Prognosis of pacing-dependent patients with cardiovascular implantable electronic devices.

BACKGROUND: Data on the prognostic significance of pacing dependency in patients with cardiovascular implantable electronic devices (CIEDs) are sparse. METHODS: The prognostic significance of pacing dependency defined as absence of an intrinsic rhythm ≥ 30 bpm was determined in 786 patients with CIEDs at the authors' institution using univariate and multivariate regression analysis to identify predictors of all-cause mortality. RESULTS: During 49 months median follow-up, death occurred in 63 of 130 patients with pacing dependency compared to 241 of 656 patients without pacing dependency (48% versus 37%, hazard ratio [HR] 1.34; 95% confidence interval [CI]: 1.02-1.78, P = 0.04). Using multivariate regression analysis, predictors of all-cause mortality included age (HR 1.07; 95% CI: 1.05-1.08, P < 0.01), history of atrial fibrillation (HR 1.32, 95% CI: 1.03-1.69, P < 0.01), chronic kidney disease (HR 1.28; 95% CI: 1.00-1.63, P = 0.048) and New York Heart Association (NYHA) class ≥ III (HR 2.00; 95% CI: 1.52-2.62, P < 0.01), but not pacing dependency (HR 1.15; 95% CI: 0.86-1.54, P = 0.35). CONCLUSIONS: In contrast to age, atrial fibrillation, chronic kidney disease and heart failure severity as indexed by NYHA functional class III or IV, pacing dependency does not appear to be an independent predictor of all-cause mortality in patients with CIEDs.

Predictors of pacing-dependency in patients with cardiovascular implantable electronic devices.

BACKGROUND: Data on the prevalence and predictors for the development of pacing-dependency in patients with cardiovascular implantable electronic devices (CIEDs) are sparse. METHODS: Pacing-dependency defined as an absence of intrinsic rhythm of ≥ 30 bpm was determined in 802 consecutive patients with CIEDs who visited the documented pacemaker or implantable cardioverter- defibrillator outpatient clinic for routine follow-up. RESULTS: A total of 131 (16%) patients were found to be pacing-dependent 67 ± 70 months after CIED implant. Multivariate analysis revealed a significant association between pacing-dependency and the following clinical variables: second or third-degree atrioventricular (AV) block at implant (OR = 19.9; 95% CI: 10.9-38.5, p < 0.01), atrial fibrillation at implant (OR = 2.15; 95% CI: 1.16-4.05, p = 0.02), left ventricular ejection fraction (LVEF) ≤ 30% (OR = 2.06; 95% CI: 1.03-4.15, p = 0.04), B-type natriuretic peptide (BNP) > 150 pg/mL (OR = 2.12; 95% CI: 1.16-3.97, p = 0.02), chronic kidney disease (OR = 1.86; 95% CI: 1.08-3.26, p = 0.03), and follow-up duration after implantation > 5 years (OR = 3.29; 95% CI: 1.96-5.64, p < 0.01). None of the remaining clinical variables including age, gender, diabetes mellitus, underlying heart disease, prior cardiac surgery or medication during follow-up including betablockers and amiodarone predicted pacing-dependency. CONCLUSIONS: Pacing-dependency is associated with second or third-degree AV-block at implant, atrial fibrillation before implant, low LVEF, elevated BNP, chronic kidney disease and follow-up duration after implant.

Structural, Pro-Inflammatory and Calcium Handling Remodeling Underlies Spontaneous Onset of Paroxysmal Atrial Fibrillation in JDP2-Overexpressing Mice.

