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Mitchell N Faddis

Publications and source records attributed to Mitchell N Faddis.

14 recordsLinked to original sources
PubMed2006

Relation of left ventricular lead placement in cardiac resynchronization therapy to left ventricular reverse remodeling and to diastolic dyssynchrony.

The effects of left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT) on LV remodeling and dyssynchrony are not well defined. Sixty-one patients (age 60 +/- 11 years, 76% men) were evaluated by echocardiography before and 4 +/- 2 months after CRT and grouped by the LV lead placement (lateral, posterolateral, or anterolateral). Echocardiographic measurements included LV volumes and LV ejection fraction. Tissue Doppler imaging was used to assess for inter- and intraventricular systolic and diastolic dyssynchrony. Analysis of variance was used to determine the effect of the LV lead placement on echocardiographic variables after CRT. The LV lead was placed in a lateral cardiac vein in 33 patients (54%), posterolateral in 15 (25%), and anterior in 13 (21%). Lateral LV lead placement was associated with significantly smaller LV volumes compared with the posterolateral lead placement (p <0.01). Diastolic dyssynchrony improved significantly with lateral lead placement compared with the anterior lead location (p <0.05). Improvement in LV ejection fraction and inter- and intraventricular systolic dyssynchrony was similar among the 3 groups. In conclusion, in patients undergoing CRT, a lateral lead location resulted in greater reverse LV remodeling and improved diastolic dyssynchrony compared with other lead placement locations.

Diastole↗
PubMed2006

Clinical outcomes after cardiac resynchronization therapy: importance of left ventricular diastolic function and origin of heart failure.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves functional outcomes in patients with severe systolic heart failure. Whether the effects of CRT on left ventricular (LV) diastolic function and clinical outcomes are influenced by the cause as either ischemic or nonischemic cardiomyopathy (CM) has not been well established. METHODS: A total of 57 patients (age 60 +/- 11 years; 25% women; LV ejection fraction 25 +/- 5%) were studied before and 4 +/- 2 months after CRT by echocardiography. Heart failure cause was ischemic CM in 19 and nonischemic CM in 38. Measurements of LV systolic and diastolic function were determined by 2-dimensional and Doppler echocardiography with Doppler tissue imaging of regional myocardial velocities. Clinical outcome events were assessed at long-term follow-up and included hospitalization for heart failure exacerbation, heart transplantation, or cardiac-related death. RESULTS: There were significant increases in LV ejection fraction, reductions in end-systolic volumes, and improved LV systolic dyssynchrony in both groups. However, significant improvements in LV diastolic function were observed only in the patients with nonischemic CM. Clinical events occurred in 53% of the ischemic group versus 26% of the nonischemic group (P < .05) after 20 +/- 11 months of CRT. Univariate and multivariate analysis revealed that Doppler-estimated LV filling pressures were predictors of clinical outcome events. CONCLUSIONS: After CRT patients with ischemic CM exhibit lack of improvement in LV diastolic function despite favorable effects on LV systolic performance. The Doppler-derived LV filling indices may be an important predictor of long-term clinical outcomes after CRT.

Cardiac Pacing, Artificial↗
PubMed2006

Prospective comparison of echocardiographic atrioventricular delay optimization methods for cardiac resynchronization therapy.

