Left atrium remodeling predicts late recurrence of paroxysmal atrial fibrillation after second generation cryoballoon ablation

Background

Atrial fibrillation (AF) is the most common arrhythmia worldwide. Nowadays, AF ablation is a valuable treatment option. It has been shown that the left atrium (LA) diameter is a predictor of AF recurrence after cryoballoon ablation (CBA). Since it does not reflect the true LA size, we compared the role of different LA anatomical parameters using echocardiography for the prediction of AF recurrence after CBA.

Methods

We retrospectively included 209 patients (mean age 56.1?±?13.6 years, male 62%) with paroxysmal AF undergoing CBA. A transthoracic echocardiography was performed in all patients.

Results

At a mean follow-up of 16.9?±?6.3 months, AF recurred in 25.4% of the patients. LA anterior - posterior diameter (LAD), LA minimum volume (LAmin) and early AF recurrence were independent predictors of recurrence. Based on receiver operating characteristics, cut – off values for LAD and, LAmin were 41 mm, 23.69 mL, respectively. The negative predictive values for recurrence were 73% and 87.3% respectively. In patients with AF recurrence, a significant proportion (30.2%) showed LA longitudinal remodeling (LA superior – inferior diameter) even though classically measured LAD was normal.

Conclusions

Longitudinal LA remodeling plays an additional role for predicting AF recurrence after CBA, in patients without LAD dilation. Moreover, LAmin had a high negative predictive value and was an independent predictor of AF recurrence. Therefore, a more complete LA anatomical assessment allows a better prediction of AF recurrences after CBA.

     

A Novel Electrocardiographic Index for the Diagnosis of Diastolic Dysfunction

Background

Although the assessment of diastolic dysfunction (DD) is an integral part of routine cardiologic examinations, little is known about associated electrocardiographic (ECG) changes. Our aim was to investigate a potential role of ECG indices for the recognition of patients with DD.

Methods and Results

ECG parameters correlating with echocardiographic findings of DD were retrospectively assessed in a derivation group of 172 individuals (83 controls with normal diastolic function, 89 patients with DD) and their diagnostic performance was tested in a validation group of 50 controls and 50 patients. The patient group with a DD Grade 1 and 2 showed longer QTc (422±24ms and 434±32ms vs. 409±25ms, p<0.0005) and shorter Tend–P and Tend–Q intervals, reflecting the electrical and mechanical diastole (240±78ms and 276±108ms vs. 373±110ms, p<0.0001; 409±85ms and 447±115ms vs. 526±119ms, p<0.0001). The PQ–interval was significantly longer in the patient group (169±28ms and 171±38ms vs. 153±22ms, p<0.005). After adjusting for possible confounders, a novel index (Tend–P/[PQxAge]) showed a high performance for the recognition of DD, stayed robust in the validation group (sensitivity 82%, specificity 93%, positive predictive value 93%, negative predictive value 82%, accuracy 88%) and proved a substantial added value when combined with the indexed left atrial volume (LAESVI, sensitivity 90%, specificity 92%, positive predictive value 95%, negative predictive value 86%, accuracy 91%).

Conclusions

A novel electrocardiographic index Tend–P/(PQxAge) demonstrates a high diagnostic accuracy for the diagnosis of DD and yields a substantial added value when combined with the LAESVI.     

Triglycerides impair postischemic recovery in isolated hearts: roles of endothelin-1 and trimetazidine

There is growing evidence that hypertriglyceridemia exacerbates ischemic injury. We tested the hypothesis that triglycerides impair myocardial recovery from low-flow ischemia in an ex vivo model and that such an effect is related to endothelin-1. Hyperglycemic (glucose concentration = 12 mmol/l) and hyperinsulinemic (insulin concentration = 1.2 micromol/l) isolated rat hearts were perfused with Krebs-Henseleit buffer (PO(2) = 670 mmHg, pH 7.4, 37 degrees C) added with increasing triglycerides (0, 1,000, 2,000, and 4,000 mg/dl, n = 6-9 rats/group). Hearts were exposed to 60 min of low-flow ischemia (10% of basal coronary flow), followed by 30 min of reperfusion. We found that increasing triglycerides impaired both the diastolic (P < 0.005) and systolic (P < 0.02) recovery. The release of endothelin-1 during reperfusion increased linearly with triglyceride concentration (P = 0.0009). Elevated triglycerides also increased the release of nitrite and nitrate (NO(x)), the end products of nitric oxide, up to 6 micromol/min. Trimetazidine (1 micromol) further increased NO(x) release, blunted endothelin-1 release, and protected myocardial function during recovery. We conclude that high triglyceride levels impair myocardial recovery after low-flow ischemia in association with endothelin-1 release. The endothelium-mediated effect of triglycerides on both contractile recovery and endothelin-1 release is prevented by 1 microM trimetazidine.     