BACKGROUND: Cardiac-specific JDP2 overexpression provokes ventricular dysfunction and atrial dilatation in mice. We performed in vivo studies on JDP2-overexpressing mice to investigate the impact of JDP2 on the predisposition to spontaneous atrial fibrillation (AF). METHODS: JDP2-overexpression was started by withdrawal of a doxycycline diet in 4-week-old mice. The spontaneous onset of AF was documented by ECG within 4 to 5 weeks of JDP2 overexpression. Gene expression was analyzed by real-time RT-PCR and Western blots. RESULTS: In atrial tissue of JDP2 mice, besides the 3.6-fold increase of JDP2 mRNA, no changes could be detected within one week of JDP2 overexpression. Atrial dilatation and hypertrophy, combined with elongated cardiomyocytes and fibrosis, became evident after 5 weeks of JDP2 overexpression. Electrocardiogram (ECG) recordings revealed prolonged PQ-intervals and broadened P-waves and QRS-complexes, as well as AV-blocks and paroxysmal AF. Furthermore, reductions were found in the atrial mRNA and protein level of the calcium-handling proteins NCX, Cav1.2 and RyR2, as well as of connexin40 mRNA. mRNA of the hypertrophic marker gene ANP, pro-inflammatory MCP1, as well as markers of immune cell infiltration (CD68, CD20) were increased in JDP2 mice. CONCLUSION: JDP2 is an important regulator of atrial calcium and immune homeostasis and is involved in the development of atrial conduction defects and arrhythmogenic substrates preceding paroxysmal AF.

[Cardiac memory following pacemaker implantation]. / Cardiac Memory nach Schrittmacherimplantation.

BACKGROUND: Although T wave inversions due to cardiac memory were described already 50 years ago, little is known about the prevalence and about clinical predictors of this phenomenon. METHODS: After exclusion of 238 patients due to bundle branch block or pacemaker dependency, a total of 325 consecutive patients were enrolled in this study during routine outpatient control of their pacemaker. A 12-lead standard ECG was obtained in all patients during transient inhibition of pacing therapy. RESULTS: Cardiac memory could be documented in 115 of 325 patients (35%) and showed a strong association with the amount of ventricular stimulation. The prevalence of cardiac memory was 9% in patients with ≤25% ventricular stimulation and 86% in patients with ≥75% ventricular stimulation. DISCUSSION: Cardiac memory was observed in one third of patients following pacemaker implantation. The prevalence of cardiac memory in the ECG with intrinsic rhythm is above 80% in patients with frequent ventricular stimulation. Cardiac memory due to ventricular stimulation is benign and should not be confused with similar T wave inversions due to acute coronary syndrome, severe left ventricular hypertrophy, or myocarditis.

Cheyne-stokes respiration during wakefulness in patients with chronic heart failure.

PURPOSE: Cheyne-Stokes respiration (CSR) during sleep has been studied extensively in patients with chronic heart failure (CHF). Prevalence and prognostic significance of CSR during wakefulness in CHF, however, are largely unknown. METHODS: CSR during wakefulness with an apnea-hypopnea cut-off ≥5/h and moderate to severe CSR with an apnea-hypopnea cutoff ≥15/h were analyzed using polysomnographic recordings in 267 patients with stable CHF with reduced left ventricular (LV) ejection fraction at our institution. Primary endpoint during follow-up was heart transplant-free survival. RESULTS: Fifty of 267 patients (19%) had CSR during wakefulness and 73 of 267 patients (27%) had CSR during sleep. CSR during wakefulness was associated with advanced age, atrial fibrillation, decreased LV ejection fraction, increased LV end-diastolic diameter, brain natriuretic peptide, New York Heart Failure class, and CSR during sleep. During 43 months mean follow-up, 67 patients (25%) died and 4 patients (1%) underwent heart transplantation. Multivariate Cox analysis identified age, male gender, chronic kidney disease, and LV ejection fraction as predictors of reduced transplant-free survival. CSR during wakefulness with an apnea-hypopnea cutoff ≥5/h as well as moderate to severe CSR while awake using an apnea-hypopnea cutoff ≥15/h did not predict reduced transplant-free survival independently from confounding factors. CONCLUSION: CSR during wakefulness appears to be a marker of heart failure severity.

[Multiple inappropriate defibrillator shocks due to insulation failure of a Biotronik Linox defibrillator lead with externalized conductor]. / Multiple inadäquate Defibrillatorschocks bei Isolationsdefekt einer Biotronik-Linox®-Defibrillatorelektrode mit externalisiertem Leiter.

In this article the case of a patient who received a total of 35 inappropriate defibrillator shocks due to insulation failure with externalized conductor of a Biotronik Linox® lead is described. The implanted defibrillator was immediately inactivated and the failed lead was extracted using a laser sheath system.

