P-wave duration in lead aVR and the risk of atrial fibrillation in hypertension.

BACKGROUND: Hypertension entails atrial remodeling that affect P-wave (PW) duration on electrocardiogram (ECG). PW indices (e.g., variance, dispersion, and terminal force) are associated with a higher risk for atrial fibrillation (AF), but their calculation requires multiple measurements of PW duration, limiting their use in clinical practice. We evaluated whether PW duration in specific ECG leads may identify patients with increased susceptibility to AF in a population of hypertensive patients. METHODS: In a case-control study, AF and control subjects were matched for age, sex, and left atrial (LA) dimensions. PW duration was measured from digitally stored ECGs. Logistic regression was used to assess the association of PW duration and indices with AF. RESULTS: We enrolled 44 hypertensive AF patients (16 paroxysmal and 28 persistent) and 44 hypertensive controls. AF and control subjects were matched for sex (males, n = 27), age (67 ± 8 years), LA diameter (40 ± 5 mm), and were comparable for left ventricular mass (45 ± 11 g/m(2.7) vs 48 ± 12 g/m(2.7) , P = 0.19), ejection fraction (58 ± 7% in both groups), and prevalence of mild valvular heart disease (7% vs 5%; P = 0.64). PW duration in lead aVR was significantly higher in AF patients as compared with controls (115 ± 18 ms vs 101 ± 14 ms; P < 0.0001) and was the best independent predictor of AF in multivariable logistic regression (PW ≥ 100 ms: RR = 3.7; 95% CI: 1.3-10.3; P = 0.02). CONCLUSIONS: Simple measurement of PW duration in lead aVR allows effective identification of AF patients in a population of hypertensives. Confirmation of this finding in a larger population would provide a simple and effective risk marker of AF in hypertensive patients.

Osteopontin and galectin-3 predict the risk of ventricular tachycardia and fibrillation in heart failure patients with implantable defibrillators.

BACKGROUND: Myocardial extracellular matrix remodelling provides electrical heterogeneity entailing ventricular tachycardia/fibrillation (VT/VF) in heart failure (HF) patients. Osteopontin (OPN) and Galectin-3 (Gal-3) are fibrosis markers and may reflect the extension of the arrhythmogenic substrate. We assessed whether plasma OPN and Gal-3 predict the risk of sustained VT/VF in a cohort of HF patients with implantable cardioverter-defibrillator (ICD). METHODS: A total of 75 HF patients underwent pre-ICD implantation clinical evaluation and assessment of plasma OPN and Gal-3. The primary endpoint was the time to the occurrence of the first sustained VT/VF. Hazard ratios (HR) were derived from Cox proportional-hazards analysis. RESULTS: Patients with coronary artery disease (CAD) had higher plasma OPN (79.8 ± 44.0 ng/mL vs. 66.0 ± 31.8 ng/mL; P = 0.04). Both Gal-3 (r = -0.38; P = 0.01) and OPN (r = -0.27; p = 0.01) were negatively related to estimated glomerular filtration rate. After 29 ± 17 months, 20 patients (27%) reached the primary endpoint. Patients with VT/VF had higher plasma OPN and Gal-3 (97.4 ± 51.7 ng/mL vs. 65.9 ± 31.3 ng/mL; P = 0.002 and 19.7 ± 8.5 ng/mL vs. 16.2 ± 6.2 ng/mL; P = 0.05). In univariate analysis, OPN (log-OPN, HR: 32.4; 95%CI: 3.9-264.7; P = 0.001) and Gal-3 (HR: 1.05; 95%CI: 1.00-1.11; P = 0.04) predicted sustained VT/VF. In multivariable analysis, both OPN (HR: 41.4; 95%CI: 3.8-441.9; P = 0.002) and Gal-3 (HR: 1.06; 95%CI: 1.00-1.12; P = 0.03) retained their prognostic power after correction for age, sex, history of MI, EF, NYHA class, eGFR, use of ACE-I, and amiodarone. CONCLUSIONS: Plasma OPN and Gal-3 predict sustained VT/VF in HF patients at high risk for SCD. Larger prospective studies should outline the role of these biomarkers in predicting SCD on top of conventional risk stratification.

