Carlos Rizo-Patron

Quality of life and clinical outcomes in elderly patients treated with ventricular pacing as compared with dual-chamber pacing

BACKGROUND: Standard clinical practice permits the use of either single-chamber ventricular pacemakers or dual-chamber pacemakers for most patients who require cardiac pacing. Ventricular pacemakers are less expensive, but dual-chamber pacemakers are believed to be more physiologic. However, it is not known whether either type of pacemaker results in superior clinical outcomes. METHODS: The Pacemaker Selection in the Elderly study was a 30-month, single-blind, randomized, controlled comparison of ventricular pacing and dual-chamber pacing in 407 patients 65 years of age or older in 29 centers. Patients received a dual-chamber pacemaker that had been randomly programmed to either ventricular pacing or dual-chamber pacing. The primary end point was health-related quality of life as measured by the 36-item Medical Outcomes Study Short-Form General Health Survey. RESULT: The average age of the patients was 76 years (range, 65 to 96), and 60 percent were men. Quality of life improved significantly after pacemaker implantation (P<0.001), but there were no differences between the two pacing modes in either the quality of life or prespecified clinical outcomes (including cardiovascular events or death). However, 53 patients assigned to ventricular pacing (26 percent) were crossed over to dual-chamber pacing because of symptoms related to the pacemaker syndrome. Patients with sinus-node dysfunction, but not those with atrioventricular block, had moderately better quality of life and cardiovascular functional status with dual-chamber pacing than with ventricular pacing. Trends of borderline statistical significance in clinical end points favoring dual-chamber pacing were observed in patients with sinus-node dysfunction, but not in those with atrioventricular block. CONCLUSION: The implantation of a permanent pacemaker improves health-related quality of life. However, the quality-of-life benefits associated with dual-chamber pacing as compared with ventricular pacing are observed principally in the subgroup of patients with sinus-node dysfunction.

Radiofrequency catheter ablation for management of symptomatic ventricular ectopic activity

OBJECTIVES This study assessed the useful role of intracardiac mapping and radiofrequency catheter ablation in eliminating drug-refractory monomorphic ventricular ectopic beats in severely symptomatic patients. BACKGROUND Ventricular ectopic activity is commonly encountered in clinical practice. Usually, it is not associated with life-threatening consequences in the absence of significant structural heart disease. However, frequent ventricular ectopic beats can be extremely symptomatic and even incapacitating in some patients. Currently, reassurance and pharmacologic therapy are the mainstays of treatment. There has been little information on the use of catheter ablation in such patients. METHODS Ten patients with frequent and severely symptomatic monomorphic ventricular ectopic beats were selected from three tertiary care centers. The mean frequency +/- SD of ventricular ectopic activity was 1,065 +/- 631 beats/h (range 280 to 2,094) as documented by baseline 24-h ambulatory electrocardiographic (ECG) monitoring. No other spontaneous arrhythmias were documented. These patients had previously been unable to tolerate or had been unsuccessfully treated with a mean of 5 +/- 3 antiarrhythmic drugs. The site of origin of ventricular ectopic activity was accurately mapped by using earliest endocardial activation time during ectopic activity or pace mapping, or both. RESULTS During electrophysiologic study, no patient had inducible ventricular tachycardia. The ectopic focus was located in the right ventricular outflow tract in nine patients and in the left ventricular posteroseptal region in one patient. Frequent ventricular ectopic beats were successfully eliminated by catheter-delivered radiofrequency energy in all 10 patients. The mean number of radiofrequency applications was 2.6 +/- 1.3 (range 1 to 5). No complications were encountered. During a mean follow-up period of 10 +/- 4 months, no patient had a recurrence of symptomatic ectopic activity, and 24-h ambulatory ECG monitoring showed that the frequency of ventricular ectopic activity was 0 beat/h in seven patients, 1 beat/h in two patients and 2 beats/h in one patient. CONCLUSIONS Radiofrequency catheter ablation can be successfully used to eliminate monomorphic ventricular ectopic activity. It may therefore be a reasonable alternative for the treatment of severely symptomatic, drug-resistant monomorphic ventricular ectopic activity in patients without significant structural heart disease.

Predictors and Clinical Impact of Atrial Fibrillation After Pacemaker Implantation in Elderly Patients Treated with Dual Chamber Versus Ventricular Pacing