Prognostic impact of central sleep apnea in patients with heart failure.

BACKGROUND: Central sleep apnea (CSA) is common in patients with heart failure (HF). Earlier studies investigating the influence of CSA on mortality in HF patients, however, have yielded contradictory results. METHODS AND RESULTS: In a prospective study involving 267 patients with left ventricular (LV) ejection fractions ≤50%, we performed polysomnography and compared heart transplant-free survival rates between patients with no or mild CSA (apnea-hypopnea index [AHI] ≤15/h) and those with moderate CSA (AHI 15.1-30/h) or severe CSA (AHI >30/h). During 43 ± 18 months' mean follow-up, 67 patients (25%) died and 4 patients (1%) underwent heart transplantation. Multivariate Cox analysis identified age, male sex, chronic kidney disease, and decreased LV ejection fraction, but not moderate CSA or severe CSA, as predictors of transplant-free survival. CONCLUSIONS: In patients with stable HF, moderate CSA as well as severe CSA do not appear to predict transplant-free survival independently from confounding factors.

Severe central sleep apnea is associated with atrial fibrillation in patients with left ventricular systolic dysfunction.

BACKGROUND: The results of previous studies investigating the association between atrial fibrillation (AF) and central sleep apnea (CSA) in patients with left ventricular (LV) systolic dysfunction are contradictory. METHODS: We prospectively enrolled 267 patients in this cross-sectional study with LV ejection fractions ≤50%, who were screened for sleep disordered breathing using cardiorespiratory polysomnography after patients with predominantly obstructive sleep apnea or insufficient sleep studies had been excluded. RESULTS: AF at study entry was found in 70 of 267 patients (26%). CSA with an apnea/hypopnea index (AHI) ≥15/hour was present in 116 patients (43%) and 67 patients (25%) had severe CSA with an AHI > 30/hour. Univariate analysis revealed a significant association between AF and severe CSA, age, male gender, arterial hypertension, left atrial diameter, brain natriuretic peptide, chronic kidney disease, New York Heart Association class, digitalis, and the lack of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Multivariate analysis revealed a significant association between AF and severe CSA (odds ratio [OR]: 5.21; 95% confidence interval [CI]: 1.67-16.27, P = 0.01), age (OR: 1.22 per 5-year increase; 95% CI: 1.05-1.40, P = 0.01), left atrial diameter (OR 1.61 per 5-mm increase; 95% CI: 1.22-2.01, P < 0.01), and digitalis (OR: 2.7; 95% CI: 1.26-5.79, P = 0.01). CONCLUSIONS: AF is associated with severe CSA but not with moderate CSA in addition to age, use of digitalis, and left atrial size in patients with LV systolic dysfunction. Future studies evaluating the potential benefit of adaptive servo-ventilation therapy to prevent AF or to decrease the AF burden in heart failure patients should therefore focus on patients with severe central sleep apnea.

Cardiac arrhythmias and sleep-disordered breathing in patients with heart failure.

The relationship between heart failure (HF), sleep-disordered breathing and cardiac arrhythmias is complex and poorly understood. Whereas the frequency of predominantly obstructive sleep apnea in HF patients is low and similar or moderately higher to that observed in the general population, central sleep apnea (CSA) has been observed in approximately 50% of HF patients, depending on the methods used to detect CSA and patient selection. Despite this high prevalence, it is still unclear whether CSA is merely a marker or an independent risk factor for an adverse prognosis in HF patients and whether CSA is associated with an increased risk for supraventricular as well as ventricular arrhythmias in HF patients. The current review focuses on the relationship between CSA and atrial fibrillation as the most common atrial arrhythmia in HF patients, and on the relationship between CSA and ventricular tachycardia and ventricular fibrillation as the most frequent cause of sudden cardiac death in HF patients.

Daytime sleepiness in patients with obstructive sleep apnea and severe obesity: prevalence, predictors, and therapy.

