The prognostic impact of pre-implantation hyponatremia on morbidity and mortality among patients with left ventricular dysfunction and implantable cardioverter-defibrillators.

Abstract

AIMS:

Hyponatremia is commonly observed among patients with left ventricular (LV) dysfunction and is a marker for adverse outcomes. We aimed to determine the prognostic significance of pre-implant hyponatremia on the outcomes of death, acute decompensated heart failure (ADHF) and appropriate implantable cardioverter-defibrillator (ICD) therapy for ventricular arrhythmias among patients with ICDs.

METHODS AND RESULTS:

The study population consisted of patients with an ejection fraction ≤40% undergoing ICD implantation (n = 911) for the primary or secondary prevention of sudden cardiac death from 1997 to 2007. The predictive value of the severity of pre-implantation hyponatremia stratified into mild hyponatremia (n = 268, sodium 134-136 mmol/L), moderate hyponatremia (n = 105, sodium 131-133 mmol/L), and severe hyponatremia (n = 31, sodium ≤130 mmol/L) on the risk of death, ADHF, and appropriate ICD therapy for ventricular arrhythmias as compared with patients a normal serum sodium (n = 507, sodium ≥ 137 mmol/L), was calculated using multivariable Cox proportional hazards analyses. During a mean follow-up of 775 ± 750 days as the severity of hyponatremia (from a normal sodium to severe hyponatremia) increased an incremental incidence of death (25% to 61%, P < 0.001) and ADHF (11% to 26%, P = 0.004) was observed with a reduced incidence of ICD therapy for ventricular tachycardia/ventricular fibrillation (37-29%, P = 0.037). Compared with the normal sodium cohort, patients with severe hyponatremia demonstrated an increased risk of death [adjusted hazard ratio (AHR) 2.69 (95% confidence interval, CI 1.57-4.59), P = 0.004] and ADHF [AHR 2.98 (95% CI 1.41-6.30), P = 0.004], with a lower probability of appropriate ICD therapy [AHR 0.68 (95% CI 0.27-0.88), P = 0.031].

CONCLUSION:

Hyponatremia is commonly observed among ICD recipients with LV dysfunction. Patients with an increasing severity of hyponatremia are at increased risk of death and HF related morbidity with a reduced incidence of appropriate ICD therapy particularly among patients with severe hyponatremia.

• Authors: Sanjeev P Bhavnani, Anupam Kumar, Craig I Coleman, Danette Guertin, Ravi K Yarlagadda, Christopher A Clyne, Jeffrey Kluger
• Journal: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology (Europace) Vol. 16 Issue 1 Pg. 47-54 (Jan 2014) ISSN: 1532-2092 [Electronic] England
• PMID: 23954920 (Publication Type: Controlled Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Aged
• Comorbidity
• Connecticut
• Defibrillators, Implantable (statistics & numerical data)
• Female
• Heart Failure (mortality, prevention & control)
• Humans
• Hyponatremia (diagnosis, mortality)
• Incidence
• Male
• Preoperative Care (methods, statistics & numerical data)
• Prognosis
• Prosthesis Implantation (mortality)
• Risk Assessment
• Survival Analysis
• Treatment Outcome
• Ventricular Dysfunction, Left (mortality, prevention & control)