Leadless pacing in a young patient with cardioinhibitory vasovagal syncope

Vasovagal syncope is characterized by vasodilatation and/or bradycardia and thereby a fall in arterial BP and global cerebral perfusion in response to a trigger. Although it is a benign condition, patients with frequent and traumatic episodes need treatment in order to improve quality of life. We describe the case of a 17-years-old boy suffering from cardioinhibitory syncope. At the end of a complete negative cardiac and neurological examination, a loop recorder was implanted. During the subsequent follow-up the ILR documented a 9-s pause. To improve the patient's compliance, and considering cardioinhibitory syncope as a temporary condition, a leadless pacemaker was eventually implanted.     

Role of platelet and vascular eicosanoids in the pathophysiology of ischemic heart disease

The role of platelet and vascular arachidonate metabolism in ischemic heart disease can be derived from direct measurements and/or inhibitor trials. Direct measurements have yielded somewhat conflicting results, largely related to analytical problems and ex vivo platelet activation during blood sampling. On the other hand, inhibitor trials have clearly established the following: 1) thromboxane (TX) A2-dependent platelet activation plays an important role in the dynamic process of coronary thrombosis in unstable angina, 2) TXA2 does not appear to mediate coronary vasospasm, as seen in variant angina, 3) endogenous prostacyclin (PGI2) is not released in response to myocardial ischemia and is unlikely to regulate coronary blood flow, and 4) exogenous PGI2 is of limited therapeutic benefit. The demonstration that low-dose aspirin (0.5-1.0 mg/(kg X day] is a selective inhibitor of TXA2-dependent platelet function provides a conceptual and practical framework for the rational design of future trials. Moreover, the identification of major enzymatic metabolites of TXB2 in plasma (11-dehydro-TXB2) and urine (2,3-dinor-TXB2) and development of appropriate analytical techniques offer the opportunity for better defining the pathophysiological role of TXA2 in humans.     

Prostacyclin does not affect insulin secretion in humans

The effects of Prostacyclin (PGI₂) infusion on insulin secretion and glucose tolerance were investigated in 7 healthy subjects. PGI₂ infusion caused no statistically significant changes of either glucose or insulin concentration, over the range 2.5–20 ng/Kg/min. A constant PGI₂ infusion (10 ng/Kg/min) did not inhibit acute insulin responses to a glucose (20 g i.v.) pulse (response before PGI₂ = 612±307%; during PGI₂ = 515±468%, mean ± SD, mean change 3–5 min insulin, % basal; P=NS). Glucose disappearance rates were similar after the first and second glucose pulse.Thus, in contrast to PGE₂, PGI₂ does not affect insulin secretion nor glucose disposal at doses producing platelet and vascular changes. It is hypothesized that an altered PGI₂/PGE₂ balance in diabetes may represent a link between vascular, platelet and metabolic changes.     

Cryoballoon Ablation for Paroxysmal Atrial Fibrillation in Septuagenarians: a Prospective Study

Aims

To evaluate the effects of pulmonary vein isolation (PVI) in terms of feasibility, safety and success rate on a midterm follow-up period in septuagenarians undergoing ablation with the Arctic Front Cryoballoon for atrial fibrillation (AF).

Methods and Results

We prospectively enrolled 21 patients aged 70 years or older (14 male; age 73 ± 2.5 years) elected to circumferential PVI with the 28mm cryoballoon for symptomatic drug resistant paroxysmal AF. A total number of 82 pulmonary veins (PV) were evidenced. Successful isolation could be obtained in all 82 (100%) PV ostia at the end of procedure. No major complication occurred during procedure. At a mean follow-up of 11.5 ± 4.7 months following ablation, 62% of patients did not present recurrence of atrial arrhythmias.

Conclusion

Cryoballoon ablation may be feasible and safe in older patients. Moreover a large proportion of the latter did not present AF recurrence during follow-up.