BACKGROUND: We sought to determine prevalence and predictors of excessive daytime sleepiness in patients with severe obesity with a body mass index (BMI) > 35 kg/m(2) and obstructive sleep apnea (OSA) with an apnea-hypopnea index > 15/h. METHODS: The study population consisted of 245 obese OSA patients with a BMI > 35 kg/m(2), who were retrospectively recruited from 3256 consecutive patients who underwent polysomnography at our sleep laboratory between 2006 and 2009. Baseline clinical characteristics and polysomnography results of these 245 patients were compared between patients with and without excessive daytime sleepiness, which was diagnosed in the presence of an Epworth Sleepiness Scale score (ESS) ≥ 11. RESULTS: A total of 123 of 245 study patients (50.2 %) had an ESS ≥ 11. Patients with an ESS ≥ 11 were younger and less often unemployed or retired compared with patients with an ESS < 11. Polysomnography revealed a longer total sleep time (TST), higher sleep efficiency, and shorter sleep latency in patients with ESS ≥ 11. In addition, obstructive apneas during TST as well as oxygen saturations < 80 % occurred significantly more often in patients with versus without an ESS ≥ 11. Improvement of daytime sleepiness after initiation of continuous positive airway pressure (CPAP) therapy occurred more often in patients with versus without ESS ≥ 11 (93 versus 73 %, p < 0.01). CONCLUSION: Obese patients with OSA and excessive daytime sleepiness are characterized by younger age, longer TSTs, more frequent obstructive apneas, and oxygen desaturations < 80 % compared with patients without excessive daytime sleepiness. Excessive daytime sleepiness can be improved in more than 90 % of patients using CPAP therapy.

[Laser sheath extraction of an infected pacemaker lead]. / Extraktion einer infizierten Schrittmacherelektrode mittels Lasersheath.

A case of pacemaker electrode infection with Staphylococcus aureus is presented. In order to avoid sternotomy, the right ventricular pacemaker lead, which had been implanted for 15 years, was successfully extracted using a laser sheath despite large endocarditic vegetations on the pacemaker lead. After completion of a 6-week course of antibiotics, the patient was discharged without any further evidence of infection.

Left ventricular function improvement after prophylactic implantable cardioverter-defibrillator implantation in patients with non-ischaemic dilated cardiomyopathy.

AIMS: To assess the incidence and prognostic significance of left ventricular (LV) function improvement in patients with non-ischaemic dilated cardiomyopathy (DCM) and prophylactic implantable cardioverter-defibrillator (ICD). METHODS AND RESULTS: A total of 123 patients with DCM and echocardiographic follow-up assessments within 1 year after prophylactic ICD implant were retrospectively studied at our institution. All patients had New York Heart Association class II or III symptoms in the presence of a LV ejection fraction of 23 ± 6% (range: 9-35%) despite optimized medical therapy for at least 3 months prior to ICD implant. Left ventricular function improvement was defined as an increase of LV ejection fraction of more than 5% to more than 35% combined with a decrease LV end-diastolic diameter of at least 5 mm. Left ventricular function improvement after prophylactic ICD implant was found in 30 of 123 patients (24%). Multivariate logistic regression revealed recent onset DCM with symptoms ≤9 months as the only significant predictor of LV function improvement [odds ratio: 6.89; 95% confidence interval (CI): 2.43-21.99, P = 0.0002]. During 74 months mean follow-up, total mortality was higher in patients without vs. with LV function improvement [hazard ratio (HR): 3.75; 95% CI: 1.14-12.31, P = 0.0034], while the incidence of appropriate ICD therapies was similar in both groups in the early phase after prophylactic ICD implant (HR: 1.15; 95% CI: 0.57-2.33, P = 0.70). The incidence of appropriate ICD therapies decreased to ∼1% per year after LV function improvement had occurred. CONCLUSION: Recently diagnosed DCM predicts LV function improvement after prophylactic ICD implant. Overall survival was significantly better in patients with vs. without LV function improvement, while appropriate ICD therapy rates were similar in both groups in the early phase after prophylactic ICD implantation before LV function improvement occurred.

Sleep-disordered breathing in patients with implantable cardioverter-defibrillator.

