For tachycardia

Combined Hj /H2 receptor stimulation by histamine is responsible for vasodilation-related symptoms, such as hypotension, flushing, and headache, as well as for tachycardia stimulated indirecdy through vasodilation and catecholamine secretion. 

TO, a 77-year-old male nursing home resident is admitted to the hospital with a 3-day history of altered mental status. The patient was unable to give a history or review of systems. On physical examination the vital signs revealed a blood pressure of 100/60 mm Hg, pulse 110 beats per minute, respirations 14/minutes, and a temperature of 101°F (38.3°C). Rales and dullness to percussion were noted at the posterior right base. The cardiac exam was significant for tachycardia. No edema was present. Laboratory studies included sodium 160 mEq/L (160 mmol/L), potassium 4.6 mEq/L (4.6 mmol/L), chloride 120 mEq/L (120 mmol/L), bicarbonate 30 mEq/L (30 mmol/L), glucose 104 mg/dL (5.77 mmol/L), BUN 34 mg/dL (12.14 mmol/L), and creatinine 2.2 mg/dL (194.5 pmol/L). The CBC was within normal limits. Chest x-ray indicated a right lower lobe pneumonia. 

Assess the patient with suspected heart disease for tachycardia, palpitations, and signs and symptoms of CHF, such as dyspnea... 

Blood pressure for hypotension and pulse rate for tachycardia, especially if the drug dosage has been increased rapidly... 

Blood pressure for hypotension and pulse rate for tachycardia... 

During the acute phase of a viral infection of the thyroid gland, there is destruction of thyroid parenchyma with transient release of stored thyroid hormones. A similar state may occur in patients with Hashimoto s thyroiditis. These episodes of transient thyrotoxicosis have been termed "spontaneously resolving hyperthyroidism." Supportive therapy is usually all that is necessary, such as propranolol for tachycardia and aspirin or nonsteroidal anti-inflammatory drugs to control local pain and fever. Corticosteroids may be necessary in severe cases to control the inflammation. 

Correct answer = D. Propranolol is a nonspecific p blocker that interferes with Pi receptors on the heart, causing bradycardia, that is, a slowing of the heart rate, Phenoxybenzamine blocks a receptors and prevents vasoconstriction of peripheral blood vessels by endogenous catecholamines. This leads to a decrease in blood pressure and peripheral resistance, which causes a reflex tachycardia. Isoproterenol is a potent p agonist that promotes tachycardia. Phentolamine is an a blocker that causes hypotension, which may set off refiex tachycardia. Prazosin is not indicated for tachycardia. 

SYMPATHOMIMETICS H2 RECEPTOR BLOCKERS t efficacy and adverse effects of sympathomimetics Unclear t hypertensive response dose reduction may be required. Monitor ECG for tachycardias... 

Tenamfetamine ( ecstasy, MDMA methylenedioxymethamphetamine) is structurally related to mescaline as well as to amphetamine. It was originally patented in 1914 as an appetite suppressant and has recently achieved widespread popularity as a dance drug at rave parties (where it is deemed necessary to keep pace with the beat and duration of the music popular names reflect the appearance of the tablets and capsules and include White Dove, White Burger, Red and Black, Denis the Menace). Tenamfetamine stimulates central and peripheral a-and p-adrenoceptors thus the pharmacological effects are compounded by those of physical exertion, dehydration and heat. In susceptible individuals (poor metabolisers who exhibit the CYP450 2D6 polymorphism) a severe and fatal idiosyncratic reaction may occur with fulminant hyperthermia, convulsioirs, disseminated intravascular coagulation, rhabdomyolysis, and acute renal and hepatic failure. Treatment includes activated charcoal, diazepam for convulsions, P-blockade (atenolol) for tachycardia, a-blockade (phentolamine) for hypertension, and dantrolene if the rectal temperature exceeds 39°C. 

As indicated in Figure 11-2, the compensatory responses can be counteracted with p-blockers or reserpine (for tachycardia) and diuretics or angiotensin antagonists (for salt and water retention). 

Thus as time passes a sensed heartbeat may fall into (i) a VF zone and be counted as a "VF" event, (ii) a VT zone, if present, and be counted as a "VT" event, or (iii) a ventricular sensing zone and be counted as a "VS" event. Once a beat is classified this process is repeated for each subsequent sensed ventricular heartbeat. Classification in a St Jude ICD also takes into account an average of the time interval of the three prior heartbeats in order to assign a ventricular heartbeat into a VF, VT, or VS zone. If enough beats are classified over time in a VF and/or VT zone, then the initial criterion for tachycardia detection may be satisfied. What constitutes "enough beats" is determined by the manner that the ICD counts and how the ICD has been programmed. 

A 43-year-old female with a biventricular ICD and history of atrial tachycardia complains of receiving multiple shocks from the device without warning. You obtain the following representative EGM sequence leading up to a shock from the device. The ICD utilizes sensing from both ventricular leads for tachycardia detection. 

A biventricular ICD that utilizes sensing from both ventricular leads for tachycardia detection can VT. 

Depends on rate, underlying cause, and patient s tolerance for tachycardia. 

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