Christian Machado

Prospective Randomized Multicenter Trial of Empirical Antitachycardia Pacing Versus Shocks for Spontaneous Rapid Ventricular Tachycardia in Patients With Implantable Cardioverter-Defibrillators Pacing Fast Ventricular Tachycardia Reduces Shock Therapies (PainFREE Rx II) Trial Results

Background—Successful antitachycardia pacing (ATP) terminates ventricular tachycardia (VT) up to 250 bpm without the need for painful shocks in implantable cardioverter-defibrillator (ICD) patients. Fast VT (FVT) >200 bpm is often treated by shock because of safety concerns, however. This prospective, randomized, multicenter trial compares the safety and utility of empirical ATP with shocks for FVT in a broad ICD population. Methods and Results—We randomized 634 ICD patients to 2 arms—standardized empirical ATP (n=313) or shock (n=321)—for initial therapy of spontaneous FVT. ICDs were programmed to detect FVT when 18 of 24 intervals were 188 to 250 bpm and 0 of the last 8 intervals were >250 bpm. Initial FVT therapy was ATP (8 pulses, 88% of FVT cycle length) or shock at 10 J above the defibrillation threshold. Syncope and arrhythmic symptoms were collected through patient diaries and interviews. In 11±3 months of follow-up, 431 episodes of FVT occurred in 98 patients, representing 32% of ventricular tachyarrhythmias and 76% of those that would be detected as ventricular fibrillation and shocked with traditional ICD programming. ATP was effective in 229 of 284 episodes in the ATP arm (81%, 72% adjusted). Acceleration, episode duration, syncope, and sudden death were similar between arms. Quality of life, measured with the SF-36, improved in patients with FVT in both arms but more so in the ATP arm. Conclusions—Compared with shocks, empirical ATP for FVT is highly effective, is equally safe, and improves quality of life. ATP may be the preferred FVT therapy in most ICD patients.

Effectiveness of Implantable Cardioverter- Defibrillators for the Primary Prevention of Sudden Cardiac Death in Women With Advanced Heart Failure A Meta-analysis of Randomized Controlled Trials

BACKGROUND Numerous clinical trials have established a role for implantable cardioverter-defibrillators in the prevention of sudden cardiac death in patients with heart failure. However, questions remain that regard the clinical benefit of these therapies in different patient subgroups. Specifically, the role of implantable cardioverter-defibrillators in women with heart failure for the primary prevention of sudden cardiac death has not been well established. Our objective is to determine whether implantable cardioverter-defibrillators reduce mortality in women with advanced heart failure. METHODS We searched MEDLINE (1950-2008), EMBASE (1988-2008, week 24), the Cochrane Controlled Trials Register (third quarter, 2008), the National Institute of Health ClinicalTrials.gov database, the Food and Drug Administration Web site, and various reports presented at scientific meetings (1994-2007). Eligible studies were randomized controlled trials of implantable cardioverter/defibrillators for the primary prevention of sudden cardiac death in patients with heart failure that reported all-cause mortality as an outcome for the female population. Of the 2619 reports identified, 5 trials that enroll 934 women were included in the meta-analysis. RESULTS Pooled data from the 5 trials revealed no statistically significant decrease in all-cause mortality in women with heart failure who receive implantable cardioverter-defibrillators (hazard ratio, 1.01; 95% confidence interval, 0.76-1.33). CONCLUSIONS Implantable cardioverter-defibrillator therapy for the primary prevention of sudden cardiac death in women does not reduce all-cause mortality. Further studies are needed to investigate the reasons for this ob servation and to define the population of women who may benefit most from implantable cardioverter-defibrillator therapy.