BACKGROUND: Atrioventricular (AV) delay optimization can be an important determinant of the response to cardiac resynchronization therapy (CRT) in patients with medically refractory heart failure and a ventricular conduction delay. OBJECTIVES: The purpose of this study was to compare two Doppler echocardiographic methods of AV delay optimization after CRT. METHODS: Forty consecutive patients (age 59 +/- 12 years) with severe heart failure, New York Heart Association class 3.1 +/- 0.4, QRS duration 177 +/- 23 ms, and left ventricular ejection fraction 26% +/- 6% referred for CRT were studied using two-dimensional Doppler echocardiography. In each patient, the acute improvement in stroke volume with CRT in response to two methods of AV delay optimization was compared. In the first method, the AV delay that produced the largest increase in the aortic velocity time integral (VTI) derived from continuous-wave Doppler (aortic VTI method) was measured. In the second method, the AV delay that optimized the timing of mitral valve closure to occur simultaneously with the onset of left ventricular systole was calculated from pulsed Doppler mitral waveforms at a short and long AV delay interval (mitral inflow method). RESULTS: The optimized AV delay determined by the aortic VTI method resulted in an increase in aortic VTI of 19% +/- 13% compared with an increase of 12% +/- 12% by the mitral inflow method (P <.001). The optimized AV delay by the aortic VTI method was significantly longer than the optimized AV delay calculated from the mitral inflow method (119 +/- 34 ms vs 95 +/- 24 ms, P <.001). There was no correlation in the AV delay determined by the two methods (r = 0.03). CONCLUSION: AV delay optimization by Doppler echocardiography for patients with severe heart failure treated with a CRT device yields a greater systolic improvement when guided by the aortic VTI method compared with the mitral inflow method.

Atrioventricular Node↗
PubMed2006

Radiofrequency ablation of atrioventricular nodal reentrant tachycardia using a novel magnetic guidance system compared with a conventional approach.

BACKGROUND: A novel magnetic guidance system has been developed that allows the operator to remotely navigate an electrophysiology mapping/ablation catheter to precise locations in the heart for treatment of tachyarrhythmias. To date, this new technology has not been directly compared with the conventional approach. OBJECTIVE: To compare the use of the magnetic guidance system to the conventional approach for ablation of atrioventricular nodal reentry tachycardia. METHODS: Between November 2002 and October 2004, 28 patients with atrioventricular nodal reentry tachycardia treated with the magnetic guidance system were retrospectively compared with 28 matched control patients. RESULTS: Patients treated using the magnetic guidance system had similar procedure durations and fluoroscopy times compared with the matched controls. The only statistically significant difference between the groups was a longer time between insertion of the ablation catheter and placement of the first radiofrequency lesion in the magnetic guidance system cohort (23.3 +/- 12.0 vs. 10.5 +/- 13.9, p=0.001), possibly due to the research protocol. However, there was a trend toward a shorter total time that radiofrequency energy was applied in the magnetic guidance system cohort (5.2 +/- 4.5 vs. 8.0 +/- 7.2, p=0.087). There were no major complications or recurrences after at least 3 months of follow-up among the patients treated with the magnetic guidance system. CONCLUSION: The magnetic guidance system appears to have similar, and possibly improved, clinical efficacy compared with conventional catheter navigation for the treatment of atrioventricular nodal reentrant tachycardia.

Adolescent↗
PubMed2006

Smokers are at markedly increased risk of appropriate defibrillator shocks in a primary prevention population.

BACKGROUND: Cigarette smoking is a known risk factor for sudden cardiac death (SCD). It is unknown whether smoking status affects implantable cardioverter-defibrillator (ICD) therapy. OBJECTIVE: The primary end point was appropriate ICD therapy according to smoking status. METHODS: A total of 105 consecutive patients who underwent ICD implantation for primary prevention of SCD were retrospectively analyzed. All patients had an abnormal response to programmed ventricular stimulation performed for nonsustained ventricular tachycardia in the setting of ischemic cardiomyopathy between January 1999 and December 2003. RESULTS: Among the 105 patients, 6 (37.5%) of 16 current smokers, 14 (25.9%) of 54 former smokers, and 2 (5.7%) of 35 of never smokers received an appropriate ICD therapy (P = .02). Kaplan-Meier analysis for survival free of appropriate ICD therapy comparing never smokers with both current smokers (P = .002) and former smokers (P = .01) demonstrated statistically significant differences by log rank over a mean follow-up of 21.8 +/- 13.7 months. Cox regression analysis found that current smoking was associated with an increased risk of appropriate therapy (hazard ratio 7.36; 95% confidence interval 1.42-38.10; P = .02) as was former smoking (hazard ratio 5.42; 95% confidence interval 1.20-24.47; P = .03). There was no difference in inappropriate therapy between groups (P = .12). CONCLUSIONS: Cigarette smoking is an independent predictor of appropriate ICD therapy in a primary prevention population. While outcomes differences among current smokers, former smokers, and never smokers are demonstrable, the effect of smoking cessation on ICD therapy requires further study.