Atrial natriuretic Peptide single nucleotide polymorphisms in patients with nonfamilial structural atrial fibrillation.

BACKGROUND: Atrial natriuretic peptide (ANP) has antihypertrophic and antifibrotic properties that are relevant to AF substrates. The -G664C and rs5065 ANP single nucleotide polymorphisms (SNP) have been described in association with clinical phenotypes, including hypertension and left ventricular hypertrophy. A recent study assessed the association of early AF and rs5065 SNPs in low-risk subjects. In a Caucasian population with moderate-to-high cardiovascular risk profile and structural AF, we conducted a case-control study to assess whether the ANP -G664C and rs5065 SNP associate with nonfamilial structural AF. METHODS: 168 patients with nonfamilial structural AF and 168 age- and sex-matched controls were recruited. The rs5065 and -G664C ANP SNPs were genotyped. RESULTS: The study population had a moderate-to-high cardiovascular risk profile with 86% having hypertension, 23% diabetes, 26% previous myocardial infarction, and 23% left ventricular systolic dysfunction. Patients with AF had greater left atrial diameter (44 ± 7 vs. 39 ± 5 mm; P < 0.001) and higher plasma NTproANP levels (6240 ± 5317 vs. 3649 ± 2946 pmol/mL; P < 0.01). Odds ratios (ORs) for rs5065 and -G664C gene variants were 1.1 (95% confidence interval [CI], 0.7-1.8; P = 0.71) and 1.2 (95% CI, 0.3-3.2; P = 0.79), respectively, indicating no association with AF. There were no differences in baseline clinical characteristics among carriers and noncarriers of the -664C and rs5065 minor allele variants. CONCLUSIONS: We report lack of association between the rs5065 and -G664C ANP gene SNPs and AF in a Caucasian population of patients with structural AF. Further studies will clarify whether these or other ANP gene variants affect the risk of different subphenotypes of AF driven by distinct pathophysiological mechanisms.

Common genetic variants in selected Ca²âº signaling genes and the risk of appropriate ICD interventions in patients with heart failure.

PURPOSE: Defective Ca²âº handling in failing cardiomyocites predisposes patients with heart failure (HF) to ventricular arrhythmia. We investigated whether gene variants of Ca²âº handling proteins are associated with the occurrence of ventricular tachycardia/fibrillation (VT/VF) in HF patients implanted with a primary prevention implantable cardioverter-defibrillator (ICD). METHODS: One hundred thirty-six patients with HF were followed from ICD implantation to the time of first appropriate ICD intervention for VT > 170 bpm. The following polymorphisms were genotyped: ATP2A2 rs1860561 and rs56243033; RYR2 rs4142933; CASQ2 rs4074536; SLC8A1 g.-23449C > A; PLN rs12198461; FKBP1B rs7568163. Hazard ratios (HR) were derived from Cox proportional-hazards regression analysis. RESULTS: After a mean follow-up of 879 days (IQ range, 327 to 1,459), 34 patients (25%) had appropriate ICD intervention. Non-sustained VT (HR, 2.12; 95%CI, 0.87-5.19; p = 0.09) and atrial fibrillation (AF) at ICD implantation (HR, 2.33; 95%CI, 0.89-6.10; p = 0.08) predicted appropriate ICD interventions with borderline statistical significance. Prevalence of ATP2A2 rs1860561 variant was 17% in patients without VT/VF and 4% in those with ventricular arrhythmia (p = 0.009). After adjustment for AF and NSVT, the rs1860561 A mutant allele independently predicted lower incidence of VT/VF (HR, 0.29; 95%CI, 0.09-0.98; p = 0.04). CONCLUSIONS: The observation that ATP2A2 rs1860561 gene variant associated with lower risk of life-threatening arrhythmia in HF patients suggests that selected calcium gene variants may modify the risk of SD even within the complex and polygenic pathological condition of HF. Combining traditional risk factors and genetic profiling could reveal helpful to identify HF patients who will benefit most from ICD implantation.