Probucol-associated tachyarrhythmic events and QT prolongation: Importance of gender

From published articles and adverse reactions reports filed with the FDA (available through the Freedom of Information Act), we analyzed occurrences of tachyarrhythmias and the magnitude of QTc prolongation associated with probucol therapy. Of 16 cases of tachyarrhythmic events reported in association with probucol, 15 (94%) occurred in women (p < 0.01 vs expected value of 58%). Tachyarrhythmias were specifically described as TdP in 11 (63%) cases, all women; additional potential contributory QT-prolonging factors (besides probucol) were not identifiable in 2 of the 11 cases. We also analyzed QTc responses in 359 probucol-treated patients, all having baseline QTc < or = 0.44 sec1/2. At doses of 500 to 1000 mg/day, probucol-associated prolongation of QTc to values > or = 0.45 sec1/2 was observed in 22% of women versus 7% of men (p < 0.001) and to values > or = 0.47 sec1/2 in 8% of women versus 2% of men (p < 0.03). Multivariate analysis identified baseline QTc (p < 0.0001) and female gender (p < 0.03), but neither age nor dose, as significant independent predictors of QTc prolongation to > or = 0.45 sec1/2 with probucol. These findings have relevance to the clinical use of probucol, provide further evidence that women have a relatively greater predisposition to development of acquired long QT syndrome, and carry implications for the design of trials involving QT-prolonging drugs.

A protocol for patients with cardiovascular implantable devices undergoing magnetic resonance imaging (MRI): should defibrillation threshold testing be performed post-(MRI)

PurposeMagnetic resonance imaging (MRI) in patients with Cardiovascular Implantable Electronic Devices (CIED) has not been approved by the Food and Drug Administration. Recent data suggests MRI as a relative rather than absolute contraindication in CIED patients. Recently, the American Heart Association has recommended defibrillation threshold testing (DFTT) in implantable cardioverter defibrillator (ICD) patients undergoing MRI. We evaluated the feasibility and safety of a protocol for MRI in CIED patients, incorporating the new recommendations on DFTT.MethodsConsecutive patients with CIED undergoing MRI were included. The protocol consisted of continuous monitoring during imaging, device interrogation pre- and post-MRI, reprogramming of the pacemaker to an asynchronous mode in pacemaker-dependent (PMD) patients and a non-tracking/sensing mode for non-PMD patients. All tachyarrhythmia therapies were disabled. Devices were interrogated for lead impedance, battery life, pacing, and sensing thresholds. All patients with ICD underwent DFTT/defibrillator safety margin testing (DSMT) post-MRI.ResultsA total of 92 MRI’s at 1.5 Tesla were performed in 38 patients. A total of 13 PMD patients, ten ICD patients, four cardiac resynchronization therapy with defibrillator (CRT-D) patients, and 11 non-PMD patients were scanned from four major manufacturers. No device circuitry damage, programming alterations, inappropriate shocks, failure to pace, or changes in sensing, pacing, or defibrillator thresholds were found on single or multiple MRI sessions.ConclusionsOur protocol for MRI in CIED patients appears safe, feasible, and reproducible. This is irrespective of the type of CIED, pacemaker dependancy or multiple 24-h scanning sessions. Our protocol addresses early detection of potential complications and establishes a response system for potential device-related complications. Our observation suggests that routine DFTT/DSMT post-MRI may not be necessary.

Pacemaker Reuse An Initiative to Alleviate the Burden of Symptomatic Bradyarrhythmia in Impoverished Nations Around the World

> Health of body and mind is so fundamental to the good life that if we believe men have any personal rights at all as human beings, they have an absolute right to such a measure of good health as society and society alone is able to give them. > > —Aristotle, 330 bc For most of the industrialized world, the morbidity and mortality attributed to cardiovascular disease have declined in recent decades as a result of improvements in technology and a greater emphasis on primary and secondary preventative strategies.1 Unfortunately, this dramatic improvement in disease burden has not been witnessed in low- and middle-income countries (LMICs), defined by the World Bank as generating a gross national income per capita lower than US

Torsade de pointes as a complication of subarachnoid hemorrhage: A critical reappraisal

