The present study was conducted to recognize by part, the cardiovascular events of the nasopharyngeal reflex, through electrocardiographic interpretations. ECG patterns were traced in twelve clinically normal and healthy New Zealand White rabbits of both sexes, weighing between 2-3 kg and aged between 1-3 years with inhalant irritants. Immediately after induction of formaldehyde vapour, the heart rate fell by 69% from a mean of 192 &plusmn; 7.310 bpm to 60 &plusmn; 1.296 bpm, whereas exposure with cigarette smoke caused a fall in heart rate by 74% from a mean of 205 &plusmn; 9.605 bpm to 53 &plusmn; 3.065 bpm. With both irritants, P wave becomes smaller and totally disappeared, indicating an increased vagal activity inducing a sinoatrial node arrest. The amplitude of QRS complex also significantly decreased; and so did the duration of P wave and PR interval, presumably due to junctional escape. T wave duration decreased with slow ventricular repolarization. Bradycardia was also evident with increased QT interval. However, there was no change in QRS complex or ventricular depolarization, mediated perhaps via compensatory sympathetic influence on the ventricular myocardium. The study demonstrates that both formaldehyde and cigarette smoke provoked a similar protective response of rabbits against noxious fumes. 
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Electrocardiographic interpretation of the nasopharyngeal&nbsp;response in conscious rabbits

Background: Canine dilated cardiomyopathy (DCM) is one of the commonly diagnosed acquired myocardial disease in dogs characterized by hypokinesis, eccentric myocardial hypertrophy. Activation of neurohumoral system (i.e., sympathetic and RAAS) is crucial in the pathogenesis of DCM with deteriorative effect on the failing heart. In current protocol, ACE inhibitors are being employed to counter RAAS through blocking of ACE pathway, however aldosterone breakthrough due to alternate tissue pathway render the treatment less effective. The natriuretic peptides (viz., ANP, BNP) produced in response to cardiac wall stress have beneficial natriuretic, diuretic and suppressed cardiac sympathetic effects, however, will be cleaved by the enzyme neprilysin limiting their activity. With this background, this study was aimed to study the effect of Sacubitril-Valsartan, an ARNi drug in management of canine heart failure due to DCM, evaluating its effects on clinical, echocardiographic parameters as well as on RAAS and natriuretic peptides. 
 
Methods: Dogs with confirmed DCM on echocardiography were randomly divided into two treatment groups, one with conventional protocol having ACEI (Group II) and another group with ARNi replacing ACEI in the protocol (Group III). Clinical signs, ECG, echocardiographic evaluation was done at monthly interval till 90th&nbsp;day of therapy. Radiographic evaluation as well as effect on RAAS by assessing plasma natriuretic peptides and urine aldosterone-creatinine ratio was done on 0th&nbsp;day and 90th&nbsp;days of therapy. Data was analysed using ANOVA and independent &lsquo;t&rsquo; test followed by LSD using IBM SPSS version 2.0. 
 
Result: In the study, group III dogs showed early resolution of clinical signs compared to group II. Group III showed a significant decrease in left atrial diameter and LA/Ao ratio earlier by 30th&nbsp;day of therapy, while in Group II, the same was noticed on the 60th day. Cardiac internal diameters were found to be significantly decreased in group III while group II showed a non-significant decrease. Systolic function was found to be significantly increased by 30th&nbsp;day in group III while group III has a non significant increase in ejection fraction. Significant decline of Uald:cre ratio was noticed in group III indicating its effective inhibition of RAAS. In the study dogs treated with sacubitril-valsartan was found to have faster resolution of clinical signs, greater reduction in cardiac dimensions and improvement in systolic function compared to ACEI treated dogs. 
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Electrocardiographic interpretation of the nasopharyngeal response in conscious rabbits

Therapeutic Evaluation of Sacubitril-valsartan (Arni) in Canine Dilated Cardiomyopathy