03), and left ventricular end-diastolic dimensions (4.97 +/- 0.81 vs 4.72 +/- 0.67, P = .03). No changes in the sensing and pacing thresholds, impedance of atrial and ventricular leads, or defibrillator coil impedance after AF ablation were observed in group I. Atrial lead dislodgment was seen in two patients. Transient abnormal but "expected" pulse generator behavior was seen in 25% of patients without permanent malfunction. Stroke (1% vs 1%, P = 1.000), pulmonary vein stenosis (2% vs 1%, P = .77), and AF recurrence rates at 12 months were similar between groups I and II, respectively (19% vs 21%, P = .73). CONCLUSION: AF ablation is safe and efficacious in patients with pacemakers and defibrillators.

Atrial Fibrillation↗

PubMed2005

Relationship between successful ablation sites and the scar border zone defined by substrate mapping for ventricular tachycardia post-myocardial infarction.

INTRODUCTION: It is unknown if identification of scar border zones by electroanatomical mapping correlates with successful ablation sites determined from mapping during ventricular tachycardia (VT) post-myocardial infarction (MI). We sought to assess the relationship between successful ablation sites of hemodynamically stable post-MI VTs determined by mapping during VT with the scar border zone defined in sinus rhythm. METHODS AND RESULTS: Forty-six patients presenting with hemodynamically stable, mappable monomorphic VT post-MI and who had at least one such VT successfully ablated were prospectively included in the study. In each patient, VT was ablated by targeting regions during VT that exhibited early activation, +/- isolated mid-diastolic potentials, and concealed entrainment suggesting a critical isthmus site. Prior to ablation, a detailed sinus-rhythm CARTO voltage map of the left ventricle was obtained. A voltage <0.5 mV defined dense scar. Successful VT ablation sites were registered on the sinus voltage map to assess their relationship to the scar border zone. Of the 86 VTs, 68% were successfully ablated at sites in the endocardial border zone. The remaining VTs had ablation sites within the scar in (18%), in normal myocardium (4%), and on the epicardial surface (10%). There were no significant differences in VT recurrence amongst the different groups. CONCLUSION: Successful ablation sites of hemodynamically stable, monomorphic VTs post-MI are often located in the scar border zone as defined by substrate voltage mapping. However, in a sizable minority, ablation sites are located within endocardial scar, epicardially, and even in normal myocardium.

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PubMed2004

Relation of C-reactive protein correlates with risk of thromboembolism in patients with atrial fibrillation.

The relation between C-reactive protein, an inflammatory marker, and thromboembolic risk factors was investigated in 104 patients with atrial fibrillation and found that patients with transesophageal echocardiography identified thromboembolic risk factors had greater C-reactive protein levels than those without (1.00 vs 0.302 mg/dl). C-reactive protein also correlated with clinical stroke risk factors. Increased C-reactive protein levels were also independently associated with transesophageal echocardiographic thromboembolic risk factors.

Adult↗

PubMed2004

Mode of initiation and ablation of ventricular fibrillation storms in patients with ischemic cardiomyopathy.

OBJECTIVES: We report on the initiation of ventricular fibrillation (VF) storm in patients with ischemic cardiomyopathy (ICM) and the results of targeted ablation to treat VF storm. BACKGROUND: Monomorphic premature ventricular contractions (PVCs) have been shown to initiate VF in patients without structural heart disease. METHODS: A total of 29 patients with ICM and documented VF initiation were identified. In 21 patients, VF storm was controlled with antiarrhythmic drugs and/or treatment of heart failure. Eight patients with VF (mean 52 +/- 25 episodes) refractory to medical management required ablation. All patients underwent three-dimensional electroanatomical mapping using CARTO (Biosense-Webster Inc., Diamond Bar, California), and PVCs were mapped when present. Scarred areas were identified using voltage mapping. RESULTS: Monomorphic PVCs initiated VF in all 29 identified patients. Five of eight patients requiring ablation had frequent PVCs that allowed PVC mapping. The earliest activation site was consistently located in the scar border zone. The PVCs were always preceded by a Purkinje-like potential (PLP). Ablation was successfully performed at these sites. In three patients, infrequent PVCs prevented mapping, but PLPs were recorded around the scar border. Ablation targeting these potentials along the scar border was successfully performed. During follow-up (10 +/- 6 months), one patient had a single VF episode and another developed sustained, monomorphic ventricular tachycardia. There was no recurrence of VF storm. CONCLUSIONS: Ventricular fibrillation in ICM is triggered by monomorphic PVCs originating from the scar border zone with preceding PLPs; targeting these PVCs may prevent VF recurrence. In the absence of PVCs, both substrate mapping and ablation appear to be equally effective.

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PubMed2004

Pulmonary vein isolation for the treatment of atrial fibrillation in patients with impaired systolic function.

OBJECTIVES: We aimed to determine the safety and efficacy of pulmonary vein isolation (PVI) in atrial fibrillation (AF) patients with impaired left ventricular (LV) systolic function. BACKGROUND: To date, PVI has been performed primarily in patients with normal LV function. Yet, many AF patients have impaired LV systolic function. The outcomes of PVI in patients with impaired LV systolic function are unknown. METHODS: We included 377 consecutive patients undergoing PVI between December 2000 and January 2003. Ninety-four patients had impaired LV function (ejection fraction [EF] <40%), and they comprised the study group. The control group was the remaining 283 patients who had a normal EF. End points included AF recurrence and changes in EF and quality of life (QoL). RESULTS: Mean EF was 36% in our study group, compared with 54% in controls. After initial PVI, 73% of patients with impaired EF and 87% of patients with normal EF were free of AF recurrence at 14 +/- 6 months (p = 0.03). In the study group, there was a nonsignificant increase in EF of 4.6% and significant improvement in QoL. Complication rates were low and included a 1% risk of pulmonary vein stenosis. CONCLUSIONS: Although the AF recurrence rate after initial PVI in impaired EF patients was higher than in normal EF subjects, nearly three-fourths of patients with impaired EF remained AF-free. Although our sample size was nonrandomized, our results suggest PVI may be a feasible therapeutic option in AF patients with impaired EF. Randomized studies with more patients and longer follow-up are warranted.

