Electrocardiographic changes during induced therapeutic hypothermia in comatose survivors after cardiac arrest

AIM: To assess the safety of therapeutic hypothermia(TH) concerning arrhythmias we analyzed serial electrocardiograms(ECG) during TH.METHODS: All patients recovered from a cardiac arrest with Glasgow < 9 at admission were treated with induced mild TH to 32-34℃. TH was obtained with cool fluid infusion or a specific intravascular device. Twelvelead ECG before,during,and after TH,as well as ECG telemetry data was recorded in all patients. From a total of 54 patients admitted with cardiac arrest during the study period,47 patients had the 3 ECG and telemetry data available. ECG analysis was blinded and performed with manual caliper by two independent cardiologists from blinded copies of original ECG,recorded at 25 mm/s and 10 mm/m V. Coronary care unit staff analyzed ECG telemetry for rhythm disturbances. Variables measured in ECG were rhythm,RR,PR,QT and corrected QT(QTc by Bazett formula,measured in lead v2) intervals,QRS duration,presence of Osborn's J wave and U wave,as well as ST segment displacement and T wave amplitude in leads Ⅱ,v2 and v5.RESULTS: Heart rate went down an average of 19 bpm during hypothermia and increased again 16 bpm with rewarming(P < 0.0005,both). There was a nonsignificant prolongation of the PR interval during TH and a significant decrease with rewarming(P = 0.041). QRS duration significantly prolonged(P = 0.041) with TH and shortened back(P < 0.005) with rewarming. QTc interval presented a mean prolongation of 58 ms(P < 0.005) during TH and a significant shortening with rewarming of 22.2 ms(P = 0.017). Osborn or J wave was found in 21.3% of the patients. New arrhythmias occurred in 38.3% of the patients. Most frequent arrhythmia was non-sustained ventricular tachycardia(19.1%),followed by severe bradycardia or paced rhythm(10.6%),accelerated nodal rhythm(8.5%) and atrial fibrillation(6.4%). No life threatening arrhythmias(sustained ventricular tachycardia,polymorphic ventricular tachycardia or ventricular fibrillation) occurred during TH. CONCLUSION: A 38.3% of patients had cardiac arrhythmias during TH but without life-threatening arrhythmias. A concern may rise when inducing TH to patients with long QT syndrome.

Incretins and selective renal sodium-glucose co-transporter 2 inhibitors in hypertension and coronary heart disease

Hyperglycemia is associated with an increased risk of cardiovascular disease,and the consequences ofintensive therapy may depend on the mechanism of the anti-diabetic agent(s)used to achieve a tight control.In animal models,stable analogues of glucagon-like peptide-1(GLP-1)were able to reduce body weight and blood pressure and also had favorable effects on ischemia following coronary reperfusion.In a similar way,dipeptidyl peptidase IV(DPPIV)showed to have favorable effects in animal models of ischemia/reperfusion.This could be due to the fact that DPPIV inhibitors were able to prevent the breakdown of GLP-1 and glucose-dependent insulinotropic polypeptide,but they also decreased the degradation of several vasoactive peptides.Preclinical data for GLP-1,its derivatives and inhibitors of the DPPIV enzyme degradation suggests that these agents may be able to,besides controlling glycaemia,induce cardio-protective and vasodilator effects.Notwithstanding the many favorable cardiovascular effects of GLP-1/incretins reported in different studies,many questions remain unanswered due the limited number of studies in human beings that aim to examine the effects of GLP-1 on cardiovascular endpoints.For this reason,long-term trials searching for positive cardiovascular effects are now in process,such as the CAROLINA and CARMELINA trials,which are supported by small pilot studies performed in humans(and many more animal studies)with incretin-based therapies.On the other hand,selective renal sodium-glucose co-transporter 2 inhibitors were also evaluated in the prevention of cardiovascular outcomes in type 2 diabetes.However,it is quite early to draw conclusions,since data on cardiovascular outcomes and cardiovascular death are limited and long-term studies are still ongoing.In this review,we will analyze the mechanisms underlying the cardiovascular effects of incretins and,at the same time,we will present a critical position about the real value of these compounds in the cardiovascular system and its protection.

