Objectives The purposes of this study were to examine left atrial (LA) functional reserve in patients with heart failure (HF) with preserved ejection fraction (HFpEF) and to determine whether LA ...strain has an incremental diagnostic value over clinical and conventional echocardiographic parameters. Background Patients with HFpEF have multiple cardiovascular reserve abnormalities. Although the LA is dysfunctional in HFpEF, the diagnostic value of LA strain remains unknown. Methods The LA at rest and during passive leg lifts was echocardiographically assessed in 40 patients with HFpEF and in 46 patients with hypertension without HF (HT controls). Global peak atrial longitudinal strain during ventricular systole (global LAS ) and booster strain during atrial contraction (global LAB ) were assessed using speckle tracking. Results Patients with HFpEF had an enlarged LA and reduced LA emptying fraction compared with HT controls at rest, while LA stroke volume (SV) was similar between the groups. During leg lifts, increases in LA reservoir and contractile function (i.e., global LAS and LAB ) were blunted in HFpEF patients compared with HT controls, resulting in impaired LASV responses. Global LAS and LAB during leg lifts accurately differentiated HFpEF from HT controls (areas under the curve: 0.95 and 0.92, respectively). Resting global LAS had a significant incremental diagnostic value over clinical (age and sex) and conventional echocardiographic parameters (E/E′ ratio, left ventricular mass index, and maximum LA volume index) (global chi-square: 49.6 vs. 30.8; p < 0.0001). The diagnostic value was further improved by adding global LAS during leg lifts (global chi-square: 72.2 vs. 49.6; p < 0.0001). Conclusions An enlarged LA compensates for LA dysfunction and maintains LASV at rest in patients with HFpEF. However, depressed LA reserve affects LA performance during leg lifts. Evaluation of LA function, including LA strain using leg lifts, might provide incremental diagnostic value for HFpEF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract Background Several KCNQ1 splicing mutations have been identified in patients with type-1 long QT syndrome (LQT1). It was suggested that the clinical severity may differ according to the ...aberrant splicing products. There may be precipitating factors that cause cardiac events in those with a mild clinical phenotype (forme fruste LQT1). Methods and results We analyzed the KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 genes in 31 consecutive LQTS patients. A novel KCNQ1 1251+1G>A (IVS9+1G>A) mutation was identified in three probands and their two relatives. The QT interval in all of the five individuals with mutation was not much prolonged in the absence of precipitating factors (mean QTc was 461 ± 30 ms.). Two of the five individuals with mutation were symptomatic. One patient (a 38-year-old female) had experienced recurrent episodes of syncope due to ventricular tachyarrhythmias (VTAs) accompanied by QT prolongation (QTc: 750 ms) when the serum potassium concentration (K+ ) was 2.7 mEq/L. After correction of K+ , the QTc interval was shortened to 515 ms, and the occurrence of VTAs ceased. Another patient (a 22-year-old female) was resuscitated from cardio-pulmonary arrest due to VTAs. Just after resuscitation, the QTc interval was 629 ms, and K+ was 2.9 mEq/L. After correction of K+ , the QTc interval was dramatically shortened to 440 ms. In order to identify abnormal splicing products of the responsible mutation, we analyzed the reverse transcription-polymerase chain reaction products from peripheral bloods of the mutation carrier, and identified exon 9-skipping (Δ9) and cryptic sequential exons 8 and 9-skipping (Δ8–9) products, as well as a no exon-skipping product. Conclusions We identified a novel KCNQ splicing mutation 1251+1G>A in forme fruste LQT1, which induces cryptic splicing. Two of the five individuals with mutation experienced VTAs in the setting of hypokalemia, emphasizing the need to increase awareness of the significance of hypokalemia in this subgroup of LQT1 patients.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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