A28-5 Assessment of rhythm discrimination by QRS morphology analysis in single and dual chamber cardioverter defibrillators

Introduction: Atrial fibrillation (AF) is responsible for substantial morbidity and mortality, yet little is known about the environmental factors that may trigger AF episodes. Weather has been proposed as a potential precipitant of paroxysmal AF. Hypothesis: We assessed the hypothesis that changes in outdoor ambient temperature and outdoor absolute humidity may trigger paroxysmal AF in the following 24 hours. Methods: Patients with dual chamber implantable cardioverter defibrillators (ICDs) living in eastern Massachusetts were enrolled between September 2006 and March 2010 from the Tufts Medical Center Cardiac Arrhythmia Clinic (Boston, Massachusetts) and followed prospectively for episodes of paroxysmal AF lasting at least 30 seconds. Arrhythmias documented by the ICD were reviewed and interpreted by an electrophysiologist masked to exposure. The date and time of AF episodes were linked to hourly weather data measured at Boston Logan International Airport. We examined the hypothesis using a time-stratified case-crossover analysis matched on calendar month, day of week and time of day and adjusted for air pollution and barometric pressure. To reduce the possibility of over-representation of clustered events and to reflect the averaging time of the exposure, incident AF episodes were included in the analysis if at least 24 hours had passed since the previous AF episode. Results: Of 200 patients enrolled, 49 experienced at least one AF episode (n = 328 episodes). After excluding events with missing exposure or covariate information, analyses were confined to 230 AF episodes among 47 patients. The 47 patients with paroxysmal AF were followed for an average of 1.9 years, and 32 (68%) were male, 45 (96%) were Caucasian, the mean age was 67 years, 24 (51%) had a history of prior AF episodes, 27 (57%) had a pre-implantation ejection fraction < 35%, and 29 (62%) received the ICD for primary prophylaxis. Outdoor temperature in the previous 24 hours was not associated with AF (odds ratio (OR) = 1.13; 95% confidence interval (CI): 0.89, 1.43, p = 0.32, per interquartile range (IQR) decrease of 6.3°C). Lower absolute humidity in the previous 24 hours was associated with a higher risk of AF onset (OR = 1.33; 95% CI: 1.02, 1.74, p = 0.04, per IQR decrease of 3.5 g/m 3 ); this risk increased slightly for the previous 3 hours (OR = 1.39; 95% CI: 1.06, 1.82, p = 0.02, per IQR decrease of 3.7 g/m 3 ). Conclusions: In conclusion, drier air was associated with a transiently higher risk of paroxysmal AF in the following 24 hours among patients with dual chamber ICDs.

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Ventriculoatrial conduction metrics for classification of ventricular tachycardia with 1: 1 retrograde conduction in dual-chamber sensing implantable cardioverter defibrillators

Journal of Electrocardiology ◽

10.1016/s0022-0736(98)90309-0 ◽

1998 ◽

Vol 31 ◽

pp. 152-156 ◽

Cited By ~ 2

Author(s):

Julie A Thompson ◽

Janice M Jenkins

Keyword(s):

Ventricular Tachycardia ◽

Implantable Cardioverter Defibrillators ◽

Dual Chamber ◽

Cardioverter Defibrillators ◽

Retrograde Conduction

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P2878Higher all-cause mortality in patients with implanted dual-chamber cardioverter-defibrillators for secondary prevention: an analysis from the Polish ICD Registry

European Heart Journal ◽

10.1093/eurheartj/ehz748.1186 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

I Warchol ◽

A Lubinski ◽

M Sterlinski ◽

O Kowalski ◽

K Goscinska-Bis ◽

...

Keyword(s):

Secondary Prevention ◽

Implantable Cardioverter Defibrillators ◽

Dual Chamber ◽

Single Chamber ◽

Kaplan Meier ◽

Significant Difference ◽

All Cause Mortality ◽

National Cohort ◽

Cardioverter Defibrillators

Abstract Background In the Polish ICD Registry population secondary prevention recipients account for over 27%. Despite the evolution of indications for secondary prevention implantable cardioverter defibrillators (ICDs), recommendations regarding the use of ICDs for secondary prevention of sudden cardiac death (SCD) rely on information from a small number of randomized controlled trials that were performed decades ago, with mixed results. Moreover, research on the outcomes after implantations for secondary prevention of ICDs is limited. While dual-chamber devices offer theoretical advantage over single-chamber devices, dual-chamber ICDs (DC-ICDs) were announced not superior to single-chamber (SC-ICDs) in some research. Purpose Therefore, the aim of the study was to evaluate the all-cause mortality among patients from the Polish ICD Registry receiving either a single- or a dual-chamber device for secondary prevention in contemporary clinical practice. Methods All patients enrolled in the Polish ICD Registry from 1995 to 2016 were identified. Patients were included in the study if they were designated as receiving an ICD for secondary prevention of SCD after documented tachycardic arrest, sustained ventricular tachycardia (VT), or syncope. Kaplan-Meier survival analysis was used to assess all-cause mortality. Results In the study population of 3596 ICD recipients (mean age 69±12 years, 81% male, SC-ICD 61%, DC-ICD 39%), during mean follow-up of 79±43 months all-cause mortality rate was higher in the dual-chamber group than in the single chamber group, with a significant difference between the two groups as depicted in Kaplan-Meier curve (p<0,05). The median survival time was 98 months versus 110 months for SC and DC-ICD, respectively. Conclusions This study is the first to describe the characteristics of a national cohort of patients receiving a secondary prevention ICD in such a long follow-up period in contemporary practice. Implantation of a dual-chamber ICD was associated with higher all-cause mortality compared with single chamber devices.

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