Atrial Fibrillation↗

PubMed2004

Prevalence, predictors, and mortality significance of the causative arrhythmia in patients with electrical storm.

INTRODUCTION: Electrical storm (ES) is characterized by either refractory ventricular tachycardia (VT) or ventricular fibrillation (VF). However, little is known about the prevalence, predictors, and mortality implications of the causative arrhythmia in ES. We sought to assess the prevalence, predictors, and survival significance of VT and VF as the causative arrhythmia of ES in implantable cardioverter defibrillator (ICD) patients. METHODS AND RESULTS: Consecutive patients from January 2000 to December 2002 who presented to the ICD clinic with > or = 2 separate ventricular arrhythmic episodes requiring shock within 24 hours were included in the study. ICD interrogation confirmed the number of shocks and provided electrograms for interpretation of the causative arrhythmia. Patients were grouped as VF or VT according to the causative arrhythmia. Their prevalence, predictors, and mortality rates were compared. Of 2,028 patients assessed in the ICD clinic, 208 (10%) presented with ES. VF was the cause of ES in 99 of 208 patients, for an overall prevalence of 48%. Original ICD indication, coronary artery disease, and amiodarone therapy were predictive for the causative arrhythmia. There was no mortality difference between the VT and VF groups; however, both groups had significantly increased mortality compared to a control ICD population without ES. CONCLUSION: VF is the causative arrhythmia for a sizable proportion of patients with ES. The initial ICD indication, coronary artery disease, and amiodarone therapy are predictors of the causative arrhythmias in ES. There does not appear to be any mortality difference between ES patients with VT and VF, but mortality is increased in patients with ES versus control ICD patients without ES.

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PubMed2003

Randomized study comparing combined pulmonary vein-left atrial junction disconnection and cavotricuspid isthmus ablation versus pulmonary vein-left atrial junction disconnection alone in patients presenting with typical atrial flutter and atrial fibrillation.

BACKGROUND: Atrial flutter (AFL) and atrial fibrillation (AF) frequently coexist in the same patient. Recently it has been demonstrated that the triggers for both AF and AFL may originate in the pulmonary veins (PVs). We hypothesized that in patients with both AF and typical AFL, pulmonary vein-left atrial junction (PV-LAJ) disconnection may eliminate both arrhythmias. METHODS AND RESULTS: Consecutive patients with documented symptomatic AF and typical AFL were randomly assigned to have PV-LAJ disconnection combined with cavotricuspid isthmus (CTI) ablation (group 1, n=49) or PV-LAJ disconnection alone (group 2, n=59). Within the first 8 weeks after ablation, 32 of the group 2 patients had typical AFL documented, whereas none was seen in group 1. Twenty of these 32 converted to sinus rhythm after initiating antiarrhythmic drugs (AADs). Twelve were cardioverted, and AADs were started. After 8 weeks, all AADS were stopped, and only 3 patients continued to have recurrent sustained typical AFL that was eliminated by CTI ablation. Beyond 8 weeks of follow-up, 7 patients in group 1 and 6 patients in group 2 (14% and 11%, respectively) continued to have AF. Ten of these 13 patients underwent a repeat PV-LAJ disconnection procedure and were cured. The remaining 3 remained in normal sinus rhythm while taking AADs. CONCLUSIONS: In patients with both AFL and AF, PV-LAJ disconnection alone may be sufficient to control both arrhythmias. CTI block reduced early postablation recurrence of arrhythmias, which in the majority of patients reflects a short-term clinical problem.

Anti-Arrhythmia Agents↗

PubMed2003

Phased-array intracardiac echocardiography monitoring during pulmonary vein isolation in patients with atrial fibrillation: impact on outcome and complications.

BACKGROUND: The objective of this study was to assess the impact of intracardiac echocardiography (ICE) on the long-term success and complications in patients undergoing pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF). METHODS AND RESULTS: Three hundred fifteen patients underwent PVI for treatment of AF. Each patient underwent ostial isolation of all PVs using a cooled-tip ablation catheter. PVI was performed using circular mapping (CM) alone (group 1, 56 patients), CM and ICE (group 2, 107 patients), and CM and ICE with titration of radiofrequency energy based on visualization of microbubbles by ICE (group 3, 152 patients). After a mean follow-up time of 417+/-145 days, 19.6% (11 of 56), 16.8% (18 of 107), and 9.8% (15 of 152) of patients in groups 1, 2, and 3 experienced recurrence of AF, respectively. Moreover, whereas no group 3 patient experienced severe (>70%) PV stenosis, severe PV stenosis was documented in 3 (3.5%) of 56 patients in group 1 and in 2 (1.8%) of 107 patients in group 2 (P<0.05). No embolic events were detected in group 3 patients. CONCLUSIONS: Intracardiac echocardiography improves the outcome of cooled-tip PVI. Power adjustment guided by direct visualization of microbubble formation reduces the risk of PV stenosis and improves long-term cure.

Atrial Fibrillation↗