| 1. |
- Gottfridsson, Christer, 1958, et al.
(författare)
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Acute evaluation of transthoracic impedance vectors using ICD leads.
- 2009
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Ingår i: Pacing and clinical electrophysiology : PACE. - : Wiley. - 1540-8159 .- 0147-8389. ; 32:6, s. 762-71
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Minute ventilation (MV) has been proven to be very useful in rate responsive pacing. The aim of this study was to evaluate the feasibility of using implantable cardioverter-defibrillator (ICD) leads as part of the MV detection system. METHODS: At implant in 10 patients, the transthoracic impedance was measured from tripolar ICD, tetrapolar ICD, and atrial lead vectors during normal, deep, and shallow voluntary respiration. MV and respiration rate (RespR) were simultaneously measured through a facemask with a pneumotachometer (Korr), and the correlations with impedance-based measurements were calculated. Air sensitivity was the change in impedance per change in respiratory tidal volume, ohms (Omega)/liter (L), and the signal-to-noise ratio (SNR) was the ratio of the respiratory and cardiac contraction components. RESULTS: The air sensitivity and SNR in tripolar ICD vector were 2.70 +/- 2.73 ohm/L and 2.19 +/- 1.31, respectively, and were not different from tetrapolar. The difference in RespR between tripolar ICD and Korr was 0.2 +/- 1.91 breaths/minute. The regressed correlation coefficient between impedance MV and Korr MV was 0.86 +/- 0.07 in tripolar ICD. CONCLUSIONS: The air sensitivity and SNR in tripolar and tetrapolar ICD lead vectors did not differ significantly and were in the range of the values in pacemaker leads currently used as MV sensors. The good correlations between impedance-based and Korr-based RespR and MV measurements imply that ICD leads may be used in MV sensor systems.
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| 2. |
- Gottfridsson, Christer, 1958, et al.
(författare)
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Sex difference and factors associated with outcome in patients with sustained ventricular arrhythmias.
- 2008
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Ingår i: Scandinavian cardiovascular journal : SCJ. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 42:3, s. 182-91
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To describe gender differences and factors of importance for outcome in patients referred for sustained ventricular arrhythmias. RESULTS: Two hundred and fifty three patients took part in the survey, 126 (20 women) had sustained monomorphic ventricular tachycardia (VT) and 127 (31 women) had polymorphic VT/ventricular fibrillation. Ischemic heart disease was less common in women than in men (47 vs. 80%). At discharge, an ICD implant was similarly common in women (33%) and men (29%). One hundred and twenty five (65%) men and 37 (79%) women were alive at follow-up, p =0.08 (median follow-up 53 months). Independent predictors of long-term mortality were: 1) PVT/VF as the presenting arrhythmia, 2) a low ejection fraction, 3) increased QRS duration and 4) diabetes mellitus. CONCLUSION: The lower proportion of women compared to men being referred for evaluation of sustained ventricular arrhythmias may contribute to the lower number of ICD implants in women. The long-term survival in women and men did not differ significantly.
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| 3. |
- Sandstedt, Bengt, 1951, et al.
(författare)
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Testing the implantable cardioverter-defibrillator after implantation--is it necessary?
- 2007
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Ingår i: Pacing Clin Electrophysiol. - 0147-8389. ; 30:8, s. 985-91
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Tidskriftsartikel (refereegranskat)abstract
- The results of intraoperative and postoperative predischarge implantable cardioverter-defibrillator (ICD) testing of 211 consecutive patients, starting at 15 J and requiring two successful terminations of induced VT/VF with a relative defibrillation safety margin (DSM) of >10 J, were reviewed. The aim was to define the type of intraoperative response that would make postoperative predischarge testing unnecessary. The intraoperative responses were divided into three types: A, a DSM > or =10 J and an absolute energy level of < or =20 J; B, a DSM of > or =10 J and an absolute energy level of >20 J; and C, a DSM <10 J and an absolute energy level of >20 J. At operation, the responses to defibrillation were A, 88.6%; B, 7.1%; and C, 4.3%. Accepting an A response only would leave 11.4% of the patients for postoperative testing. The positive and negative predictive values for diagnosing a postoperative C response were 0.78 and 0.97, respectively. Similarly, the predictive values for diagnosing a postoperative B or C response were 0.71 and 0.97, respectively. The postoperative testing responses were A, 89.1%; B, 4.3%; and C, 6.6%. In summary, an intraoperative A response was sufficient to make a postoperative defibrillation testing unnecessary, while it was found that intraoperative B and C responders should undergo postoperative testing. Applying these criteria, approximately 90% of the patients could be discharged without any postoperative induction test.
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