Takotsubo syndrome:Advances in the understanding and management of an enigmatic stress cardiomyopathy

Takotsubo cardiomyopathy is a syndrome mimicking an acute myocardial infarction in absence of obstructive epicardial coronary artery disease to explain the degree of the wall motion abnormalities. Typically more common in the elderly women, this condition is usually triggered by unexpected emotional or physical stress situations, and is associated with electrocardiogram abnormalities and slight elevation of cardiac biomarkers. The pathophysiological mechanism is not clear yet, but it is believed that a high circulating concentration of catecholamines causes an acute dysfunction of the coronary microcirculation and metabolism of cardiomyocytes, leading to a transient myocardial stunning. Typically, it presents with acute left ventricular systolic dysfunction that in most cases is completely resolved at short term. Recurrences are rare and it is thought that the long-term prognosis is good. We present here a review of the clinical features, pathophysiology and management of this enigmatic condition.

急性心肌梗死后参数成像定量心肌声学造影识别心肌顿抑

Microvascular integrity demonstrated by myocardial contrast echocardiography(MCE) predicts functional recovery after an acute myocardial infarction(AMI). Recently, parametric imaging-based quantitative MCE has been developed. Our aim was to assess the usefulness of parametric imaging-based quantitative MCE parameters to predict the functional recovery of akinetic segments after primary percutaneous transluminal coronary angioplasty(PTCA). Fifty-three consecutive patients with a first AMI were enrolled. They underwent primary PTCA. Standard echocardiography and real-time MCE were performed. Qualitative analysis and parametric imaging-based quantitative parameters were measured offline by different blinded investigators. Dobutamine stress echocardiography was performed 1 month later. A new standard echocardiogram to assess the functional status of the akinetic segments and coronary angiography to evaluate the presence of restenosis at the level of the culprit lesion were performed 6 months later. The mean patient age was 62.9±14 years, and 42 were men(79%); 170 segments were akinetic. Of these, 105(62%) recovered their function. The best parameter to predict functional recovery was the myocardial blood flow velocity(β). These results were better than those obtained using dobutamine stress echocardiography and qualitative MCE to predict functional recovery. In conclusion, parametric imaging-based quantitative MCE is an accurate diagnostic tool to detect stunned myocardium after AMI. Its diagnostic accuracy in predicting the functional recovery of akinetic segments after primary PTCA is better than the accuracy of dobutamine stress echocardiography and qualitative MCE.

Giant and thrombosed left ventricular aneurysm

Left ventricular aneurysms are a frequent complication of acute extensive myocardial infarction and are most commonly located at the ventricular apex. A timely diagnosis is vital due to the serious complications that can occur,including heart failure,thromboembolism,or tachyarrhythmias. We report the case of a 78-yearold male with history of previous anterior myocardial infarction and currently under evaluation by chronic heart failure. Transthoracic echocardiogram revealed a huge thrombosed and calcified anteroapical left ventricular aneurysm. Coronary angiography demonstrated that the left anterior descending artery was chronically occluded,and revealed a big and spherical mass with calcified borders in the left hemithorax. Left ventriculogram confirmed that this spherical mass was a giant calcified left ventricular aneurysm,causing very severe left ventricular systolic dysfunction. The patient underwent cardioverter-defibrillator implantation for primary prevention.

Compression of Left Main Coronary Artery in Patients with Pulmonary Artery Aneurysm and Pulmonary Hypertension

Background: Pulmonary artery aneurysm (PAA) is an unusual finding and its association with left main coronary (LMCA) compression is even more infrequent. Cardiac CT evaluates of presence and size of PAA and the degree of LMCA compression. The aim of this study is to describe two cases of adults with compression of LMCA with PAA associated with PDA and pulmonary hypertension. Case presentation: The first case is a 27-year-old man with PAA (78 mm diameter) and LMCA compression of 70% between the aortic sinus and the PAA. He presented angina as a manifestation of the LMCA compression. During follow-up the patient died. The second case is a 28-year-old man with PAA (110 mm diameter) that compresses LMCA in 55%, he rejected surgical treatment, but he is in close follow-up with medical treatment. Conclusion: Cardiac computed tomography played an important role both in the diagnosis and identification of high-risk PAA patients.

Brugada electrocardiographic pattern induced by fever

Brugada syndrome is a major cause of sudden death in young adults.Fever has been described to induce a Brugada-type electrocardiogram in asymptomatic patients with a negative family history,to disclose Brugada syndrome and to increase the risk of death and induce T wave alternans in patients with diagnosed Brugada syndrome.Risk stratification is challenging and demands a careful evaluation.Here we present 2 case reports and review the literature.