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Michael C Giudici

Publications and source records attributed to Michael C Giudici.

10 recordsLinked to original sources
PubMed2006

Diagnostic value of the 12-lead electrocardiogram during conventional and biventricular pacing for cardiac resynchronization.

The paced 12-lead ECG is a valuable tool in the assessment of patients with pacemakers, and ideally should be recorded routinely at the time of implantation and during follow-up. It has become particularly important in patients undergoing cardiac resynchronization. The multiplicity of clinical situations described in this review highlight the pitfalls of using a single ECG lead in the overall evaluation of pacemaker patients. The design of programmers capable of registering a 12-lead ECG would obviate the need of an additional electrocardiograph and encourage the routine recording of the paced 12-lead ECG with each patient encounter. Such an arrangement would improve the care of pacemaker patients.

Arrhythmias, Cardiac↗
PubMed2005

Comparison of stimulation sites within left ventricular veins on the acute hemodynamic effects of cardiac resynchronization therapy.

OBJECTIVES: The purpose of this study was to study the acute hemodynamic effect of left ventricular (LV) stimulation sites within a coronary vein. BACKGROUND: Access to LV stimulation sites for resynchronization therapy is achieved using specialized lead systems navigated through a coronary vein. The effects of stimulation in different coronary veins have been evaluated previously, but less is known about stimulation sites within a coronary vein. METHODS: Twenty-four patients (New York Heart Association functional class II-IV, age 59 +/- 10 years, ejection fraction 21 +/- 7%, QRS 166 +/- 30 ms) were enrolled in the study. A novel over-the-wire lead system was used to access an anterior or lateral coronary vein. At each lead location, a randomized stimulation protocol was executed. Hemodynamic responses were evaluated using LV dP/dtmax. RESULTS: The mean time to cannulate the coronary sinus and position the LV lead was 19 +/- 30 minutes and 17 +/- 18 minutes, respectively. Data from stimulation at two sites within a coronary vein were obtained in 19 patients (anterior vein 11; lateral vein 8). Of these patients, 14 (anterior vein 9; lateral vein 5) showed large improvement in dP/dtmax (22%-25% in anterior vein, 37%-40% in lateral vein). Overall, there were no group differences in hemodynamic effects among different stimulation sites within a coronary vein, although significant variability among sites was observed in individuals. CONCLUSIONS: Resynchronization therapy through a coronary vein improves acute hemodynamic function of heart failure patients with LV conduction disorder. There were no significant differences between basal and apical pacing sites for this group.

Aged↗
PubMed2005

Clinical results of an advanced SVT detection enhancement algorithm.

INTRODUCTION: Supraventricular tachycardia (SVT) has many characteristics that are similar to ventricular tachycardia (VT). This presents a significant challenge for the SVT-detection algorithms of an implantable cardioverter defibrillator (ICD). A newly developed ICD, which utilizes a Vector Timing and Correlation algorithm as well as interval-based conventional SVT discrimination algorithms (Rhythm ID), was evaluated in this study. MATERIALS AND METHODS: This study was a prospective, multicenter trial that evaluated 96 patients implanted with an ICD at 21 U.S. centers. All patients were followed at 2 weeks, 1 month, and every 3 months post implant. A manual Rhythm ID reference vector was acquired prior to any arrhythmia induction. During testing, atrial tachyarrhythmias were induced first, followed by ventricular arrhythmia induction. Induced and spontaneous SVT and VT/ventricular fibrillation (VF) episodes recorded during the trial were annotated by physician investigators. RESULTS: The mean age of the patients implanted with an ICD was 67.3 +/- 10.8 years. Eighty-one percent of patients were male. The primary cardiovascular disease was coronary artery disease, and the primary tachyarrhythmia was monomorphic VT. Implementation of the Rhythm ID algorithm did not affect the VT/VF detection time. There were a total of 370 ventricular tachyarrhythmias (277 induced and 93 spontaneous) and 441 SVT episodes (168 induced and 273 spontaneous). Sensitivity for ventricular tachyarrhythmias was 100%, and specificity for SVT was 92% (94% and 91% for induced and spontaneous SVT, respectively). All patients had a successful manual Rhythm ID acquisition prior to atrial tachyarrhythmia induction. At the 1-month follow-up, the Rhythm ID references were updated automatically an average of 167.8 +/- 122.7 times. Stored Rhythm ID references correlated to patients' normally conducted rhythm 100% at 2 weeks, and 98% at 1 month. CONCLUSIONS: The Rhythm ID algorithm achieved 100% sensitivity for VT/VF, and 92% specificity for SVT. The manual and automatic Rhythm ID update algorithms successfully acquired references, and the updated references were highly accurate.