The Pacemaker Selection in the Elderly (PASE) trial was a prospective, multicenter, single blind, randomized comparison of single chamber, rate adaptive, ventricular pacing (VVIR) with dual chamber, rate adaptive pacing (DDDR) in 407 patients aged ≥65 years (mean 76 ± 7 years, 60% male) with standard bradycardia indications for dual chamber pacemaker implantation. The incidence, predictors, and clinical consequences of atrial fibrillation (AF) developing after pacemaker implantation in the PASE trial were studied prospectively. During a median follow‐up of 18 months, AF developed in 73 (18%) patients. Kaplan‐Meier estimated cumulative incidences of AF in patients with sinus node dysfunction (n = 176) at 18 months were 28% in the VVIR and 16% in the DDDR groups (P = 0.08). After adjustment for other clinical variables using a Cox multivariate regression model, randomization to VVIR compared with DDDR pacing mode among patients with sinus node dysfunction was independently associated with a 2.6‐fold increased relative risk (RR) of developing AF after pacemaker implantation (P = 0.01). Other independent clinical risk factors for development of postimplant AF included a preimplant history of hypertension (P = 0.02) or supraventricular tachyarrhythmias (P < 0.04). Patients who developed AF had similar health related quality of life scores and cardiovascular functional status after 18 months of pacing as patients who remained free of AF. The RR of death, stroke, or heart failure hospitalization was not increased in patients who developed AF. Thus, in the elderly patients with sinus node dysfunction requiring permanent pacing, DDDR pacing mode protected against the development of AF. However, development of AF after pacemaker implantation in this population was not associated with a significant impact on quality‐of‐life, functional status, or other clinical endpoints during 18 months of follow‐up. (PACE 2003; 26:2000–2007)

Percutaneous transluminal coronary angioplasty in octogenarians with unstable coronary syndromes

Abstract Coronary artery disease is a common and crippling condition in the elderly population. It is estimated that limitation of activity and compromised quality of life occurs in 85% of men and 55% of women in older age groups (>75 years) who have cardiovascular disease. 1 Little information has been reported regarding the outcome of percutaneous transluminal coronary angioplasty (PTCA) in octogenarians with unstable coronary syndromes. This is because older patients are usually excluded from randomized trials for interventional treatment, and today such treatment modalities are usually avoided unless they prolong longevity. This report documents our experience with PTCA in a group of elderly patients with unstable coronary syndromes. For this study, a special computerized data base was formulated from retrospective reviews of medical records, cineangiograms and patient interviews.

Clinical Experience with Passive-Fixation Coradial Bipolar Endocardial Pacing Leads

Bipolar, transvenous, passive‐fixation leads (ThinLine(tm) Sulzer Intermedics Inc., Angleton, TX, USA) incorporating coradial individually coated conductor coils, and a redundant external 55D polyurethane insulation sheath were developed. The diameter of the new leads (< 5 FT) is in the range of available unipolar leads and is considerably smaller than conventional bipolar pacing leads. From January 9, 1994 to November 12, 1996, 1,536 model 432–04 (523 atrial) and 430–10 (1,013 ventricular) leads were implanted in 1,068 patients at 50 US and 5 Canadian centers to evaluate their safety and efficacy. The study included a general phase, with follow‐ups at 1, 3, 6, 12, 18, and 24 months; and a randomized intensive phase with collection of more data and additional 2‐ and 6‐week follow‐ups. Capture and sensing thresholds, lead impedance, and handling characteristics were evaluated. Clinical events were monitored and performance was compared to that of two commercially available conventional (coaxial) leads: Sulzer Intermedics models 432–03 (atrial) and 430–07 (ventricular). During a total of 17,530 device months, there were two lead failures, no lead related deaths, 32 explants, 37 complications, and no unexpected adverse device effects. Capture thresholds were lower than those for coaxial controls with identical electrodes, sensing was comparable, lead impedances were within clinically acceptable ranges, and investigators found overall handling characteristics good to excellent. ThinLine coradial bipolar leads are safe and effective for cardiac pacing and sensing.

Effects of Internal Defibrillation on an Implanted Pacing System with Programmable Polarity

Management of multiple cardiac arrhythmias in some patients with both an implantable cardioverter defibrillator (ICD) and a pacemaker has demonstrated several advantages. In such circumstances, it is imperative that pacemaker function and its programmed parameters be preserved following a deftbrillation shock. This article describes the effects encountered by a specific programmable polarity pacemaker (Relay® 294–03) when subjected to electrical defibrillation in a canine model. Three pacemakers were repeatedly tested in three separate dog experiments. Each pacemaker, with its leads implanted in the right atrium and the right ventricle, was subjected to a minimum total number of 24 high energy biphasic and monophasic shocks (600–700 V) delivered by a coexisting ICD system using three different defibrillating lead configurations. None of the pacemaker systems showed any failure in function; all pacemakers continued to function within preshock specification and conversion to unipolar pacing and/ or backup mode was not observed in any of the tests. Intracardiac electrical potentials measured directly off the ICD and the pacemaker leads, during a defibrillation shock (mean 566.6 V; 23.7 J), showed that potentials measured in a bipolar configuration (tip‐ring: mean 21.0 V in atrium, 12.0 V in ventricle) were significantly less than potentials measured in a unipolar configuration (tip‐can: mean 387.9 V in atrium, 394.0 V in ventricle; ring‐can: mean 405.6 V in atrium, 395.4 V in ventricle). Our compatibility tests demonstrate that use of this programmable‐polarity pacemaker in concert with an ICD system appears to be safe. Testing similar to the present study should be conducted prior to complete clinical acceptance of combined ICD and pacemaker implantation.