Aged↗
PubMed2005

Improvements in left ventricular diastolic function after cardiac resynchronization therapy are coupled to response in systolic performance.

OBJECTIVES: To determine the short-term effects of cardiac resynchronization therapy (CRT) on measurements of left ventricular (LV) diastolic function in patients with severe heart failure. BACKGROUND: Cardiac resynchronization therapy improves systolic performance; however, the effects on diastolic function by load-dependent pulsed-wave Doppler transmitral indices has been variable. METHODS: Fifty patients with severe heart failure were evaluated by two-dimensional Doppler echocardiography immediately prior to and 4 +/- 1 month after CRT. Measurements included LV volumes and ejection fraction (EF), pulsed-wave Doppler (PWD)-derived transmitral filling indices (E- and A-wave velocities, E/A ratio, deceleration time [DT], diastolic filling time [DFT], and isovolumic relaxation time). Tissue Doppler imaging was used for measurements of systolic and diastolic (Em) velocities at four mitral annular sites; mitral E-wave/Em ratio was calculated to estimate LV filling pressure. Color M-mode flow propagation velocities were also obtained. RESULTS: After CRT, LV volumes decreased significantly (p < 0.001) and LVEF increased >5% in 28 of 50 patients (56%) and were accompanied by reduction in PWD mitral E-wave velocity and E/A ratio (both p < 0.01), increased DT and DFT (both p < 0.01), and lower filling pressures (i.e., E-wave/Em septal; p < 0.01). Patients with LVEF response < or =5% after CRT had no significant changes in measurements of diastolic function; LV relaxation (i.e., Em velocities) worsened in this group. CONCLUSIONS: In heart failure patients receiving CRT, improvement in LV diastolic function is coupled to the improvement in LV systolic function.

Aged↗
PubMed2005

Cardiac resynchronization therapy acutely improves diastolic function.

BACKGROUND: Invasive studies have shown that cardiac resynchronization therapy (CRT) acutely improves left ventricular (LV) systolic performance and lowers filling pressures in a majority of patients with medically-refractory severe heart failure. Measurements included LV volume, ejection fraction, PWD early (E-wave) and atrial (A-wave) velocities, diastolic filling time (DFT), and DTI early diastolic mitral annular velocity (Em) at the lateral and septal annulus; PWD mitral E-wave/Em and E/FP were calculated to estimate LV filling pressures. RESULTS: Immediately after CRT, LV volumes decreased and LVEF increased significantly. PWD mitral E-wave velocity decreased and E-wave duration and DFT increased significantly; mitral E/FP ratio also decreased significantly, consistent with a decrease in LV filling pressure. Patients with a pre-CRT mitral E/A ratio >1 (n = 20), demonstrated improvements in LV diastolic filling and lower filling pressures whereas those with an E/A ratio < or =1 (n = 21) did not show significant changes in diastolic indices. CONCLUSIONS: The acute effects of CRT include echocardiographic evidence of reduced LV volumes and increased LVEF with improved diastolic filling and lower filling pressures; LV relaxation is not significantly altered. The benefits in diastolic function are dependent on the PWD-determined LV filling characteristics prior to CRT.

Cardiac Pacing, Artificial↗
PubMed2005

Implantable cardioverter-defibrillator therapy improves long-term survival in patients with unexplained syncope, cardiomyopathy, and a negative electrophysiologic study.