Aged↗
PubMed2004

Pacemaker and implantable cardioverter defibrillator implantation without reversal of warfarin therapy.

The study evaluated all patients undergoing permanent pacemaker and ICD implantation over a 4-year period to determine if anticoagulated patients required normalization of coagulation factors in the periprocedural period. The study included 1,025 (597 men, 428 women, age 24-100 years, mean 72 years) consecutive patients who underwent device implantation using mostly a percutaneous subclavian approach. The procedures were performed without reversal of anticoagulation in 470 patients with INRs >or= 1.5 at the time of the procedure (mean INR 2.6 +/- 1.0, range 1.5-7.5). The complication rate in the anticoagulated group was similar to those in patients with a normal INR. Routine normalization of coagulation factors prior to pacemaker/ICD placement may not be necessary.

Adult↗
PubMed2004

Right ventricular outflow tract placement of defibrillation leads: five year experience.

Over a 5-year period, 112 patients (89 male/23 female, mean age 65 years) underwent right ventricular outflow tract (RVOT) placement of permanent active-fixation transvenous pacing/defibrillating leads. At implantation, the pacing threshold was 0.6 +/- 0.3 V at 0.5 ms pulse duration and R wave amplitude was 10.9 +/- 4.9 mV. The defibrillation threshold (DFT) of right-sided implants was 17.7 +/- 3.4 J while that of left-sided implants was 16.1 +/- 3.3 J. Patients were followed at 1 and 3 month postimplant and at six-month intervals thereafter. At mean follow-up of 22.5 +/- 17.5 months (range 1-47 months) there were no lead dislodgments, unsuccessful shock therapies, or failure to sense or pace for bradycardia or tachycardia. Death was not sudden in the 17 patients who died. We conclude that RVOT pacing-defibrillation lead implantation is safe, efficacious, and potentially attractive because preliminary evidence suggests that it may not be associated with the adverse hemodynamic effects of pacing at the right ventricular apex.

Adult↗
PubMed2003

Cardiac resynchronization therapy for the treatment of heart failure in patients with intraventricular conduction delay and malignant ventricular tachyarrhythmias.

OBJECTIVES: This study was conducted to assess the safety and effectiveness of cardiac resynchronization therapy (CRT) when combined with an implantable cardioverter defibrillator (ICD). BACKGROUND: Long-term outcome of CRT was measured in patients with symptomatic heart failure (HF), intraventricular conduction delay, and malignant ventricular tachyarrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]) requiring therapy from an ICD. METHODS: Patients (n = 490) were implanted with a device capable of providing both CRT and ICD therapy and randomized to CRT (n = 245) or control (no CRT, n = 245) for up to six months. The primary end point was progression of HF, defined as all-cause mortality, hospitalization for HF, and VT/VF requiring device intervention. Secondary end points included peak oxygen consumption (VO(2)), 6-min walk (6 MW), New York Heart Association (NYHA) class, quality of life (QOL), and echocardiographic analysis. RESULTS: A 15% reduction in HF progression was observed, but this was statistically insignificant (p = 0.35). The CRT, however, significantly improved peak VO(2) (0.8 ml/kg/min vs. 0.0 ml/kg/min, p = 0.030) and 6 MW (35 m vs. 15 m, p = 0.043). Changes in NYHA class (p = 0.10) and QOL (p = 0.40) were not statistically significant. The CRT demonstrated significant reductions in ventricular dimensions (left ventricular internal diameter in diastole = -3.4 mm vs. -0.3 mm, p < 0.001 and left ventricular internal diameter in systole = -4.0 mm vs. -0.7 mm, p < 0.001) and improvement in left ventricular ejection fraction (5.1% vs. 2.8%, p = 0.020). A subgroup of patients with advanced HF (NYHA class III/IV) consistently demonstrated improvement across all functional status end points. CONCLUSIONS: The CRT improved functional status in patients indicated for an ICD who also have symptomatic HF and intraventricular conduction delay.

Aged↗