Incidence of ventricular arrhythmic events in CKD patients with ICD

Atrial Fibrillation and Ventricular Tachyarrhythmias: Advancements for Better Outcomes

Cardiac arrhythmias are associated with several cardiac diseases and are prevalent in people with or without structural and valvular abnormalities. Ventricular arrhythmias (VA) can be life threating and their onset require immediate medical attention. Similarly, atrial fibrillation and flutter lead to stroke, heart failure and even death. Optimal treatment of VA is variable and depends on the medical condition associated with the rhythm disorder (which includes reversible causes such as myocardial ischemia or pro-arrhythmic drugs). While an implanted cardioverter defibrillator is often indicated in secondary prevention of VA. This review highlights the newest advancements in these techniques and management of ventricular and atrial tachyarrhythmias, along with pharmacological therapy.

Implantable Cardioverter Defibrillators and Chronic Kidney Disease

Use of implantable cardioverter defibrillators (ICDs) is the treatment of choice for heart failure patients with ejection fraction <35% to prevent sudden cardiac death. Whether this benefit remains among patients with chronic kidney disease (CKD) or end stage renal disease (ESRD) is yet to be elucidated. We conducted a systematic review of studies in PubMed that have investigated the use of ICDs among patients with CKD or ESRD. From the 470 studies identified, we selected 42 for the current review. Patients with CKD/ESRD were more likely to get antitachycardia pacing or shocks and had higher cardiac and/or all-cause mortality compared to patients without CKD/ESRD. These associations had an inverse dose-response effect with worse outcomes with decreasing kidney function. In conclusion, use of ICDs in CKD/ESRD is associated with increased antitachycardia pacing/shocks and mortality suggesting that their routine use in this patient population may be associated with more adverse outcomes than benefits.

Arrhythmic episodes in patients implanted with a cardioverter-defibrillator - results from the Prospective Study on Predictive Quality with Preferencing PainFree ATP therapies (4P)

Background

Little is known about the ICD performance using enhanced detection algorithms in unselected, non-trial patients. Performance of recent generation ICD equipped with SmartShock™ technology (SST) for detection and conversion of ventricular tachyarrhythmias (VTA) was investigated.

Methods

4P was a prospective, multicenter, observational study conducted in 10 Swiss implanting centers. Patients with a Class I indication according to international guidelines were included and received an ICD with SST. ICD discrimination capability was assessed by evaluating SST performance; therapy efficacy was assessed by rate of VTA conversions by ATP and by rescue shocks.

Results

Overall, 196 patients were included in the analysis with a mean duration of follow-up of 27.7 months (452 patient-years of observation). Patient-specific rather than recommended programming was preferred. Device-detected episodes were frequent (5147 episodes in 146 patients, 74.5%). In 44 patients (22.4%), 1274 episodes were categorized as VTA; only 215 episodes were symptomatic. ATP was the first-line therapy and highly effective (99.9% success rate at the episode level, 100.0% at the patient level). Rescue shocks were rare (66 episodes in 28 patients); 7 shocks in 5 patients (2.6%) were inappropriate. Death and hospitalization rates were low.

Conclusions

In a cohort of non-trial, unselected ICD patients, VTA episodes were frequent. The 4P results confirm the robustness of VTA detection by SST and the effectiveness of ATP treatment, hence limiting overall ICD shock burden.

Assessment of Atrial Fibrillation and Ventricular Arrhythmia Risk After Transplant in Patients With End-Stage Renal Disease by P-wave/QT Interval Dispersion, T-Wave Peak-End Interval, and T-Wave Peak-End/QT Interval Ratio

OBJECTIVES

The association between end-stage renal disease with atrial fibrillation and ventricular arrhythmias is well documented. The aim of this study was to investigate whether kidney transplant has any effect on P-wave dispersion, a predictor of atrial fibrillation and corrected QT interval dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio, which are predictors of ventricular arrhythmias in patients with end-stage renal disease.

MATERIALS AND METHODS

In a retrospective study, 234 patients (125 kidney transplant and 109 healthy control patients) were examined. P-wave dispersion, corrected QT dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio values before and 3, 6, and 12 months after transplant were calculated and compared in transplant recipients. Baseline values of the control group were compared with 12-month values of kidney transplant patients.

RESULTS

We observed a statistically significant decline in P-wave dispersion, corrected QT dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio values among the pretransplant and 3-, 6-, and 12-month posttransplant measurements (P < .001 for all comparisons). However, the values of these measurements in the transplant group at 12 months were significantly higher than baseline values of the control group (P < .001 for all comparisons).

CONCLUSIONS

P-wave dispersion, corrected QT dispersion, T-wave peak-end interval, and T-wave peak-end/corrected QT ratio were shown to be attenuated after transplant, although they remained higher than baseline measurements in healthy individuals. These results indirectly offer that there may be a reduction in risk of atrial fibrillation and ventricular arrhythmias after transplant.

Renal sympathetic denervation guided by renal nerve stimulation to treat ventricular arrhythmia in CKD patients with ICD

Chronic kidney disease (CKD) patients on stage 4 present greater risk rates for malignant ventricular arrhythmia events. This study examined patients with CKD in stages 1, 2, 3 and 4, left ventricular dysfunction and automatic implantable cardioverter-defibrillator (ICD). Our goal was to record the appropriate therapies, "Anti-tachycardia Therapy Pacing" (ATP) and shock events during the 18 months of follow-up and compare the incidence and severity of these at different stages of CKD, mainly in patients with CKD stage 4 underwent renal sympathetic denervation (RSD) guided by renal nerve stimulation (RNS). One hundred and fifteen patients were evaluated once every three months till 18 months of follow-up. The arrhythmic events were assessed at each follow-up visit. Comparing the groups, we can see the number of ATP and shock events recorded by ICD during 18 months of follow-up, and differences in the number of therapeutic events between the various stages of CKD. The hazard ratio (HR), 95% confidence interval (CI) and P value for ATP and shock events between all the CKD stages were evaluated by the log-rank/Mantel-Haenszel test. At the 18th month of follow-up, 75% of patients with CKD stage 4 received ATP, and 70% were treated with shock while only 20% of the subjects with CKD stage 4 that were submitted to RSD received ATP and 20% were treated with shock, P<0.0001 and P=0.0002, respectively. In our study, a decline occurred in the incidence of arrhythmias, and therefore, appropriate ICD therapies in advanced stages of CKD, reducing the risk rates for these events in patients with CKD on stage 4 after RSD guided by RNS in comparison to the other CKD stages. Our results suggest that RSD can control the higher incidence of malignant arrhythmias in advanced CKD stages.