9200.2 Currently, cardiovascular disease is the primary cause of mortality worldwide, accounting for 30% of all global deaths,3 and it has twice the mortality rate of HIV/AIDS, malaria, and tuberculosis combined.4 Secondary treatments are often limited because of a paucity of skilled healthcare providers and, more important, the inability of the patient to afford costly medical procedures.5 This great disparity in medical health care is clearly evident in the field of cardiac electrophysiology, specifically pacemaker implantation; this specialty is either severely underdeveloped or entirely nonexistent in many LMICs.6 As a result, many individuals with symptomatic bradycardia experience a decreased quality of life and/or decreased life expectancy because of a lack of resources (personal correspondence, University of Philippines–Philippine General Hospital [UP-PGH], November 15, 2008). As the epidemic of cardiovascular disease continues to alter the demographics of disease in LMICs, healthcare providers with access to medical technology must investigate novel methods of easing the burden of those less fortunate. The purpose of this article is to address the concept of postmortem pacemaker use for those in LMICs who otherwise …

Pacemaker Patient‐Triggered Event Recording: Accuracy, Utility, and Cost for the Pacemaker Follow‐Up Clinic

Subarachnoid hemorrhage is widely accepted as a potential cause of torsade de pointes (TdP), yet this putative etiologic relationship has never been systematically evaluated. We therefore undertook a MEDLINE search from 1966 through 1993, with relevant back referencing, and identified 20 cases of TdP in the setting of subarachnoid hemorrhage. It was impossible in any of these cases (usually because of insufficient data) to completely exclude one or more alternative explanations for TdP, including congenital long QT syndrome, hypokalemia, hypomagnesemia, or drug-induced QT prolongation. Furthermore, of a total of 1,139 patients in 16 prospective series of subarachnoid hemorrhage with electrographic analyses, there were only five reported cases of TdP, all in patients with hypokalemia. Thus, extremely limited scientific data exist to support the notion that subarachnoid hemorrhage can be a distinct cause of TdP. Until more definitive evidence is available, the development of TdP in patients with subarachnoid hemorrhage is probably better characterized as a multifactorial phenomenon occurring in an acute, typically intensive care, setting.

Response to the Center for Medicare & Medicaid Services coverage with evidence development request for primary prevention implantable cardioverter-defibrillators: Data from the OMNI study

Many pacemaker patients have vague symptoms following implantation. It is often difficult for the physician to ascertain if they are cardiac in origin. A new pacemaker feature has been introduced, Patient‐Triggered Event Records (PTER), to help the physician with this diagnosis. The PTEB is a continuously running event record which stores the cardiac rhythm and rate. Brief application of a magnet will transfer the record into the devices memory. The data recorded will be the 97 events prior to the magnet application and the 30 events following magnet removal. The exact state of pacing (atrial and ventricular sensing/pacing, or premature ventricular events) and the rate of the ventricular events will be graphically displayed by the programmer for all 127 events. Thus, the exact pacer and cardiac rhythm can be determined during the period of the symptomatic episode. A total of three PTERs can be stored within the device. If a fourth is recorded, it will replace the oldest record. Three pacemakers with the PTER feature were tested in vitro with five different simulated cardiac rhythms, A beat‐by‐beat comparison between the PTER and the 15 simulated test rhythms revealed a 100% accurate documentation by PTER. Sixteen pacemaker patients which have the PTER feature were monitored using a King of Hearts™ for a total of 43 symptomatic events. The PTER records produced clinically relevant information 98% of the time while the King of Hearts™ produced clinically relevant information 81 % of the time. A comparison of costs of the two different methods of monitoring these patients, was

Safety, Efficacy, and Performance of Implanted Recycled Cardiac Rhythm Management (CRM) Devices in Underprivileged Patients

2,432 versus

Thrombus formation at the site of radiofrequency catheter ablation.

4.480 for the PTER and loop event monitor respectively. The PTER is an accurate, lower cost method for monitoring and diagnosing symptomatic pacemaker patients. The PTER can be used as the first diagnostic tool in troubleshooting patients with paroxysmal symptoms in the pacemaker clinic population.