Value of VDD-pacing systems in patients with atrioventricular block: experience over a decade.

BACKGROUND: Even though current guidelines suggest the use of VDD pacemakers in patients with AV block and normal sinus node function, a DDD system is often preferred for fear of either long-term atrial undersensing or late sinus node dysfunction and the resultant need for system upgrades. METHODS: We evaluated the long-term follow-up of all VDD pacemakers implanted in our center between 1992 and 2001 regarding atrial sensing, maintenance of AV synchrony, incidence of atrial fibrillation (AF), or the need for system upgrade, respectively. RESULTS: 320 consecutive patients (56% men, age 75+/-13 years) received a VDD pacemaker for the following indications: third-degree AV block 54%, second-degree AV block 34%, fascicular block with first-degree AV block and syncope 6%, others 6%. 138 patients (43%) died during follow-up, 3.8+/-2.3 years after implantation. Follow-up duration was 6.1+/-2.5 years in the remaining patients. At the last follow-up, 268 pacemakers (84%) were programmed to the VDD mode, 47 pacemakers (15%) were permanently programmed to the VVI mode (AF 36, undersensing 7, others 4, respectively). In five patients a DDD upgrade was necessary for sinus node dysfunction (3) or lead defect (2). Lead revision was performed in 19 patients (6%) (ventricular lead dislocation 7, atrial undersensing 6, lead fracture 3, others 2, respectively). CONCLUSION: VDD pacemakers have an excellent long-term performance in patients with AV block. They have a very low incidence of lead revisions for atrial undersensing (2%) and DDD upgrades for secondary sinus node dysfunction (1%).

Evidence for left ventricular remodeling after percutaneous coronary intervention: effect of percutaneous coronary intervention on left ventricular ejection fraction and volumes.

BACKGROUND: Post-stress ejection fraction (EF), end-diastolic (EDV) and end-systolic (ESV) volumes by gated myocardial perfusion SPECT (MPS) are well validated, reproducible and of prognostic significance. However, little is known about the impact of percutaneous coronary intervention (PCI) on left ventricular volumes and remodeling. METHODS: Thirty-eight patients who underwent MPS before and 6 months after PCI were evaluated. MPS were interpreted deriving summed stress (SSS), rest (SRS) and difference (SDS = SSS-SRS; extent of ischemia) scores. EF, EDV and ESV were generated by QGS trade mark. Pre-PCI MPS were compared to post-PCI MPS. RESULTS: Single vessel disease was present in 63% of patients. PCI of one vessel was performed in 82% of patients. After 6 months, SSS (10.6 +/- 6.3 vs. 2.8 +/- 4.3, p < 0.001) and SDS (8.2 +/- 5.6 vs. 1.4 +/- 2.3, p < 0.001) had improved; however, EF did not change significantly (55 +/- 10 vs. 57 +/- 13, p = ns). Still, EDV (105 +/- 25 ml vs. 96 +/- 25 ml, p = 0.006) and ESV (49 +/- 19 ml vs. 41 +/- 18 ml, p = 0.001) were significantly reduced. CONCLUSION: Results of MPS documented the beneficial effect of PCI on symptoms and extent of ischemia. In addition, the findings showed a significant decrease in ESV and EDV after PCI as compared to pre-PCI findings which points to a positive effect on left ventricular remodeling even in the absence of significant changes in EF.

Long-term outcome of patients with silent versus symptomatic ischemia six months after percutaneous coronary intervention and stenting.

OBJECTIVES: We sought to evaluate the incidence of silent ischemia versus symptomatic ischemia six months after percutaneous coronary intervention (PCI) and its impact on prognosis and to test the utility of myocardial perfusion single-photon emission computed tomography (SPECT), or MPS, for risk stratification in these patients. BACKGROUND: Silent ischemia is frequent after PCI. However, little is known about silent ischemia and long-term outcome after PCI and stenting. METHODS: In 356 consecutive patients with successful PCI and stenting and follow-up MPS after six months, long-term follow-up (4.1 +/- 0.3 years) was performed. The MPS images were interpreted by defining summed stress, rest, and difference scores (summed difference score [SDS] = extent of ischemia) and related to symptoms and outcome. Critical events included cardiac death, myocardial infarction, and target vessel revascularization. RESULTS: Eighty-one patients (23%) had evidence of target vessel ischemia, which was silent in 62%. The only independent predictor of silent ischemia was SDS (odds ratio 0.64, p = 0.001). During follow-up, 67 critical events occurred. For patients with an SDS of 0, 1-4, and >4, the critical event rates were 17%, 29%, and 69%, respectively. Similarly, patients without ischemia, silent ischemia, and symptomatic ischemia had 17%, 32%, and 52% of critical events, respectively. Diabetes (relative risk 1.98, p = 0.03) and SDS (relative risk 1.2, p < 0.001) were independent predictors of critical events. The MPS image added incremental information for the prediction of critical events. CONCLUSIONS: Six months after PCI and stenting, 23% of patients had target vessel ischemia, which was silent in 62%. Silent ischemia predicted a worse outcome than did no ischemia and tended to have a better outcome than symptomatic ischemia. This was closely related to the extent of ischemia. The SDS added incremental value to pre-scan findings with respect to diagnosis and prognosis, indicating the utility of MPS for risk stratification after PCI and stenting.