AIMS: To assess the prognostic significance of screening for sleep-disordered breathing in patients with implantable cardioverter-defibrillator (ICD) with regard to appropriate ICD therapy and total mortality. METHODS AND RESULTS: Overnight sleep studies were performed in 204 ICD recipients not known to have sleep apnoea and with no history of daytime sleepiness. Sleep-disordered breathing was diagnosed in the presence of an apnoea-hypopnea index of five or more events per hour. Seventy patients (34%) had no sleep apnoea, 105 patients (51%) had central sleep apnoea, and 29 patients (14%) had obstructive sleep apnoea. During 38 ± 26 months follow-up, 80 patients (39%) received appropriate ICD therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF), and 54 patients (26%) died. On multivariate Cox regression analysis, age, left ventricular (LV) end-diastolic diameter, secondary prevention ICD indication, use of diuretics, and absence of aldosterone antagonist therapy but not sleep apnoea were associated with appropriate ICD therapy for VT or VF. In addition, multivariate Cox analysis identified age and LV ejection fraction but not sleep apnoea as predictors of total mortality. CONCLUSION: Undiagnosed sleep-disordered breathing is common in ICD recipients. The presence and severity of previously unknown sleep apnoea in ICD recipients, however, does not appear to be an independent predictor of appropriate ICD therapy or morality during follow-up.

[Sleep disordered breathing and nonsustained ventricular tachycardia in patients with chronic heart failure]. / Schlafbezogene Atmungsstörungen und maligne ventrikuläre Arrhythmien bei Patienten mit chronischer Herzinsuffizienz.

BACKGROUND: Patients with chronic heart failure (CHF) have a high incidence of sleep disordered breathing (SDB). It is assumed that patients with the combination of CHF and SDB have more ventricular couplets and nonsustained ventricular tachycardia (NSVT) than patients without SDB. METHODS: In 63 patients, 49 men and 14 women with chronic heart failure (EF < 45%), all-night polysomnography and long-term-ECG were performed. Mean age was 59 ± 15 years, mean BMI 27 ± 5 kg/m(2). 56% had an ischemic, 44% a nonischemic heart disease. 51% had heart insufficiency classification NYHA III. RESULTS: 42 of the 63 patients (67%) had sleep disordered breathing (SDB) with an AHI ≥5/h. In 24 patients (38%) SDB was central, in 18 (29%) obstructive. More patients with SDB than patients without SDB had NSVT (50% vs. 19%). Nocturnal frequency of NSVT in patients with SDB was about twice as high as the rate observed during daytime (0.48/h vs. 0.21/h). In patients without SDB there was no relevant difference between day and night (0.23/h vs. 0.21/h). AHI correlated with NSVT (r = 0.329, p < 0.01). Day/night comparison of couplets was 2.3/h vs. 1.9/h in SDB patients and 2.0/h vs. 1.6/h in patients without SDB. CONCLUSIONS: Patients with chronic heart failure have a high prevalence of SDB. The combination of CHF and SDB predisposes for nocturnal malignant ventricular arrhythmias.

Sleep-disordered breathing in recipients of implantable defibrillators.

STUDY OBJECTIVES: To examine the prevalence and clinical significance of sleep-disordered breathing in patients with implantable cardioverter defibrillators (ICD). METHODS AND RESULTS: Overnight sleep studies were performed in 129 ICD recipients who had no history of sleep apnea. The mean left ventricular ejection fraction (LVEF) was 29 +/- 11%. Mild, moderate, and severe sleep apnea was diagnosed in the presence of an apnea/hypopnea index (AHI) of 5-15/h, 15.1-30/h, and >30/h, respectively. No sleep apnea was present in 49 patients (38%), 57 (44%) had central sleep apnea (CSA), and 23 patients (18%) had obstructive sleep apnea (OSA). Mild, moderate, and severe sleep apnea were present in 25%, 31%, and 44% of patients with CSA, compared with 52%, 22%, and 26% of patients with OSA (P < 0.05). LVEF was similar in patients with versus without OSA or CSA. Patients with CSA were significantly older and had a higher prevalence of ischemic cardiomyopathy than patients without sleep apnea. CONCLUSIONS: Previously undiagnosed CSA is common in ICD recipients. Severely disordered breathing during sleep was more prevalent among patients with CSA than patients with OSA. This prospective, observational study will examine the long-term clinical significance of sleep-disordered breathing in ICD recipients.