OBJECTIVES: The purpose of this study was to evaluate the long-term outcomes of patients with unexplained syncope, ischemic or nonischemic cardiomyopathy, and a negative electrophysiologic study (EPS). BACKGROUND: EPS is frequently performed to evaluate syncope in patients with left ventricular dysfunction. Limited long-term data evaluating all-cause mortality in patients with no inducible arrhythmia or examining the potential benefits from implantable cardioverter-defibrillator (ICD) therapy are available. METHODS: We evaluated 102 consecutive patients with unexplained syncope, cardiomyopathy, and a negative EPS from September 1996 to December 2000. A blinded matched case-control analysis utilized 51 of these patients (19 treated with an ICD and 32 matched controls treated with conventional therapy). We compared primary endpoint of death and documented cardiac arrest of patients treated with ICD therapy to matched controls. RESULTS: Baseline characteristics were similar between groups. There were 14 primary events among the study population during a follow-up period of 44.3 +/- 20 months: 2 in the ICD group and 12 in the conventional therapy group. The hazard ratio for the risk of event in the ICD group compared with the conventional therapy group was 0.18 (95% confidence interval, 0.04-0.85; P = .04). Other comorbid conditions, including age, sex, ischemic etiology of heart failure, ejection fraction, and antiarrhythmic use, did not predict outcome. Appropriate ICD shocks occurred in 26% of patients at 2 years. CONCLUSIONS: This study suggests that empiric ICD therapy improves long-term outcomes in patients with unexplained syncope, ischemic or nonischemic cardiomyopathy, and negative EPS.

Aged↗
PubMed2004

Randomized prospective trial of atrioventricular delay programming for cardiac resynchronization therapy.

OBJECTIVES: The purpose of this study was to determine if AV delay optimization with continuous-wave Doppler aortic velocity-time integral (VTI) is clinically superior to an empiric program in patients treated with cardiac resynchronization therapy (CRT) for severe heart failure. BACKGROUND: The impact of AV delay programming on clinical outcomes associated with CRT is unknown. METHODS: A randomized, prospective, single-blind clinical trial was performed to compare two methods of AV delay programming in 40 patients with severe heart failure referred for CRT. Patients were randomized to either an optimized AV delay determined by Doppler echocardiography (group 1, n = 20) or an empiric AV delay of 120 ms (group 2, n = 20) with both groups programmed in the atriosynchronous biventricular pacing (VDD) mode. Optimal AV delay was defined as the AV delay that yielded the largest aortic VTI at one of eight tested AV intervals (between 60 and 200 ms). New York Heart Association (NYHA) functional classification and quality-of-life (QOL) score were compared 3 months after randomization. RESULTS: Immediately after CRT initiation with AV delay programming, VTI improved by 4.0 +/- 1.7 cm vs 1.8 +/- 3.6 cm (P < .02), and ejection fraction (EF) increased by 7.8 +/- 6.2% vs 3.4 +/- 4.4% (P < .02) in group 1 vs group 2, respectively. After 3 months, NYHA classification improved by 1.0 +/- 0.5 vs 0.4 +/- 0.6 class points (P < .01), and QOL score improved by 23 +/- 13 versus 13 +/- 11 points (P < .03) for group 1 vs group 2, respectively. CONCLUSIONS: Echocardiography-guided AV delay optimization using the aortic Doppler VTI improves clinical outcomes at 3 months compared to an empiric AV delay program of 120 ms.

Atrioventricular Node↗
PubMed2003

Magnetic guidance system for cardiac electrophysiology: a prospective trial of safety and efficacy in humans.

