Inducibility of ventricular fibrillation during mild therapeutic hypothermia: electrophysiological study in a swine model.

INTRODUCTION: Mild therapeutic hypothermia (MTH) is being used after cardiac arrest for its expected improvement in neurological outcome. Safety of MTH concerning inducibility of malignant arrhythmias has not been satisfactorily demonstrated. This study compares inducibility of ventricular fibrillation (VF) before and after induction of MTH in a whole body swine model and evaluates possible interaction with changing potassium plasma levels. METHODS: The extracorporeal cooling was introduced in fully anesthetized swine (n = 6) to provide MTH. Inducibility of VF was studied by programmed ventricular stimulation three times in each animal under the following: during normothermia (NT), after reaching the core temperature of 32°C (HT) and after another 60 minutes of stable hypothermia (HT60). Inducibility of VF, effective refractory period of the ventricles (ERP), QTc interval and potassium plasma levels were measured. RESULTS: Starting at normothermia of 38.7 (IQR 38.2; 39.8)°C, HT was achieved within 54 (39; 59) minutes and the core temperature was further maintained constant. Overall, the inducibility of VF was 100% (18/18 attempts) at NT, 83% (15/18) after reaching HT (P = 0.23) and 39% (7/18) at HT60 (P = 0.0001) using the same protocol. Similarly, ERP prolonged from 140 (130; 150) ms at NT to 206 (190; 220) ms when reaching HT (P < 0.001) and remained 206 (193; 220) ms at HT60. QTc interval was inversely proportional to the core temperature and extended from 376 (362; 395) at NT to 570 (545; 599) ms at HT. Potassium plasma level changed spontaneously: decreased during cooling from 4.1 (3.9; 4.8) to 3.7 (3.4; 4.1) mmol/L at HT (P < 0.01), then began to increase and returned to baseline level at HT60 (4.6 (4.4; 5.0) mmol/L, P = NS). CONCLUSIONS: According to our swine model, MTH does not increase the risk of VF induction by ventricular pacing in healthy hearts. Moreover, when combined with normokalemia, MTH exerts an antiarrhythmic effect despite prolonged QTc interval.

Reperfusion therapy for ST elevation acute myocardial infarction 2010/2011: current status in 37 ESC countries.

AIMS: Primary percutaneous coronary intervention (PPCI) is the preferred reperfusion therapy in ST-elevation myocardial infarction (STEMI). We conducted this study to evaluate the contemporary status on the use and type of reperfusion therapy in patients admitted with STEMI in the European Society of Cardiology (ESC) member countries. METHODS AND RESULTS: A cross-sectional descriptive study based on aggregated country-level data on the use of reperfusion therapy in patients admitted with STEMI during 2010 or 2011. Thirty-seven ESC countries were able to provide data from existing national or regional registries. In countries where no such registries exist, data were based on best expert estimates. Data were collected on the use of STEMI reperfusion treatment and mortality, the numbers of cardiologists, and the availability of PPCI facilities in each country. Our survey provides a brief data summary of the degree of variation in reperfusion therapy across Europe. The number of PPCI procedures varied between countries, ranging from 23 to 884 per million inhabitants. Primary percutaneous coronary intervention and thrombolysis were the dominant reperfusion strategy in 33 and 4 countries, respectively. The mean population served by a single PPCI centre with a 24-h service 7 days a week ranged from 31 300 inhabitants per centre to 6 533 000 inhabitants per centre. Twenty-seven of the total 37 countries participated in a former survey from 2007, and major increases in PPCI utilization were observed in 13 of these countries. CONCLUSION: Large variations in reperfusion treatment are still present across Europe. Countries in Eastern and Southern Europe reported that a substantial number of STEMI patients are not receiving any reperfusion therapy. Implementation of the best reperfusion therapy as recommended in the guidelines should be encouraged.

Left ventricle remodeling in men with moderate to severe volume-dependent hypertension.

We evaluated the influence of increased intravascular volume on the heart anatomy in salt-sensitive types of hypertension, represented by primary aldosteronism (PA) and low-renin essential hypertension (LREH). Echocardiography was performed in 128 males with moderate to severe or resistant hypertension: 44 patients had PA, 40 patients had LREH and 44 patients had normal-renin essential hypertension (NREH). Groups were comparable in demographic characteristics, blood pressure, duration of hypertension and previous antihypertensive treatment. Patients with PA and LREH, in comparison with NREH patients, showed both greater end-systolic (37.6±5.4 and 35.6±4.5 vs 32.6±4.4 mm, p<0.001 and p<0.05) and end-diastolic (56.1±4.5 and 54.0±4.8 vs 50.4±5.1 mm; p<0.001 and p<0.01) left ventricle (LV) diameter. There were no significant differences either in LV wall thicknesses or LV mass, although a higher percentage of patients with PA and LREH met the criteria of eccentric hypertrophy (p<0.001 and p<0.05 respectively). Aldosterone concentration was positively related to LV cavity dimensions, whether wall thicknesses were rather associated with blood pressure levels. In conclusion, plasma volume overload was identified as an important factor influencing LV remodeling in PA and LREH, whether due to excessive aldosterone levels in PA or other pathophysiological mechanisms.

Surprisingly delayed escalation of severe verapamil poisoning.

We present a case report of intoxication by a potentially lethal dose of sustained-release verapamil with delayed escalation of complications. The patient was hospitalized 1.5 h after an attempted suicide with a very high dose of verapamil sustained-release (7.2 g). On admission the plasma concentrations were extremely high (3600 ng/l). Heart rate and blood pressure declined slowly with a surprising sudden escalation on the third day coupled with hemodynamic collapse and loss of consciousness. Complete recovery was achieved in spite of 2 h of extreme hypotension. We outline the clinical course, a need for massive bowel irrigation in case of sustained-release medication, the timing of a temporary pacing and the effect of centralization of circulation even on invasively measured blood pressure.