To our knowledge, this study presents the first method for quantitative assessment of recruitable collateral blood flow in humans in the catheterization laboratory. Sufficient and insufficient collateral circulation can be reliably distinguished by this method. Use of this method can also help to provide more insight into the extent and behavior of the collateral circulation for investigational purposes and may have potential clinical implications.

The aim of this study was to determine the effect of patient and lead characteristics on occlusion of the access vein in pacemaker and ICD patients. Contrast venography of the access vein was obtained in 89 patients (17 patients with an ICD) scheduled for lead extraction. The indication for extraction was infection in 57 patients (systemic infection in 9) and lead malfunction in 32 patients. In 6 of the 89 patients, leads were introduced in both the right and left subpectoral area, resulting in a total of 95 venous entry sites. In 22 of these entry sites one lead was present, in 61 two leads, in 11 three, and in 1 four leads. The vessel patency was graded open or occluded. Occlusion of the subclavian vein occurred in four (13%) patients with lead malfunction versus 18 (32%) patients with infection (P = 0.07). In patients with systemic infection, 5 of 9 showed venous occlusion (P = 0.01 when compared to patients with malfunction, odds ratio 8.75, 95% confidence interval 1.21-64.11). Considered per entry site, the incidence of occlusion was 7 of 22 with one lead present, 17 of 61 with two leads, 0 of 11 with three leads, and 0 of 1 with four leads (P = 0.13). No patient had a superior vena caval occlusion. Patients with systemic infection have an increased risk of occlusion of the access vein. On the contrary, the study found no support for the concept that the risk of venous occlusion increases with a higher number of leads present.

By current guidelines a considerable part of the patients selected for cardiac resynchronization therapy (CRT) do not respond to the therapy. We hypothesized that mechanical discoordination [opposite strain within the left ventricular (LV) wall] predicts reversal of LV remodeling upon CRT better than mechanical dyssynchrony. MRI tagging images were acquired in CRT candidates (n = 19) and in healthy control subjects (n = 9). Circumferential strain (epsilon(cc)) was determined in 160 regions. From epsilon(cc) signals we derived 1) an index of mechanical discoordination [internal stretch fraction (ISF), defined as the ratio of stretch to shortening during ejection] and 2) indexes of mechanical dyssynchrony: the 10-90% width of time to onset of shortening, time to peak shortening, and end-systolic strain. LV end-diastolic volume (LVEDV), end-systolic volume (LVESV), and ejection fraction (LVEF) were determined before and after 3 mo of CRT. Responders were defined as those patients in whom LVESV decreased by >15%. In responders (n = 10), CRT increased LVEF and decreased LVEDV and LVESV (11 +/- 6%, 21 +/- 16%, and 30 +/- 16%, respectively) significantly more (P < 0.05) than in nonresponders (1 +/- 6%, 3 +/- 4%, and 5 +/- 10%, respectively). Among mechanical indexes, only ISF was different between responders and nonresponders (0.53 +/- 0.25 vs. 0.31 +/- 0.16; P < 0.05). In patients with ISF >0.4 (n = 10), LVESV decreased by 31 +/- 18% vs. 5 +/- 11% in patients with ISF <0.4 (P < 0.05). We conclude that mechanical discoordination, as estimated from ISF, is a better predictor of reverse remodeling after CRT than differences in time to onset and time to peak shortening. Therefore, discoordination rather than dyssynchrony appears to reflect the reserve contractile capacity that can be recruited by CRT.

Effective tools for extraction of pacemaker and ICD leads have been developed in the past decennium. This study investigated the necessity of using these tools in addition to direct traction in relation to patient and lead characteristics. The study encompasses first attempts at extraction of consecutive pacemaker and ICD leads from the subpectoral area. A stepwise extraction protocol was used with traction first (directly or with a locking stylet) followed by laser sheath extraction if not successful. The indication, patient age, time from implant, fixation mechanism, location, and insertion site of the leads were studied in relation to the outcome of traction. A total of 145 leads in 83 patients were extracted. Leads were implanted for 71 +/- 61 months. Indication for extraction was infection in 96 leads and malfunction in 49 leads. There were 90 ventricular leads including 16 ICD leads. Forty-nine (34%) leads were extracted with traction; in 96 (66%) leads a laser sheath was necessary. All leads implanted for < 6 months could be removed with traction alone. In a multivariate logistic regression model, time from implant was the main factor determining success of traction (P < 0.001), but in case of infection the success rate increased (P = 0.004). In conclusion, time from implant is the decisive factor to judge the potential efficacy of lead extraction with direct traction. If leads are implanted for 6 months, the availability of additional extraction tools is necessary when lead extraction is considered. In addition to time from implant, infected leads have a better chance to be removed with traction although it is a much weaker predictor.

Chronically implanted ventricular pacing and defibrillator (ICD) leads can adhere to the tricuspid valve. This study examined the effect of lead extraction, and laser sheath extraction in particular, on tricuspid valve regurgitation. Lead extraction was first tried with traction using limited force followed by a laser sheath if not successful. Tricuspid valve regurgitation before and after extraction was evaluated with transesophageal echocardiography and graded from 0 (none) to 4 (severe). A change in regurgitation was considered clinically relevant if it increased with two grades or more and resulted in at least grade 3 regurgitation. Fifty ventricular leads were extracted in 43 consecutive patients, including 14 ICD leads. In 20 patients (group I) leads were removed without a (laser) sheath crossing the tricuspid valve, in 23 patients (group II) leads were extracted with lasing across the valve. The mean time from implant was 43 +/- 43 months and 99 +/- 78 months, respectively, (P = 0.007). Tricuspid regurgitation increased in five (12%) patients. In group I only in one patient the laser failed proximal of the valve and forceful traction was subsequently used, and in group II this occurred in four (17%) patients. This difference did not reach statistical significance even excluding the patient from group I (P = 0.111). The increase of tricuspid regurgitation cautions against indiscriminate extraction of superfluous leads. There is a trend that when tools like a laser sheath are necessary the chance of tricuspid valve damage increases.

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In this study LV dyssynchrony remains the most important determinant of response to CRT, even in the presence of posterolateral scar provided atrioventricular and interventricular pacing intervals are optimized.

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