OBJECTIVES: We evaluated in humans the safety and efficacy of a novel magnetic guidance system (MGS) for electrophysiological mapping, pacing, and ablation. BACKGROUND: Catheter ablation of atrial fibrillation and other complex arrhythmias requires precise catheter manipulation and stabilization. We have shown in animals that the MGS can precisely manipulate a mapping catheter within the heart with an external magnetic field rather than manual catheter control. METHODS: Thirty-one adults referred for diagnostic electrophysiology studies were enrolled in a prospective trial of the MGS. The magnetic catheter was navigated to preselected sites in the right atrium (RA) and right ventricle (RV) in the first 20 patients. Electrograms were recorded at each target site, and pacing thresholds were measured. In a subset of five patients, RA and RV electrograms and stimulation thresholds were recorded with both a standard ablation catheter and the magnetic catheter. Eleven additional patients were recruited for supraventricular tachycardia (SVT) mapping, and seven of these underwent ablation. RESULTS: Navigation was successful in 200 of 202 predetermined right-sided navigation targets and 13 of 13 targets in the left atria. Pacing thresholds and electrogram amplitudes in the RA and RV were not significantly different between the standard and magnetic catheters. The SVT mapping with the magnetic catheter was successful in 13 patients, including 4 with left-sided accessory pathways. The MGS was used for successful ablation of SVT in seven of seven patients. There were no procedural complications. CONCLUSIONS: These results demonstrate that the MGS can be used for intracardiac mapping, pacing, and ablation safely and effectively.

Adult↗
PubMed2002

Novel, magnetically guided catheter for endocardial mapping and radiofrequency catheter ablation.

BACKGROUND: Ablation of complex arrhythmias would be greatly facilitated by more precise control of ablation catheters. A feasibility study was performed in animals to evaluate a novel magnetic guidance system (MGS) that generates a magnetic field to control the movement and position of a magnetic ablation catheter. METHODS AND RESULTS: The MGS is composed of a digital biplanar fluoroscope within an array of superconducting electromagnets that surround the torso of the experimental animal and a computer control system that generates a composite magnetic field for directional catheter deflection. Magnetic catheter navigation was performed in dogs and pigs (20 to 30 kg). A 7F magnetic ablation catheter was used for intracardiac navigation and radiofrequency ablation. The performance of a standard 7F deflectable catheter was not affected by the MGS. The magnetic catheter was navigated successfully to 51 predefined targets throughout the heart in 6 animals. In 5 animals, the magnetic catheter, guided by a 3D computed tomogram, was successfully navigated to all pulmonary veins. Navigation accuracy was estimated as <1 mm displacement from the target. The magnetic catheter was used to ablate the atrioventricular node in 4 animals and to perform linear ablations across the endocardial surface underlying an epicardial multielectrode recording plaque in 4 animals. CONCLUSIONS: These results demonstrate that the MGS can navigate and stabilize an ablation catheter at endocardial targets. Linear or focal radiofrequency ablation with the magnetic catheter is not compromised by the magnetic field. This technology provides precise control of endocardial catheters.

Animals↗
PubMed2002

Pacing interventions for falls and syncope in the elderly.

There is a high prevalence of cardiovascular disorders among elderly patients with recurrent falls or syncope, and cardiovascular causes are implicated in a significant proportion of three cases. Common cardiovascular causes of falls and syncope include carotid sinus syndrome, vasovagal episodes, sick sinus syndrome, and atrioventricular block. A comprehensive history and physical examination supplemented by electrocardiographic monitoring, carotid sinus massage, and tilt-table testing in appropriately selected patients form the basis of the diagnostic evaluation to exclude a significant cardiovascular disorder. Patients with documented symptomatic bradycardia often benefit from pacemaker implantation, as evidenced by a reduction in recurrent events and improved quality of life. Although dual-chamber pacemakers, particularly those with rate responsiveness, provide more physiologic pacing than single-chamber ventricular devices, the superiority of dual-chamber pacemakers in reducing major clinical events has not been demonstrated. The efficacy of an aggressive evaluation and patient-management strategy that includes pacemaker implantation for elderly patients with recurrent falls has been validated only by one prospective clinical trial; however, available data are compelling. For a variety of cardiovascular conditions, permanent pacemaker implantation has a demonstrated efficacy to prevent symptoms that arise from transient hypotension and decreased cerebral perfusion. The implication of these data is that many falls may be preventable through permanent pacemaker implantation in appropriately selected patients.

Accidental Falls↗